upgrade ast 8.7.1

1 files changed, 1682 insertions, 0 deletions

diff --git a/ast/unitnormmap.c b/ast/unitnormmap.c
new file mode 100644
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--- /dev/null
+++ b/ast/unitnormmap.c
@@ -0,0 +1,1682 @@
+/*
+*class++
+*  Name:
+*     UnitNormMap
+
+*  Purpose:
+*     Convert a vector to a unit vector and its norm, relative to a specified centre.
+
+*  Constructor Function:
+c     astUnitNormMap
+f     AST_UNITNORMMAP
+
+*  Description:
+*     The forward transformation of a UnitNormMap subtracts the specified centre
+*     and then transforms the resulting vector to a unit vector and the vector norm.
+*     The output contains one more coordinate than the input: the initial
+*     Nin outputs are in the same order as the input; the final output is the norm.
+*     If the norm is 0, then the output of the forward transformation is AST__BAD
+*     for each component of the unit vector and 0 for the norm (the final value).
+*
+*     The inverse transformation of a UnitNormMap multiplies each component
+*     of the provided vector by the provided norm and adds the specified centre.
+*     The output contains one fewer coordinate than the input: the initial Nin inputs
+*     are in the same order as the output; the final input is the norm.
+*     If the provided norm is 0 then the other input values are ignored,
+*     and the output vector is the centre.
+*
+*     Example: if centre = [1, -1] then [5, 2] transforms to [4, 3] after subtracting the centre;
+*     the norm is 5, so the output is [0.8, 0.6, 5].
+*
+*     UnitNormMap enables radially symmetric transformations, as follows:
+*     - apply a UnitNormMap to produce a unit vector and norm (radius)
+*     - apply a one-dimensional mapping to the norm (radius), while passing the unit vector unchanged
+*     - apply the same UnitNormMap in the inverse direction to produce the result
+
+*  Inheritance:
+*     The UnitNormMap class inherits from the Mapping class.
+
+*  Attributes:
+*     The UnitNormMap class does not define any new attributes beyond those
+*     which are applicable to all Mappings.
+
+*  Functions:
+c     The UnitNormMap class does not define any new functions beyond those
+f     The UnitNormMap class does not define any new routines beyond those
+*     which are applicable to all Mappings.
+
+*  Copyright:
+*     Copyright (C) 2016 University of Washington
+
+*  Licence:
+*     This program is free software: you can redistribute it and/or
+*     modify it under the terms of the GNU Lesser General Public
+*     License as published by the Free Software Foundation, either
+*     version 3 of the License, or (at your option) any later
+*     version.
+*
+*     This program is distributed in the hope that it will be useful,
+*     but WITHOUT ANY WARRANTY; without even the implied warranty of
+*     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*     GNU Lesser General Public License for more details.
+*
+*     You should have received a copy of the GNU Lesser General
+*     License along with this program.  If not, see
+*     <http://www.gnu.org/licenses/>.
+
+*  Authors:
+*     RO: Russell Owen (LSST)
+*     DSB: David S Berry (EAO)
+
+*  History:
+*     20-APR-2016 (RO):
+*        Original version.
+*     17-MAR-2017 (DSB):
+*        Fix some memory leaks in MakeMergedMap.
+*     23-JAN-2017 (DSB):
+*        The length of the centre array is "Nin" for an uninverted
+*        UnitNormMap but "Nout" for an inverted UnitNormMap. Previously,
+*        it was always assumed to be Nin, which lead to a memory leak in
+*        the Copy function, etc.
+*class--
+*/
+
+/* Module Macros. */
+/* ============== */
+/* Set the name of the class we are implementing. This indicates to
+   the header files that define class interfaces that they should make
+   "protected" symbols available. */
+#define astCLASS UnitNormMap
+
+/* Macros which return the maximum and minimum of two values. */
+#define MAX(aa,bb) ((aa)>(bb)?(aa):(bb))
+#define MIN(aa,bb) ((aa)<(bb)?(aa):(bb))
+
+/* Macro to check for equality of floating point values. We cannot
+   compare bad values directory because of the danger of floating point
+   exceptions, so bad values are dealt with explicitly. */
+#define EQUAL(aa,bb) (((aa)==AST__BAD)?(((bb)==AST__BAD)?1:0):(((bb)==AST__BAD)?0:(fabs((aa)-(bb))<=1.0E9*MAX((fabs(aa)+fabs(bb))*DBL_EPSILON,DBL_MIN))))
+
+/* Include files. */
+/* ============== */
+/* Interface definitions. */
+/* ---------------------- */
+
+#include "globals.h"             /* Thread-safe global data access */
+#include "error.h"               /* Error reporting facilities */
+#include "memory.h"              /* Memory management facilities */
+#include "object.h"              /* Base Object class */
+#include "pointset.h"            /* Sets of points/coordinates */
+#include "unitmap.h"             /* Unit mappings */
+#include "mapping.h"             /* Coordinate mappings (parent class) */
+#include "shiftmap.h"            /* ShiftMap */
+#include "winmap.h"            /* ShiftMap */
+#include "channel.h"             /* I/O channels */
+#include "unitnormmap.h"         /* Interface definition for this class */
+
+/* Error code definitions. */
+/* ----------------------- */
+#include "ast_err.h"             /* AST error codes */
+
+/* C header files. */
+/* --------------- */
+#include <float.h>
+#include <math.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+/* Module Variables. */
+/* ================= */
+
+/* Address of this static variable is used as a unique identifier for
+   member of this class. */
+static int class_check;
+
+/* Pointers to parent class methods which are extended by this class. */
+static int (* parent_getobjsize)( AstObject *, int * );
+static AstPointSet *(* parent_transform)( AstMapping *, AstPointSet *, int, AstPointSet *, int * );
+
+
+#ifdef THREAD_SAFE
+/* Define how to initialise thread-specific globals. */
+#define GLOBAL_inits \
+   globals->Class_Init = 0;
+
+/* Create the function that initialises global data for this module. */
+astMAKE_INITGLOBALS(UnitNormMap)
+
+/* Define macros for accessing each item of thread specific global data. */
+#define class_init astGLOBAL(UnitNormMap,Class_Init)
+#define class_vtab astGLOBAL(UnitNormMap,Class_Vtab)
+
+
+#include <pthread.h>
+
+
+#else
+
+
+/* Define the class virtual function table and its initialisation flag
+   as static variables. */
+static AstUnitNormMapVtab class_vtab;   /* Virtual function table */
+static int class_init = 0;       /* Virtual function table initialised? */
+
+#endif
+
+/* External Interface Function Prototypes. */
+/* ======================================= */
+/* The following functions have public prototypes only (i.e. no
+   protected prototypes), so we must provide local prototypes for use
+   within this module. */
+AstUnitNormMap *astUnitNormMapId_( int, const double [], const char *, ... );
+
+/* Prototypes for Private Member Functions. */
+/* ======================================== */
+
+static AstPointSet *Transform( AstMapping *, AstPointSet *, int, AstPointSet *, int * );
+static int GetMappingType( AstMapping *, int * );
+static AstMapping * MakeMergedMap( AstMapping *, AstMapping *, int * );
+static int GetObjSize( AstObject *, int * );
+static int MapMerge( AstMapping *, int, int, int *, AstMapping ***, int **, int * );
+static void Copy( const AstObject *, AstObject *, int * );
+static void Delete( AstObject *, int * );
+static void Dump( AstObject *, AstChannel *, int * );
+static int GetIsLinear( AstMapping *, int * );
+
+/* Member functions. */
+/* ================= */
+static int GetMappingType( AstMapping *map, int *status ) {
+/*
+*
+*  Name:
+*     GetMappingType
+
+*  Purpose:
+*     Return a code describing the mapping type, to aid simplification.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     int MakeMergedMap( AstMapping *map1, AstMapping *map2, int inv1, int inv2, int *status )
+
+*  Class Membership:
+*     UnitNormMap internal utility function.
+
+*  Description:
+*     This function returns an integer code describing the type of a mapping,
+*     to help with merging two mappings. The codes are:
+*     3 = WinMap
+*     2 = ShiftMap
+*     1 = UnitNormMap
+*     0 = other
+
+*  Parameters:
+*     map
+*        A pointer to the mapping
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     A pointer to the merged mapping, or NULL if the Mappings cannot be merged
+
+*/
+   const char *class = astGetClass( map );
+   int type = 0;
+   if( strcmp( class, "UnitNormMap" ) == 0 ) {
+      type = 1;
+   } else if( strcmp( class, "ShiftMap" ) == 0 ) {
+      type = 2;
+   } else if( strcmp( class, "WinMap" ) == 0){
+      type = 3;
+   }
+   return type;
+}
+
+static AstMapping * MakeMergedMap( AstMapping *map1, AstMapping *map2, int *status ){
+/*
+*
+*  Name:
+*     MakeMergedMap
+
+*  Purpose:
+*     Make a single Mapping that is equivalent to the merging of two other Mappings,
+*     one of which must be a UnitNormMap.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     int MakeMergedMap( AstMapping *map1, AstMapping *map2, int inv1, int inv2, int *status )
+
+*  Class Membership:
+*     UnitNormMap internal utility function.
+
+*  Description:
+*     This function returns a single Mapping that is the equivalent of the two supplied Mappings,
+*     if they can be merged. One of the pair must be a UnitNormMap.
+*
+*     Supported merges, which must be in series:
+*     ShiftMap               + UnitNormMap(forward)            = UnitNormMap(forward)
+*     WinMap with unit scale + UnitNormMap(forward)            = UnitNormMap(forward)
+*     UnitNormMap(inverted)  + ShiftMap                        = UnitNormMap(inverted)
+*     UnitNormMap(inverted)  + WinMap with unit scale          = UnitNormMap(inverted)
+*     UnitNormMap(forward)   + identical UnitNormMap(inverted) = UnitMap
+*     UnitNormMap(inverted)  + identical UnitNormMap(forward)  = UnitMap
+*     UnitNormMap(forward)   + UnitNormMap(inverted)           = ShiftMap
+*
+*
+*     Notes:
+*     - A UnitMap before or after a UnitNormMap = the UnitNormMap, but UnitMap takes care of that merge.
+*     - The code that checks for ShiftMap + UnitNormMap probably never runs, because ShiftMap is
+*       converted to WinMap during simplification before it gets here.
+
+*  Parameters:
+*     map1
+*        A pointer to the first mapping.
+*     map2
+*        A pointer to the second mapping.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     A pointer to the merged mapping, or NULL if the Mappings cannot be merged
+
+*/
+
+/* Check the global error status. */
+   if( !astOK ) return NULL;
+
+/* Initialise returned mapping */
+   AstMapping *retmap = NULL;
+
+/* Set type to 1=UnitNormMap, 2=ShiftMap, 0=other for both maps */
+   int type1 = GetMappingType( map1, status );
+   int type2 = GetMappingType( map2, status );
+   if( !astOK ) return NULL;
+
+   if( type1 == 0 || type2 == 0 ) return NULL;  /* can only merge with UnitNormMap or ShiftMap */
+
+   if( !(type1 == 1 || type2 == 1) ) return NULL;  /* one must be a UnitNormMap */
+
+   if( type1 == 2 ) {
+      if( astGetInvert( map2 )) return NULL;  /* ShiftMap + UnitNormMap(inverted) not supported */
+
+/* ShiftMap + UnitNormMap(forward) = UnitNormMap(forward) */
+      AstShiftMap *shiftmap = (AstShiftMap *) map1;
+      AstUnitNormMap *unm = (AstUnitNormMap *) map2;
+      int nin = astGetNin( shiftmap );
+      double shiftmult = astGetInvert( shiftmap ) ? -1 : 1;
+      double *newcentre = astMalloc( sizeof(double)*(size_t)nin );
+      if( astOK ) {
+         int coord = 0;
+         for( coord = 0; coord < nin; coord++ ){
+            newcentre[coord] = unm->centre[coord] - shiftmult*shiftmap->shift[coord];
+         }
+         retmap = (AstMapping *) astUnitNormMap( nin, newcentre, "", status );
+         newcentre = astFree( (void *) newcentre );
+      }
+   } else if( type1 == 3 ) {
+      if( astGetInvert( map2 )) return NULL;  /* WinMap + UnitNormMap(inverted) not supported */
+
+/* WinMap with unit scale + UnitNormMap(forward) = UnitNormMap(forward);
+   Do not create a returned Mapping (but do free the newcentre memory) if WinMap
+   does not have unit scale */
+      AstWinMap *winmap = (AstWinMap *) map1;
+      AstUnitNormMap *unm = (AstUnitNormMap *) map2;
+      int nin = astGetNin( winmap );
+      double shiftmult = astGetInvert( winmap ) ? -1 : 1;
+      double *newcentre = astMalloc( sizeof(double)*(size_t)nin );
+      if( astOK ) {
+         int coord = 0;
+         int ok = 1;
+         for( coord = 0; coord < nin; coord++ ){
+            if( !EQUAL( winmap->b[coord], 1.0 )) ok = 0;
+            newcentre[coord] = unm->centre[coord] - shiftmult*winmap->a[coord];
+         }
+         if( ok ) retmap = (AstMapping *) astUnitNormMap( nin, newcentre, "", status );
+         newcentre = astFree( (void *) newcentre );
+      }
+   } else if( type2 == 2 ) {
+      if( !astGetInvert( map1 )) return NULL;  /* UnitNormMap(forward) + ShiftMap not supported */
+
+/* UnitNormMap(inverted) + ShiftMap = UnitNormMap(inverted) */
+      AstShiftMap *shiftmap = (AstShiftMap *) map2;
+      AstUnitNormMap *unm = (AstUnitNormMap *) map1;
+      int nin = astGetNin( shiftmap );
+      double shiftmult = astGetInvert( shiftmap ) ? -1 : 1;
+      double *newcentre = astMalloc( sizeof(double)*(size_t)nin );
+      if( astOK ) {
+         int coord = 0;
+         for( coord = 0; coord < nin; coord++ ){
+            newcentre[coord] = unm->centre[coord] + shiftmult*shiftmap->shift[coord];
+         }
+         retmap = (AstMapping *) astUnitNormMap( nin, newcentre, "Invert=1", status );
+         newcentre = astFree( (void *) newcentre );
+      }
+   } else if( type2 == 3 ) {
+      if( !astGetInvert( map1 )) return NULL;  /* UnitNormMap(forward) + WinMap not supported */
+
+/* UnitNormMap(inverted) + WinMap = UnitNormMap(inverted);
+   Do not create a returned Mapping - but do free the newcentre memory - if WinMap
+   does not have unit scale */
+      AstWinMap *winmap = (AstWinMap *) map2;
+      AstUnitNormMap *unm = (AstUnitNormMap *) map1;
+      int nin = astGetNin( winmap );
+      double shiftmult = astGetInvert( winmap ) ? -1 : 1;
+      double *newcentre = astMalloc( sizeof(double)*(size_t)nin );
+      if( astOK ) {
+         int coord = 0;
+         int ok = 1;
+         for( coord = 0; coord < nin; coord++ ){
+            if( !EQUAL( winmap->b[coord], 1.0 )) ok = 0;
+            newcentre[coord] = unm->centre[coord] + shiftmult*winmap->a[coord];
+         }
+         if( ok ) retmap = (AstMapping *) astUnitNormMap( nin, newcentre, "Invert=1", status );
+         newcentre = astFree( (void *) newcentre );
+      }
+   } else {
+      if( !astGetInvert( map1 ) == !astGetInvert( map2 )) return NULL;  /* UNMs must have opposite dir. */
+
+/* Two UnitNormMaps in opposite directions */
+      AstUnitNormMap *unm1 = (AstUnitNormMap *) map1;
+      AstUnitNormMap *unm2 = (AstUnitNormMap *) map2;
+
+      int ctrlen = MIN( astGetNin( map1 ), astGetNin( map2 ) );
+      int centres_equal = 1;
+      int i = 0;
+      for( i = 0; i < ctrlen; i++ ){
+         if( !EQUAL( unm1->centre[i], unm2->centre[i] )){
+            centres_equal = 0;
+            break;
+         }
+      }
+      if( centres_equal ) {
+
+/* Two UnitNormMap in opposite directions with identical centres = UnitMap */
+         retmap = (AstMapping *) astUnitMap( astGetNin( map1 ), "", status );
+      } else {
+         if( astGetInvert( map2 )) {
+
+/* UnitNormMap(forward) + UnitNormMap(inverted) = ShiftMap */
+            int nin = astGetNin( map1 );
+            double *shift = astMalloc( sizeof(double)*(size_t)nin );
+            if( astOK ) {
+               int coord = 0;
+               for( coord = 0; coord < nin; coord++ ){
+                  shift[coord] = unm2->centre[coord] - unm1->centre[coord];
+               }
+               retmap = (AstMapping *) astShiftMap( nin, shift, "", status );
+               shift = astFree( (void *) shift );
+            }
+         }
+      }
+   }
+
+   return astOK ? retmap : NULL;
+}
+
+static int GetIsLinear( AstMapping *this_mapping, int *status ){
+/*
+*  Name:
+*     GetIsLinear
+
+*  Purpose:
+*     Return the value of the IsLinear attribute for a UnitNormMap.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "mapping.h"
+*     void GetIsLinear( AstMapping *this, int *status )
+
+*  Class Membership:
+*     UnitNormMap member function (over-rides the protected astGetIsLinear
+*     method inherited from the Mapping class).
+
+*  Description:
+*     This function returns the value of the IsLinear attribute for a
+*     Frame, which is always one.
+
+*  Parameters:
+*     this
+*        Pointer to the UnitNormMap.
+*     status
+*        Pointer to the inherited status variable.
+*/
+   return 0;
+}
+
+static int GetObjSize( AstObject *this_object, int *status ) {
+/*
+*  Name:
+*     GetObjSize
+
+*  Purpose:
+*     Return the in-memory size of an Object.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     int GetObjSize( AstObject *this, int *status )
+
+*  Class Membership:
+*     UnitNormMap member function (over-rides the astGetObjSize protected
+*     method inherited from the parent class).
+
+*  Description:
+*     This function returns the in-memory size of the supplied UnitNormMap,
+*     in bytes.
+
+*  Parameters:
+*     this
+*        Pointer to the UnitNormMap.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     The Object size, in bytes.
+
+*  Notes:
+*     - A value of zero will be returned if this function is invoked
+*     with the global status set, or if it should fail for any reason.
+*/
+
+/* Initialise. */
+   int result = 0;
+
+/* Check the global error status. */
+   if( !astOK ) return result;
+
+/* Obtain a pointers to the UnitNormMap structure. */
+   AstUnitNormMap *this = (AstUnitNormMap *) this_object;
+
+/* Invoke the GetObjSize method inherited from the parent class, and then
+   add on any components of the class structure defined by thsi class
+   which are stored in dynamically allocated memory. */
+   result = (*parent_getobjsize)( this_object, status );
+   result += astTSizeOf( this->centre );
+
+/* If an error occurred, clear the result value. */
+   if( !astOK ) result = 0;
+
+/* Return the result, */
+   return result;
+}
+
+void astInitUnitNormMapVtab_(  AstUnitNormMapVtab *vtab, const char *name, int *status ) {
+/*
+*+
+*  Name:
+*     astInitUnitNormMapVtab
+
+*  Purpose:
+*     Initialise a virtual function table for a UnitNormMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     void astInitUnitNormMapVtab( AstUnitNormMapVtab *vtab, const char *name )
+
+*  Class Membership:
+*     UnitNormMap vtab initialiser.
+
+*  Description:
+*     This function initialises the component of a virtual function
+*     table which is used by the UnitNormMap class.
+
+*  Parameters:
+*     vtab
+*        Pointer to the virtual function table. The components used by
+*        all ancestral classes will be initialised if they have not already
+*        been initialised.
+*     name
+*        Pointer to a constant null-terminated character string which contains
+*        the name of the class to which the virtual function table belongs (it
+*        is this pointer value that will subsequently be returned by the Object
+*        astClass function).
+*-
+*/
+
+/* Check the local error status. */
+   if( !astOK ) return;
+
+/* Get a pointer to the thread specific global data structure. */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   astGET_GLOBALS(NULL);
+
+/* Initialize the component of the virtual function table used by the
+   parent class. */
+   astInitMappingVtab( (AstMappingVtab *) vtab, name );
+
+/* Store a unique "magic" value in the virtual function table. This
+   will be used (by astIsAUnitNormMap) to determine if an object belongs
+   to this class.  We can conveniently use the address of the (static)
+   class_check variable to generate this unique value. */
+   vtab->id.check = &class_check;
+   vtab->id.parent = &(((AstMappingVtab *) vtab)->id);
+
+/* Initialise member function pointers. */
+/* ------------------------------------ */
+/* Store pointers to the member functions (implemented here) that provide
+   virtual methods for this class. */
+
+/* Save the inherited pointers to methods that will be extended, and
+   replace them with pointers to the new member functions. */
+   AstObjectVtab *object = (AstObjectVtab *) vtab;
+   AstMappingVtab *mapping = (AstMappingVtab *) vtab;
+   parent_getobjsize = object->GetObjSize;
+   object->GetObjSize = GetObjSize;
+
+   parent_transform = mapping->Transform;
+   mapping->Transform = Transform;
+
+/* Store replacement pointers for methods which will be over-ridden by
+   new member functions implemented here. */
+   mapping->MapMerge = MapMerge;
+   mapping->GetIsLinear = GetIsLinear;
+
+/* Declare the class dump, copy and delete functions.*/
+   astSetDump( vtab, Dump, "UnitNormMap", "Compute unit vector and norm relative to a centre" );
+   astSetCopy( (AstObjectVtab *) vtab, Copy );
+   astSetDelete( (AstObjectVtab *) vtab, Delete );
+
+/* If we have just initialised the vtab for the current class, indicate
+   that the vtab is now initialised, and store a pointer to the class
+   identifier in the base "object" level of the vtab. */
+   if( vtab == &class_vtab ) {
+      class_init = 1;
+      astSetVtabClassIdentifier( vtab, &(vtab->id) );
+   }
+}
+
+static int MapMerge( AstMapping *this, int where, int series, int *nmap,
+                     AstMapping ***map_list, int **invert_list, int *status ) {
+/*
+*  Name:
+*     MapMerge
+
+*  Purpose:
+*     Simplify a sequence of Mappings containing a UnitNormMap.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "mapping.h"
+*     int MapMerge( AstMapping *this, int where, int series, int *nmap,
+*                   AstMapping ***map_list, int **invert_list, int *status )
+
+*  Class Membership:
+*     UnitNormMap method (over-rides the protected astMapMerge method
+*     inherited from the Mapping class).
+
+*  Description:
+*     This function attempts to simplify a sequence of Mappings by
+*     merging a nominated UnitNormMap in the sequence with its neighbours,
+*     so as to shorten the sequence if possible.
+*
+*     In many cases, simplification will not be possible and the
+*     function will return -1 to indicate this, without further
+*     action.
+*
+*     In most cases of interest, however, this function will either
+*     attempt to replace the nominated UnitNormMap with a Mapping which it
+*     considers simpler, or to merge it with the Mappings which
+*     immediately precede it or follow it in the sequence (both will
+*     normally be considered). This is sufficient to ensure the
+*     eventual simplification of most Mapping sequences by repeated
+*     application of this function.
+*
+*     In some cases, the function may attempt more elaborate
+*     simplification, involving any number of other Mappings in the
+*     sequence. It is not restricted in the type or scope of
+*     simplification it may perform, but will normally only attempt
+*     elaborate simplification in cases where a more straightforward
+*     approach is not adequate.
+
+*  Parameters:
+*     this
+*        Pointer to the nominated UnitNormMap which is to be merged with
+*        its neighbours. This should be a cloned copy of the UnitNormMap
+*        pointer contained in the array element "(*map_list)[where]"
+*        (see below). This pointer will not be annulled, and the
+*        UnitNormMap it identifies will not be modified by this function.
+*     where
+*        Index in the "*map_list" array (below) at which the pointer
+*        to the nominated UnitNormMap resides.
+*     series
+*        A non-zero value indicates that the sequence of Mappings to
+*        be simplified will be applied in series (i.e. one after the
+*        other), whereas a zero value indicates that they will be
+*        applied in parallel (i.e. on successive sub-sets of the
+*        input/output coordinates).
+*     nmap
+*        Address of an int which counts the number of Mappings in the
+*        sequence. On entry this should be set to the initial number
+*        of Mappings. On exit it will be updated to record the number
+*        of Mappings remaining after simplification.
+*     map_list
+*        Address of a pointer to a dynamically allocated array of
+*        Mapping pointers (produced, for example, by the astMapList
+*        method) which identifies the sequence of Mappings. On entry,
+*        the initial sequence of Mappings to be simplified should be
+*        supplied.
+*
+*        On exit, the contents of this array will be modified to
+*        reflect any simplification carried out. Any form of
+*        simplification may be performed. This may involve any of: (a)
+*        removing Mappings by annulling any of the pointers supplied,
+*        (b) replacing them with pointers to new Mappings, (c)
+*        inserting additional Mappings and (d) changing their order.
+*
+*        The intention is to reduce the number of Mappings in the
+*        sequence, if possible, and any reduction will be reflected in
+*        the value of "*nmap" returned. However, simplifications which
+*        do not reduce the length of the sequence (but improve its
+*        execution time, for example) may also be performed, and the
+*        sequence might conceivably increase in length (but normally
+*        only in order to split up a Mapping into pieces that can be
+*        more easily merged with their neighbours on subsequent
+*        invocations of this function).
+*
+*        If Mappings are removed from the sequence, any gaps that
+*        remain will be closed up, by moving subsequent Mapping
+*        pointers along in the array, so that vacated elements occur
+*        at the end. If the sequence increases in length, the array
+*        will be extended (and its pointer updated) if necessary to
+*        accommodate any new elements.
+*
+*        Note that any (or all) of the Mapping pointers supplied in
+*        this array may be annulled by this function, but the Mappings
+*        to which they refer are not modified in any way (although
+*        they may, of course, be deleted if the annulled pointer is
+*        the final one).
+*     invert_list
+*        Address of a pointer to a dynamically allocated array which,
+*        on entry, should contain values to be assigned to the Invert
+*        attributes of the Mappings identified in the "*map_list"
+*        array before they are applied (this array might have been
+*        produced, for example, by the astMapList method). These
+*        values will be used by this function instead of the actual
+*        Invert attributes of the Mappings supplied, which are
+*        ignored.
+*
+*        On exit, the contents of this array will be updated to
+*        correspond with the possibly modified contents of the
+*        "*map_list" array.  If the Mapping sequence increases in
+*        length, the "*invert_list" array will be extended (and its
+*        pointer updated) if necessary to accommodate any new
+*        elements.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     If simplification was possible, the function returns the index
+*     in the "map_list" array of the first element which was
+*     modified. Otherwise, it returns -1 (and makes no changes to the
+*     arrays supplied).
+
+*  Notes:
+*     - A value of -1 will be returned if this function is invoked
+*     with the global error status set, or if it should fail for any
+*     reason.
+*/
+
+/* Initialise. */
+   int result = -1;
+
+/* Check the global error status. */
+   if( !astOK ) return result;
+
+   if( series ) {
+
+/* In series */
+/* Try to merge UnitNormMap with either of its neighbours. */
+      AstMapping *map1 = NULL;    /* The first Mapping to merge */
+      AstMapping *map2 = NULL;    /* The second Mapping to merge */
+      AstMapping *newmap = NULL;  /* The merged Mapping */
+      int i1 = MAX( where - 1, 0 );
+      int i2 = i1 + 1;
+      for( ; i2 < *nmap; i1++, i2++ ){
+         map1 = ( *map_list )[ i1 ];
+         map2 = ( *map_list )[ i2 ];
+         int wasinverted1 = astGetInvert( map1 );
+         int wasinverted2 = astGetInvert( map2 );
+         astSetInvert( map1, ( *invert_list )[ i1 ] );
+         astSetInvert( map2, ( *invert_list )[ i2 ] );
+         newmap = MakeMergedMap( map1, map2, status );
+         astSetInvert( map1, wasinverted1 );
+         astSetInvert( map2, wasinverted2 );
+         if( newmap ) break;
+      }
+
+      if( !newmap ) return -1;
+      if( !astOK ) {
+         astAnnul( newmap );
+         return -1;
+      }
+
+/* Annul the first of the two Mappings, and replace it with the merged Mapping.
+   Also update the invert flag. */
+      (void) astAnnul( map1 );
+      ( *map_list )[ i1 ] = newmap;
+      ( *invert_list )[ i1 ] = astGetInvert( newmap );
+
+/* Annul the second of the two Mappings, and shuffle down the rest of the list to fill the gap. */
+      (void) astAnnul( map2 );
+      int i = 0;
+      for( i = i2 + 1; i < *nmap; i++ ) {
+         ( *map_list )[ i - 1 ] = ( *map_list )[ i ];
+         ( *invert_list )[ i - 1 ] = ( *invert_list )[ i ];
+      }
+
+/* Clear the vacated element at the end. */
+      ( *map_list )[ *nmap - 1 ] = NULL;
+      ( *invert_list )[ *nmap - 1 ] = 0;
+
+/* Decrement the Mapping count and return the index of the first modified element. */
+      ( *nmap )--;
+      result = i1;
+
+   } else {
+
+/* In parallel. */
+/* UnitNormMaps cannot combine in parallel with any other Mappings. */
+   }
+
+/* Return the result. */
+   return result;
+}
+
+static AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+                               int forward, AstPointSet *out, int *status ) {
+/*
+*  Name:
+*     Transform
+
+*  Purpose:
+*     Apply a UnitNormMap to transform a set of points.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     AstPointSet *Transform( AstMapping *this, AstPointSet *in,
+*                             int forward, AstPointSet *out, int *status )
+
+*  Class Membership:
+*     UnitNormMap member function (over-rides the astTransform protected
+*     method inherited from the Mapping class).
+
+*  Description:
+*     This function takes a UnitNormMap and a set of points encapsulated in a
+*     PointSet and transforms the points so as to map them into the
+*     required window.
+
+*  Parameters:
+*     this
+*        Pointer to the UnitNormMap.
+*     in
+*        Pointer to the PointSet holding the input coordinate data.
+*     forward
+*        A non-zero value indicates that the forward coordinate transformation
+*        should be applied, while a zero value requests the inverse
+*        transformation.
+*     out
+*        Pointer to a PointSet which will hold the transformed (output)
+*        coordinate values. A NULL value may also be given, in which case a
+*        new PointSet will be created by this function.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Returned Value:
+*     Pointer to the output (possibly new) PointSet.
+
+*  Notes:
+*     -  A null pointer will be returned if this function is invoked with the
+*     global error status set, or if it should fail for any reason.
+*     -  The number of coordinate values per point in the input PointSet must
+*     match the number of coordinates for the UnitNormMap being applied.
+*     -  If an output PointSet is supplied, it must have space for sufficient
+*     number of points and coordinate values per point to accommodate the
+*     result. Any excess space will be ignored.
+*/
+
+/* Check the global error status. */
+   if( !astOK ) return NULL;
+
+/* Obtain a pointer to the UnitNormMap. */
+   AstUnitNormMap *map = (AstUnitNormMap *) this;
+
+/* Apply the parent mapping using the stored pointer to the Transform member
+   function inherited from the parent Mapping class. This function validates
+   all arguments and generates an output PointSet if necessary, but does not
+   actually transform any coordinate values. */
+   AstPointSet *result = (*parent_transform)( this, in, forward, out, status );
+
+/* We will now extend the parent astTransform method by performing the
+   calculations needed to generate the output coordinate values. */
+
+/* Determine the numbers of points and coordinates per point from the input
+   PointSet and obtain pointers for accessing the input and output coordinate
+   values. */
+   int ncoord_in = astGetNcoord( in );
+   int ncoord_out = astGetNcoord( result );
+   int npoint = astGetNpoint(in);
+   double **ptr_in = astGetPoints(in);
+   double **ptr_out = astGetPoints( result );
+
+/* Determine whether to apply the forward or inverse mapping, according to the
+   direction specified and whether the mapping has been inverted. */
+   if( astGetInvert(map) ){
+      forward = !forward;
+   }
+
+/* Report an error if the UnitNormMap does not contain a centre. */
+   if( !map->centre && astOK ){
+      const char *class = astGetClass( this );
+      astError( AST__BADSM, "astTransform(%s): The supplied %s does not "
+                "contain any centre information.", status, class, class );
+   }
+
+/* Perform coordinate arithmetic. */
+/* ------------------------------ */
+   if( astOK ){
+
+/* If any centre coordinate is bad then set all outputs bad */
+      int const ncoord_centre = forward ? ncoord_in : ncoord_out;
+      int coord_ctr = 0;
+      for( coord_ctr = 0; coord_ctr < ncoord_centre; coord_ctr++ ){
+         if( (map->centre)[coord_ctr] == AST__BAD ){
+            int coord_out = 0;
+            for( coord_out = 0; coord_out < ncoord_out; coord_out++ ){
+               int point = 0;
+               for( point = 0; point < npoint; point++ ){
+                  ptr_out[point][coord_out] = AST__BAD;
+               }
+            }
+            return result;
+         }
+      }
+
+      if( forward ){
+
+/* Forward transformation: vector to unit vector, norm */
+         int point = 0;
+         for( point = 0; point < npoint; point++ ){
+
+/* Compute max_relin: the maximum absolute input value relative to centre */
+            double max_relin = 0;
+            int coord_in = 0;
+            for( coord_in = 0; coord_in < ncoord_in; coord_in++ ){
+               double in = ptr_in[coord_in][point];
+               if( in == AST__BAD ){
+
+/* An input coord is bad, so all outputs are bad */
+                  int coord_out = 0;
+                  for( coord_out = 0; coord_out < ncoord_out; coord_out++ ){
+                     ptr_out[coord_out][point] = AST__BAD;
+                  }
+                  goto forward_next_point;
+               }
+               double abs_relin = fabs(in - map->centre[coord_in]);
+               if( abs_relin > max_relin ){
+                  max_relin = abs_relin;
+               }
+            }
+
+            if( max_relin == 0 ){
+
+/* The norm is 0, so the unit vector (first nin components of output) is unknown */
+               int coord = 0;
+               for( coord = 0; coord < ncoord_out - 1; coord++ ){
+                  ptr_out[coord][point] = AST__BAD;
+               }
+               ptr_out[ncoord_out - 1][point] = 0;
+               continue;
+            }
+
+/* All is well; compute scaled_sum as the sum of (relin/max_relin)^2 for each input
+   where relin = in - centre (the scaling avoids overflow),
+   then compute norm = max_relin * sqrt(scaled_sum) and set all outputs */
+            double scaled_sum = 0;
+            int coord = 0;
+            for( coord = 0; coord < ncoord_in; coord++ ){
+               double scaled_in = (ptr_in[coord][point] - map->centre[coord])/max_relin;
+               scaled_sum += scaled_in*scaled_in;
+            }
+            double norm = max_relin*sqrt(scaled_sum);
+            for( coord = 0; coord < ncoord_in; coord++ ){
+               ptr_out[coord][point] = (ptr_in[coord][point] - map->centre[coord])/norm;
+            }
+            ptr_out[ncoord_out - 1][point] = norm;
+
+            forward_next_point: ;
+         }
+      } else {
+
+/* Inverse transformation: unit vector, norm -> vector */
+         int point = 0;
+         for( point = 0; point < npoint; point++ ){
+            double norm = ptr_in[ncoord_in-1][point];
+            if( norm == AST__BAD ){
+
+/* Norm is bad for this point; set all output coords bad */
+               int coord = 0;
+               for( coord = 0; coord < ncoord_out; coord++ ){
+                  ptr_out[coord][point] = AST__BAD;
+               }
+            } else if( norm == 0 ){
+
+/* Norm is 0 for this point; set the output to the centre */
+               int coord = 0;
+               for( coord = 0; coord < ncoord_out; coord++ ){
+                  ptr_out[coord][point] = map->centre[coord];
+               }
+            } else {
+               int coord = 0;
+               for( coord = 0; coord < ncoord_out; coord++ ){
+                  double in = ptr_in[coord][point];
+                  if( in == AST__BAD ){
+                     ptr_out[coord][point] = AST__BAD;
+                  } else {
+                     ptr_out[coord][point] = in*norm + map->centre[coord];
+                  }
+               }
+            }
+         }
+      }
+   }
+
+/* Return a pointer to the output PointSet. */
+   return result;
+}
+
+/* Functions which access class attributes. */
+/* ---------------------------------------- */
+/* Implement member functions to access the attributes associated with
+   this class using the macros defined for this purpose in the
+   "object.h" file. For a description of each attribute, see the class
+   interface (in the associated .h file). */
+
+/* Copy constructor. */
+/* ----------------- */
+static void Copy( const AstObject *objin, AstObject *objout, int *status ) {
+/*
+*  Name:
+*     Copy
+
+*  Purpose:
+*     Copy constructor for UnitNormMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Copy( const AstObject *objin, AstObject *objout, int *status )
+
+*  Description:
+*     This function implements the copy constructor for UnitNormMap objects.
+
+*  Parameters:
+*     objin
+*        Pointer to the UnitNormMap to be copied.
+*     objout
+*        Pointer to the UnitNormMap being constructed.
+*     status
+*        Pointer to the inherited status variable.
+
+*/
+
+/* Local Variables: */
+   AstUnitNormMap *out;              /* Pointer to output UnitNormMap */
+   AstUnitNormMap *in;               /* Pointer to input UnitNormMap */
+   int ncoord;                  /* No. of axes for the mapping */
+
+/* Check the global error status. */
+   if( !astOK ) return;
+
+/* Obtain a pointer to the input and output UnitNormMaps. */
+   in= (AstUnitNormMap *) objin;
+   out = (AstUnitNormMap *) objout;
+
+/* Get the length of the centre array. */
+   ncoord = astGetInvert( in ) ? astGetNout( in ) : astGetNin( in );
+
+/* Allocate memory holding copies of the centre defining the mapping. */
+   out->centre = (double *) astStore( NULL, (void *) in->centre,
+                                      sizeof(double)*(size_t)ncoord );
+
+/* If an error occurred, free any allocated memory. */
+   if( !astOK ) {
+      out->centre = (double *) astFree( (void *) out->centre );
+   }
+
+}
+
+/* Destructor. */
+/* ----------- */
+static void Delete( AstObject *obj, int *status ) {
+/*
+*  Name:
+*     Delete
+
+*  Purpose:
+*     Destructor for UnitNormMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Delete( AstObject *obj, int *status )
+
+*  Description:
+*     This function implements the destructor for UnitNormMap objects.
+
+*  Parameters:
+*     obj
+*        Pointer to the UnitNormMap to be deleted.
+*     status
+*        Pointer to the inherited status variable.
+
+*  Notes:
+*     - This destructor does nothing and exists only to maintain a
+*     one-to-one correspondence between destructors and copy
+*     constructors.
+*/
+
+/* Local Variables: */
+   AstUnitNormMap *this;              /* Pointer to UnitNormMap */
+
+/* Obtain a pointer to the UnitNormMap structure. */
+   this = (AstUnitNormMap *) obj;
+
+/* Free the memory holding the centre. */
+   this->centre = (double *) astFree( (void *) this->centre );
+
+}
+
+/* Dump function. */
+/* -------------- */
+static void Dump( AstObject *this_object, AstChannel *channel, int *status ) {
+/*
+*  Name:
+*     Dump
+
+*  Purpose:
+*     Dump function for UnitNormMap objects.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     void Dump( AstObject *this, AstChannel *channel, int *status )
+
+*  Description:
+*     This function implements the Dump function which writes out data
+*     for the UnitNormMap class to an output Channel.
+
+*  Parameters:
+*     this
+*        Pointer to the UnitNormMap whose data are being written.
+*     channel
+*        Pointer to the Channel to which the data are being written.
+*     status
+*        Pointer to the inherited status variable.
+*/
+
+/* Local Constants: */
+#define COMMENT_LEN 50           /* Maximum length of a comment string */
+#define KEY_LEN 50               /* Maximum length of a keyword */
+
+/* Local Variables: */
+   char buff[ KEY_LEN + 1 ];        /* Buffer for keyword string */
+   char comment[ COMMENT_LEN + 1 ]; /* Buffer for comment string */
+
+/* Check the global error status. */
+   if( !astOK ) return;
+
+/* Obtain a pointer to the UnitNormMap structure. */
+   AstUnitNormMap *this = (AstUnitNormMap *) this_object;
+
+/* Get the length of the centre array. */
+   int ncoord = astGetInvert( this ) ? astGetNout( this ) : astGetNin( this );
+
+/* Write out values representing the instance variables for the
+   UnitNormMap class.  Accompany these with appropriate comment strings,
+   possibly depending on the values being written.*/
+
+/* The centre. */
+   int axis = 0;
+   for( axis = 0; axis < ncoord; axis++ ){
+      (void) sprintf( buff, "Ctr%d", axis + 1 );
+      (void) sprintf( comment, "Centre for axis %d", axis + 1 );
+      astWriteDouble( channel, buff, (this->centre)[ axis ] != 0.0, 0,
+                      (this->centre)[ axis ], comment );
+   }
+
+/* Undefine macros local to this function. */
+#undef COMMENT_LEN
+#undef KEY_LEN
+}
+
+/* Standard class functions. */
+/* ========================= */
+/* Implement the astIsAUnitNormMap and astCheckUnitNormMap functions using the macros
+   defined for this purpose in the "object.h" header file. */
+astMAKE_ISA(UnitNormMap,Mapping)
+astMAKE_CHECK(UnitNormMap)
+
+AstUnitNormMap *astUnitNormMap_( int ncoord, const double centre[], const char *options, int *status, ...) {
+/*
+*++
+*  Name:
+c     astUnitNormMap
+f     AST_UNITNORMMAP
+
+*  Purpose:
+*     Create a UnitNormMap.
+
+*  Type:
+*     Public function.
+
+*  Synopsis:
+c     #include "unitnormmap.h"
+c     AstUnitNormMap *astUnitNormMap( int ncoord, const double centre[],
+c                               const char *options, ... )
+f     RESULT = AST_UNITNORMMAP( NCOORD, CENTRE, OPTIONS, STATUS )
+
+*  Class Membership:
+*     UnitNormMap constructor.
+
+*  Description:
+*     This function creates a new UnitNormMap and optionally initialises its
+*     attributes.
+*
+*     The forward transformation of a UnitNormMap subtracts the specified centre
+*     and then transforms the resulting vector to a unit vector and the vector norm.
+*     The output contains one more coordinate than the input: the initial
+*     Nin outputs are in the same order as the input; the final output is the norm.
+*     If the norm is 0, then the output of the forward transformation is AST__BAD
+*     for each component of the unit vector and 0 for the norm (the final value).
+*
+*     The inverse transformation of a UnitNormMap multiplies each component
+*     of the provided vector by the provided norm and adds the specified centre.
+*     The output contains one fewer coordinate than the input: the initial Nin inputs
+*     are in the same order as the output; the final input is the norm.
+*     If the provided norm is 0 then the other input values are ignored,
+*     and the output vector is the centre.
+*
+*     Example: if centre = [1, -1] then [5, 2] transforms to [4, 3] after subtracting the centre;
+*     the norm is 5, so the output is [0.8, 0.6, 5].
+*
+*     UnitNormMap enables radially symmetric transformations, as follows:
+*     - apply a UnitNormMap to produce a unit vector and norm (radius)
+*     - apply a one-dimensional mapping to the norm (radius), while passing the unit vector unchanged
+*     - apply the same UnitNormMap in the inverse direction to produce the result
+
+*  Parameters:
+c     ncoord
+f     NCOORD = INTEGER (Given)
+*        The number of coordinate values for each point to be
+*        transformed (i.e. the number of dimensions of the space in
+*        which the points will reside). Output will include one additional coordinate.
+c     centre
+f     CENTRE( NCOORD ) = DOUBLE PRECISION (Given)
+*        An array containing the values to be subtracted from the input
+*        coordinates before computing unit vector and norm. A separate
+*        value must be supplied for each coordinate.
+c     options
+f     OPTIONS = CHARACTER * ( * ) (Given)
+c        Pointer to a null-terminated string containing an optional
+c        comma-separated list of attribute assignments to be used for
+c        initialising the new UnitNormMap. The syntax used is identical to
+c        that for the astSet function and may include "printf" format
+c        specifiers identified by "%" symbols in the normal way.
+f        A character string containing an optional comma-separated
+f        list of attribute assignments to be used for initialising the
+f        new UnitNormMap. The syntax used is identical to that for the
+f        AST_SET routine.
+c     ...
+c        If the "options" string contains "%" format specifiers, then
+c        an optional list of additional arguments may follow it in
+c        order to supply values to be substituted for these
+c        specifiers. The rules for supplying these are identical to
+c        those for the astSet function (and for the C "printf"
+c        function).
+f     STATUS = INTEGER (Given and Returned)
+f        The global status.
+
+*  Returned Value:
+c     astUnitNormMap()
+f     AST_UNITNORMMAP = INTEGER
+*        A pointer to the new UnitNormMap.
+
+*  Notes:
+*     - A null Object pointer (AST__NULL) will be returned if this
+c     function is invoked with the AST error status set, or if it
+f     function is invoked with STATUS set to an error value, or if it
+*     should fail for any reason.
+
+*  Status Handling:
+*     The protected interface to this function includes an extra
+*     parameter at the end of the parameter list descirbed above. This
+*     parameter is a pointer to the integer inherited status
+*     variable: "int *status".
+
+*--
+*/
+
+/* Get a pointer to the thread specific global data structure. */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   astGET_GLOBALS(NULL);
+
+/* Check the global status. */
+   if( !astOK ) return NULL;
+
+/* Initialise the UnitNormMap, allocating memory and initialising the
+   virtual function table as well if necessary. */
+   AstUnitNormMap *new = astInitUnitNormMap( NULL, sizeof( AstUnitNormMap ), !class_init, &class_vtab,
+                        "UnitNormMap", ncoord, centre );
+
+/* If successful, note that the virtual function table has been
+   initialised. */
+   if( astOK ) {
+      class_init = 1;
+
+/* Obtain the variable argument list and pass it along with the options string
+   to the astVSet method to initialise the new UnitNormMap's attributes. */
+      va_list args;
+      va_start( args, status );
+      astVSet( new, options, NULL, args );
+      va_end( args );
+
+/* If an error occurred, clean up by deleting the new object. */
+      if( !astOK ) new = astDelete( new );
+   }
+
+/* Return a pointer to the new UnitNormMap. */
+   return new;
+}
+
+AstUnitNormMap *astUnitNormMapId_( int ncoord, const double centre[],
+                             const char *options, ... ) {
+/*
+*  Name:
+*     astUnitNormMapId_
+
+*  Purpose:
+*     Create a UnitNormMap.
+
+*  Type:
+*     Private function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     AstUnitNormMap *astUnitNormMapId_( int ncoord, const double centre[],
+*                                  const char *options, ... )
+
+*  Class Membership:
+*     UnitNormMap constructor.
+
+*  Description:
+*     This function implements the external (public) interface to the
+*     astUnitNormMap constructor function. It returns an ID value (instead
+*     of a true C pointer) to external users, and must be provided
+*     because astUnitNormMap_ has a variable argument list which cannot be
+*     encapsulated in a macro (where this conversion would otherwise
+*     occur).
+*
+*     The variable argument list also prevents this function from
+*     invoking astUnitNormMap_ directly, so it must be a re-implementation
+*     of it in all respects, except for the final conversion of the
+*     result to an ID value.
+
+*  Parameters:
+*     As for astUnitNormMap_.
+
+*  Returned Value:
+*     The ID value associated with the new UnitNormMap.
+*/
+
+   int *status;                  /* Pointer to inherited status value */
+
+/* Get a pointer to the inherited status value. */
+   status = astGetStatusPtr;
+
+/* Get a pointer to the thread specific global data structure. */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   astGET_GLOBALS(NULL);
+
+/* Check the global status. */
+   if( !astOK ) return NULL;
+
+/* Initialise the UnitNormMap, allocating memory and initialising the
+   virtual function table as well if necessary. */
+   AstUnitNormMap *new = astInitUnitNormMap( NULL, sizeof( AstUnitNormMap ), !class_init, &class_vtab,
+                          "UnitNormMap", ncoord, centre );
+
+/* If successful, note that the virtual function table has been
+   initialised. */
+   if( astOK ) {
+      class_init = 1;
+
+/* Obtain the variable argument list and pass it along with the options string
+   to the astVSet method to initialise the new UnitNormMap's attributes. */
+      va_list args;                /* Variable argument list */
+      va_start( args, options );
+      astVSet( new, options, NULL, args );
+      va_end( args );
+
+/* If an error occurred, clean up by deleting the new object. */
+      if( !astOK ) new = astDelete( new );
+   }
+
+/* Return an ID value for the new UnitNormMap. */
+   return astMakeId( new );
+}
+
+AstUnitNormMap *astInitUnitNormMap_( void *mem, size_t size, int init,
+                              AstUnitNormMapVtab *vtab, const char *name,
+                              int ncoord, const double *centre, int *status ) {
+/*
+*+
+*  Name:
+*     astInitUnitNormMap
+
+*  Purpose:
+*     Initialise a UnitNormMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     AstUnitNormMap *astInitUnitNormMap( void *mem, size_t size, int init,
+*                                   AstUnitNormMapVtab *vtab, const char *name,
+*                                   int ncoord, const double *centre )
+
+*  Class Membership:
+*     UnitNormMap initialiser.
+
+*  Description:
+*     This function is provided for use by class implementations to initialise
+*     a new UnitNormMap object. It allocates memory (if necessary) to accommodate
+*     the UnitNormMap plus any additional data associated with the derived class.
+*     It then initialises a UnitNormMap structure at the start of this memory. If
+*     the "init" flag is set, it also initialises the contents of a virtual
+*     function table for a UnitNormMap at the start of the memory passed via the
+*     "vtab" parameter.
+
+*  Parameters:
+*     mem
+*        A pointer to the memory in which the UnitNormMap is to be initialised.
+*        This must be of sufficient size to accommodate the UnitNormMap data
+*        (sizeof(UnitNormMap)) plus any data used by the derived class. If a value
+*        of NULL is given, this function will allocate the memory itself using
+*        the "size" parameter to determine its size.
+*     size
+*        The amount of memory used by the UnitNormMap (plus derived class data).
+*        This will be used to allocate memory if a value of NULL is given for
+*        the "mem" parameter. This value is also stored in the UnitNormMap
+*        structure, so a valid value must be supplied even if not required for
+*        allocating memory.
+*     init
+*        A logical flag indicating if the UnitNormMap's virtual function table is
+*        to be initialised. If this value is non-zero, the virtual function
+*        table will be initialised by this function.
+*     vtab
+*        Pointer to the start of the virtual function table to be associated
+*        with the new UnitNormMap.
+*     name
+*        Pointer to a constant null-terminated character string which contains
+*        the name of the class to which the new object belongs (it is this
+*        pointer value that will subsequently be returned by the astGetClass
+*        method).
+*     ncoord
+*        The number of coordinate values per point.
+*     centre
+*        Pointer to an array of centres, one for each coordinate.
+
+*  Returned Value:
+*     A pointer to the new UnitNormMap.
+
+*  Notes:
+*     -  A null pointer will be returned if this function is invoked with the
+*     global error status set, or if it should fail for any reason.
+*-
+*/
+
+/* Local Variables: */
+   AstUnitNormMap *new;            /* Pointer to new UnitNormMap */
+
+/* Check the global status. */
+   if( !astOK ) return NULL;
+
+/* Check centre */
+   if( ncoord <= 0 ){
+      astError( AST__BADSM, "The centre must have at least one axis", status );
+      return NULL;
+   }
+
+/* If necessary, initialise the virtual function table. */
+   if( init ) astInitUnitNormMapVtab( vtab, name );
+
+/* Initialise. */
+   new = NULL;
+
+/* Initialise a Mapping structure (the parent class) as the first component
+   within the UnitNormMap structure, allocating memory if necessary. Specify that
+   the Mapping should be defined in both the forward and inverse directions. */
+   new = (AstUnitNormMap *) astInitMapping( mem, size, 0,
+                                         (AstMappingVtab *) vtab, name,
+                                         ncoord, ncoord+1, 1, 1 );
+
+   if( astOK ) {
+
+/* Initialise the UnitNormMap data. */
+/* ---------------------------- */
+/* Allocate memory to hold the centre for each axis. */
+      new->centre = (double *) astMalloc( sizeof(double)*(size_t)ncoord );
+
+/* Check the pointers can be used */
+      if( astOK ){
+
+/* Store the centre for each axis. */
+         int axis = 0;
+         for( axis = 0; axis < ncoord; axis++ ){
+            (new->centre)[ axis ] = centre ? centre[ axis ] : AST__BAD;
+         }
+
+      }
+
+/* If an error occurred, clean up by deleting the new UnitNormMap. */
+      if( !astOK ) new = astDelete( new );
+   }
+
+/* Return a pointer to the new UnitNormMap. */
+   return new;
+}
+
+AstUnitNormMap *astLoadUnitNormMap_( void *mem, size_t size,
+                               AstUnitNormMapVtab *vtab, const char *name,
+                               AstChannel *channel, int *status ) {
+/*
+*+
+*  Name:
+*     astLoadUnitNormMap
+
+*  Purpose:
+*     Load a UnitNormMap.
+
+*  Type:
+*     Protected function.
+
+*  Synopsis:
+*     #include "unitnormmap.h"
+*     AstUnitNormMap *astLoadUnitNormMap( void *mem, size_t size,
+*                                   AstUnitNormMapVtab *vtab, const char *name,
+*                                   AstChannel *channel )
+
+*  Class Membership:
+*     UnitNormMap loader.
+
+*  Description:
+*     This function is provided to load a new UnitNormMap using data read
+*     from a Channel. It first loads the data used by the parent class
+*     (which allocates memory if necessary) and then initialises a
+*     UnitNormMap structure in this memory, using data read from the input
+*     Channel.
+*
+*     If the "init" flag is set, it also initialises the contents of a
+*     virtual function table for a UnitNormMap at the start of the memory
+*     passed via the "vtab" parameter.
+
+
+*  Parameters:
+*     mem
+*        A pointer to the memory into which the UnitNormMap is to be
+*        loaded.  This must be of sufficient size to accommodate the
+*        UnitNormMap data (sizeof(UnitNormMap)) plus any data used by derived
+*        classes. If a value of NULL is given, this function will
+*        allocate the memory itself using the "size" parameter to
+*        determine its size.
+*     size
+*        The amount of memory used by the UnitNormMap (plus derived class
+*        data).  This will be used to allocate memory if a value of
+*        NULL is given for the "mem" parameter. This value is also
+*        stored in the UnitNormMap structure, so a valid value must be
+*        supplied even if not required for allocating memory.
+*
+*        If the "vtab" parameter is NULL, the "size" value is ignored
+*        and sizeof(AstUnitNormMap) is used instead.
+*     vtab
+*        Pointer to the start of the virtual function table to be
+*        associated with the new UnitNormMap. If this is NULL, a pointer
+*        to the (static) virtual function table for the UnitNormMap class
+*        is used instead.
+*     name
+*        Pointer to a constant null-terminated character string which
+*        contains the name of the class to which the new object
+*        belongs (it is this pointer value that will subsequently be
+*        returned by the astGetClass method).
+*
+*        If the "vtab" parameter is NULL, the "name" value is ignored
+*        and a pointer to the string "UnitNormMap" is used instead.
+
+*  Returned Value:
+*     A pointer to the new UnitNormMap.
+
+*  Notes:
+*     - A null pointer will be returned if this function is invoked
+*     with the global error status set, or if it should fail for any
+*     reason.
+*-
+*/
+
+/* Local Constants. */
+#define KEY_LEN 50               /* Maximum length of a keyword */
+
+/* Local Variables: */
+   char buff[ KEY_LEN + 1 ];     /* Buffer for keyword string */
+   int axis;                     /* Axis index */
+   int ncoord;                   /* Length of the centre array */
+
+/* Get a pointer to the thread specific global data structure. */
+   astDECLARE_GLOBALS            /* Pointer to thread-specific global data */
+   astGET_GLOBALS(channel);
+
+/* Initialise. */
+   AstUnitNormMap *new = NULL;
+
+/* Check the global error status. */
+   if( !astOK ) return new;
+
+/* If a NULL virtual function table has been supplied, then this is
+   the first loader to be invoked for this UnitNormMap. In this case the
+   UnitNormMap belongs to this class, so supply appropriate values to be
+   passed to the parent class loader (and its parent, etc.). */
+   if( !vtab ) {
+      size = sizeof( AstUnitNormMap );
+      vtab = &class_vtab;
+      name = "UnitNormMap";
+
+/* If required, initialise the virtual function table for this class. */
+      if( !class_init ) {
+         astInitUnitNormMapVtab( vtab, name );
+         class_init = 1;
+      }
+   }
+
+/* Invoke the parent class loader to load data for all the ancestral
+   classes of the current one, returning a pointer to the resulting
+   partly-built UnitNormMap. */
+   new = astLoadMapping( mem, size, (AstMappingVtab *) vtab, name,
+                         channel );
+
+/* Get the length of the centre array = the number of inputs in the 
+   forward direction. */
+   ncoord = 0;
+   if ( astGetInvert( (AstMapping *) new ) ){
+      ncoord = astGetNout( (AstMapping *) new );
+   } else {
+      ncoord = astGetNin( (AstMapping *) new );
+   }
+   if( ncoord <= 0 && astOK ){
+      astError( AST__LDERR, "The UnitNormMap has %d axes - it must have at least one.", 
+                status, ncoord );
+      return NULL;
+   }
+
+/* Allocate memory to hold the centre. */
+   new->centre = (double *) astMalloc( sizeof(double)*(size_t)ncoord );
+
+/* Read input data. */
+/* ================ */
+/* Request the input Channel to read all the input data appropriate to
+   this class into the internal "values list". */
+   if( astOK ) {
+      astReadClassData( channel, "UnitNormMap" );
+
+/* Now read each individual data item from this list and use it to
+   initialise the appropriate instance variable(s) for this class. */
+
+/* The centre. */
+      for( axis = 0; axis < ncoord; axis++ ){
+         (void) sprintf( buff, "ctr%d", axis + 1 );
+         (new->centre)[ axis ] = astReadDouble( channel, buff, 0.0 );
+      }
+   }
+
+/* If an error occurred, clean up by deleting the new UnitNormMap. */
+   if( !astOK ) new = astDelete( new );
+
+/* Return the new UnitNormMap pointer. */
+   return new;
+
+/* Undefine macros local to this function. */
+#undef KEY_LEN
+}
+
+/* Virtual function interfaces. */
+/* ============================ */
+/* These provide the external interface to the virtual functions defined by
+   this class. Each simply checks the global error status and then locates and
+   executes the appropriate member function, using the function pointer stored
+   in the object's virtual function table (this pointer is located using the
+   astMEMBER macro defined in "object.h").
+
+   Note that the member function may not be the one defined here, as it may
+   have been over-ridden by a derived class. However, it should still have the
+   same interface. */