Merged revisions 62380,62382-62383 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r62380 | christian.heimes | 2008-04-19 01:13:07 +0200 (Sat, 19 Apr 2008) | 3 lines

  I finally got the time to update and merge Mark's and my trunk-math branch. The patch is collaborated work of Mark Dickinson and me. It was mostly done a few months ago. The patch fixes a lot of loose ends and edge cases related to operations with NaN, INF, very small values and complex math.

  The patch also adds acosh, asinh, atanh, log1p and copysign to all platforms. Finally it fixes differences between platforms like different results or exceptions for edge cases. Have fun :)
........
  r62382 | christian.heimes | 2008-04-19 01:40:40 +0200 (Sat, 19 Apr 2008) | 2 lines

  Added new files to Windows project files
  More Windows related fixes are coming soon
........
  r62383 | christian.heimes | 2008-04-19 01:49:11 +0200 (Sat, 19 Apr 2008) | 1 line

  Stupid me. Py_RETURN_NAN should actually return something ...
........

1 files changed, 886 insertions, 133 deletions

diff --git a/Modules/cmathmodule.c b/Modules/cmathmodule.c
index ec48ce8..8e3c31e 100644
--- a/Modules/cmathmodule.c
+++ b/Modules/cmathmodule.c
@@ -3,31 +3,172 @@
 /* much code borrowed from mathmodule.c */
 
 #include "Python.h"
+/* we need DBL_MAX, DBL_MIN, DBL_EPSILON, DBL_MANT_DIG and FLT_RADIX from
+   float.h.  We assume that FLT_RADIX is either 2 or 16. */
+#include <float.h>
 
-#ifndef M_PI
-#define M_PI (3.141592653589793239)
+#if (FLT_RADIX != 2 && FLT_RADIX != 16)
+#error "Modules/cmathmodule.c expects FLT_RADIX to be 2 or 16"
 #endif
 
-/* First, the C functions that do the real work */
+#ifndef M_LN2
+#define M_LN2 (0.6931471805599453094) /* natural log of 2 */
+#endif
+
+#ifndef M_LN10
+#define M_LN10 (2.302585092994045684) /* natural log of 10 */
+#endif
 
-/* constants */
-static Py_complex c_one = {1., 0.};
-static Py_complex c_half = {0.5, 0.};
-static Py_complex c_i = {0., 1.};
-static Py_complex c_halfi = {0., 0.5};
+/*
+   CM_LARGE_DOUBLE is used to avoid spurious overflow in the sqrt, log,
+   inverse trig and inverse hyperbolic trig functions.  Its log is used in the
+   evaluation of exp, cos, cosh, sin, sinh, tan, and tanh to avoid unecessary
+   overflow.
+ */
+
+#define CM_LARGE_DOUBLE (DBL_MAX/4.)
+#define CM_SQRT_LARGE_DOUBLE (sqrt(CM_LARGE_DOUBLE))
+#define CM_LOG_LARGE_DOUBLE (log(CM_LARGE_DOUBLE))
+#define CM_SQRT_DBL_MIN (sqrt(DBL_MIN))
+
+/* 
+   CM_SCALE_UP is an odd integer chosen such that multiplication by
+   2**CM_SCALE_UP is sufficient to turn a subnormal into a normal.
+   CM_SCALE_DOWN is (-(CM_SCALE_UP+1)/2).  These scalings are used to compute
+   square roots accurately when the real and imaginary parts of the argument
+   are subnormal.
+*/
+
+#if FLT_RADIX==2
+#define CM_SCALE_UP (2*(DBL_MANT_DIG/2) + 1)
+#elif FLT_RADIX==16
+#define CM_SCALE_UP (4*DBL_MANT_DIG+1)
+#endif
+#define CM_SCALE_DOWN (-(CM_SCALE_UP+1)/2)
 
 /* forward declarations */
-static Py_complex c_log(Py_complex);
-static Py_complex c_prodi(Py_complex);
+static Py_complex c_asinh(Py_complex);
+static Py_complex c_atanh(Py_complex);
+static Py_complex c_cosh(Py_complex);
+static Py_complex c_sinh(Py_complex);
 static Py_complex c_sqrt(Py_complex);
+static Py_complex c_tanh(Py_complex);
 static PyObject * math_error(void);
 
+/* Code to deal with special values (infinities, NaNs, etc.). */
+
+/* special_type takes a double and returns an integer code indicating
+   the type of the double as follows:
+*/
+
+enum special_types {
+	ST_NINF,	/* 0, negative infinity */
+	ST_NEG,		/* 1, negative finite number (nonzero) */
+	ST_NZERO,	/* 2, -0. */
+	ST_PZERO,	/* 3, +0. */
+	ST_POS,		/* 4, positive finite number (nonzero) */
+	ST_PINF,	/* 5, positive infinity */
+	ST_NAN,		/* 6, Not a Number */
+};
+
+static enum special_types
+special_type(double d)
+{
+	if (Py_IS_FINITE(d)) {
+		if (d != 0) {
+			if (copysign(1., d) == 1.)
+				return ST_POS;
+			else
+				return ST_NEG;
+		}
+		else {
+			if (copysign(1., d) == 1.)
+				return ST_PZERO;
+			else
+				return ST_NZERO;
+		}
+	}
+	if (Py_IS_NAN(d))
+		return ST_NAN;
+	if (copysign(1., d) == 1.)
+		return ST_PINF;
+	else
+		return ST_NINF;
+}
+
+#define SPECIAL_VALUE(z, table)						\
+	if (!Py_IS_FINITE((z).real) || !Py_IS_FINITE((z).imag)) {	\
+		errno = 0;                                              \
+		return table[special_type((z).real)]	                \
+			    [special_type((z).imag)];			\
+	}
+
+#define P Py_MATH_PI
+#define P14 0.25*Py_MATH_PI
+#define P12 0.5*Py_MATH_PI
+#define P34 0.75*Py_MATH_PI
+#ifdef MS_WINDOWS
+/* On Windows HUGE_VAL is an extern variable and not a constant. Since the
+   special value arrays need a constant we have to roll our own infinity
+   and nan. */
+#  define INF (DBL_MAX*DBL_MAX)
+#  define N (INF*0.)
+#else
+#  define INF Py_HUGE_VAL
+#  define N Py_NAN
+#endif /* MS_WINDOWS */
+#define U -9.5426319407711027e33 /* unlikely value, used as placeholder */
+
+/* First, the C functions that do the real work.  Each of the c_*
+   functions computes and returns the C99 Annex G recommended result
+   and also sets errno as follows: errno = 0 if no floating-point
+   exception is associated with the result; errno = EDOM if C99 Annex
+   G recommends raising divide-by-zero or invalid for this result; and
+   errno = ERANGE where the overflow floating-point signal should be
+   raised.
+*/
+
+static Py_complex acos_special_values[7][7] = {
+  {{P34,INF},{P,INF}, {P,INF}, {P,-INF}, {P,-INF}, {P34,-INF},{N,INF}},
+  {{P12,INF},{U,U},   {U,U},   {U,U},    {U,U},    {P12,-INF},{N,N}},
+  {{P12,INF},{U,U},   {P12,0.},{P12,-0.},{U,U},    {P12,-INF},{P12,N}},
+  {{P12,INF},{U,U},   {P12,0.},{P12,-0.},{U,U},    {P12,-INF},{P12,N}},
+  {{P12,INF},{U,U},   {U,U},   {U,U},    {U,U},    {P12,-INF},{N,N}},
+  {{P14,INF},{0.,INF},{0.,INF},{0.,-INF},{0.,-INF},{P14,-INF},{N,INF}},
+  {{N,INF},  {N,N},   {N,N},   {N,N},    {N,N},    {N,-INF},  {N,N}}
+};
 
 static Py_complex
-c_acos(Py_complex x)
+c_acos(Py_complex z)
 {
-	return c_neg(c_prodi(c_log(c_sum(x,c_prod(c_i,
-		    c_sqrt(c_diff(c_one,c_prod(x,x))))))));
+	Py_complex s1, s2, r;
+
+	SPECIAL_VALUE(z, acos_special_values);
+
+	if (fabs(z.real) > CM_LARGE_DOUBLE || fabs(z.imag) > CM_LARGE_DOUBLE) {
+		/* avoid unnecessary overflow for large arguments */
+		r.real = atan2(fabs(z.imag), z.real);
+		/* split into cases to make sure that the branch cut has the
+		   correct continuity on systems with unsigned zeros */
+		if (z.real < 0.) {
+			r.imag = -copysign(log(hypot(z.real/2., z.imag/2.)) +
+					   M_LN2*2., z.imag);
+		} else {
+			r.imag = copysign(log(hypot(z.real/2., z.imag/2.)) +
+					  M_LN2*2., -z.imag);
+		}
+	} else {
+		s1.real = 1.-z.real;
+		s1.imag = -z.imag;
+		s1 = c_sqrt(s1);
+		s2.real = 1.+z.real;
+		s2.imag = z.imag;
+		s2 = c_sqrt(s2);
+		r.real = 2.*atan2(s1.real, s2.real);
+		r.imag = asinh(s2.real*s1.imag - s2.imag*s1.real);
+	}
+	errno = 0;
+	return r;
 }
 
 PyDoc_STRVAR(c_acos_doc,
@@ -36,14 +177,39 @@ PyDoc_STRVAR(c_acos_doc,
 "Return the arc cosine of x.");
 
 
+static Py_complex acosh_special_values[7][7] = {
+  {{INF,-P34},{INF,-P}, {INF,-P}, {INF,P}, {INF,P}, {INF,P34},{INF,N}},
+  {{INF,-P12},{U,U},    {U,U},    {U,U},   {U,U},   {INF,P12},{N,N}},
+  {{INF,-P12},{U,U},    {0.,-P12},{0.,P12},{U,U},   {INF,P12},{N,N}},
+  {{INF,-P12},{U,U},    {0.,-P12},{0.,P12},{U,U},   {INF,P12},{N,N}},
+  {{INF,-P12},{U,U},    {U,U},    {U,U},   {U,U},   {INF,P12},{N,N}},
+  {{INF,-P14},{INF,-0.},{INF,-0.},{INF,0.},{INF,0.},{INF,P14},{INF,N}},
+  {{INF,N},   {N,N},    {N,N},    {N,N},   {N,N},   {INF,N},  {N,N}}
+};
+
 static Py_complex
-c_acosh(Py_complex x)
+c_acosh(Py_complex z)
 {
-	Py_complex z;
-	z = c_sqrt(c_half);
-	z = c_log(c_prod(z, c_sum(c_sqrt(c_sum(x,c_one)),
-				  c_sqrt(c_diff(x,c_one)))));
-	return c_sum(z, z);
+	Py_complex s1, s2, r;
+
+	SPECIAL_VALUE(z, acosh_special_values);
+
+	if (fabs(z.real) > CM_LARGE_DOUBLE || fabs(z.imag) > CM_LARGE_DOUBLE) {
+		/* avoid unnecessary overflow for large arguments */
+		r.real = log(hypot(z.real/2., z.imag/2.)) + M_LN2*2.;
+		r.imag = atan2(z.imag, z.real);
+	} else {
+		s1.real = z.real - 1.;
+		s1.imag = z.imag;
+		s1 = c_sqrt(s1);
+		s2.real = z.real + 1.;
+		s2.imag = z.imag;
+		s2 = c_sqrt(s2);
+		r.real = asinh(s1.real*s2.real + s1.imag*s2.imag);
+		r.imag = 2.*atan2(s1.imag, s2.real);
+	}
+	errno = 0;
+	return r;
 }
 
 PyDoc_STRVAR(c_acosh_doc,
@@ -53,14 +219,16 @@ PyDoc_STRVAR(c_acosh_doc,
 
 
 static Py_complex
-c_asin(Py_complex x)
+c_asin(Py_complex z)
 {
-	/* -i * log[(sqrt(1-x**2) + i*x] */
-	const Py_complex squared = c_prod(x, x);
-	const Py_complex sqrt_1_minus_x_sq = c_sqrt(c_diff(c_one, squared));
-        return c_neg(c_prodi(c_log(
-        		c_sum(sqrt_1_minus_x_sq, c_prodi(x))
-		    )       )     );
+	/* asin(z) = -i asinh(iz) */
+	Py_complex s, r;
+	s.real = -z.imag;
+	s.imag = z.real;
+	s = c_asinh(s);
+	r.real = s.imag;
+	r.imag = -s.real;
+	return r;
 }
 
 PyDoc_STRVAR(c_asin_doc,
@@ -69,14 +237,44 @@ PyDoc_STRVAR(c_asin_doc,
 "Return the arc sine of x.");
 
 
+static Py_complex asinh_special_values[7][7] = {
+  {{-INF,-P14},{-INF,-0.},{-INF,-0.},{-INF,0.},{-INF,0.},{-INF,P14},{-INF,N}},
+  {{-INF,-P12},{U,U},     {U,U},     {U,U},    {U,U},    {-INF,P12},{N,N}},
+  {{-INF,-P12},{U,U},     {-0.,-0.}, {-0.,0.}, {U,U},    {-INF,P12},{N,N}},
+  {{INF,-P12}, {U,U},     {0.,-0.},  {0.,0.},  {U,U},    {INF,P12}, {N,N}},
+  {{INF,-P12}, {U,U},     {U,U},     {U,U},    {U,U},    {INF,P12}, {N,N}},
+  {{INF,-P14}, {INF,-0.}, {INF,-0.}, {INF,0.}, {INF,0.}, {INF,P14}, {INF,N}},
+  {{INF,N},    {N,N},     {N,-0.},   {N,0.},   {N,N},    {INF,N},   {N,N}}
+};
+
 static Py_complex
-c_asinh(Py_complex x)
+c_asinh(Py_complex z)
 {
-	Py_complex z;
-	z = c_sqrt(c_half);
-	z = c_log(c_prod(z, c_sum(c_sqrt(c_sum(x, c_i)),
-				  c_sqrt(c_diff(x, c_i)))));
-	return c_sum(z, z);
+	Py_complex s1, s2, r;
+
+	SPECIAL_VALUE(z, asinh_special_values);
+
+	if (fabs(z.real) > CM_LARGE_DOUBLE || fabs(z.imag) > CM_LARGE_DOUBLE) {
+		if (z.imag >= 0.) {
+			r.real = copysign(log(hypot(z.real/2., z.imag/2.)) +
+					  M_LN2*2., z.real);
+		} else {
+			r.real = -copysign(log(hypot(z.real/2., z.imag/2.)) +
+					   M_LN2*2., -z.real);
+		}
+		r.imag = atan2(z.imag, fabs(z.real));
+	} else {
+		s1.real = 1.+z.imag;
+		s1.imag = -z.real;
+		s1 = c_sqrt(s1);
+		s2.real = 1.-z.imag;
+		s2.imag = z.real;
+		s2 = c_sqrt(s2);
+		r.real = asinh(s1.real*s2.imag-s2.real*s1.imag);
+		r.imag = atan2(z.imag, s1.real*s2.real-s1.imag*s2.imag);
+	}
+	errno = 0;
+	return r;
 }
 
 PyDoc_STRVAR(c_asinh_doc,
@@ -86,9 +284,37 @@ PyDoc_STRVAR(c_asinh_doc,
 
 
 static Py_complex
-c_atan(Py_complex x)
+c_atan(Py_complex z)
 {
-	return c_prod(c_halfi,c_log(c_quot(c_sum(c_i,x),c_diff(c_i,x))));
+	/* atan(z) = -i atanh(iz) */
+	Py_complex s, r;
+	s.real = -z.imag;
+	s.imag = z.real;
+	s = c_atanh(s);
+	r.real = s.imag;
+	r.imag = -s.real;
+	return r;
+}
+
+/* Windows screws up atan2 for inf and nan */
+static double
+c_atan2(Py_complex z)
+{
+	if (Py_IS_NAN(z.real) || Py_IS_NAN(z.imag))
+		return Py_NAN;
+	if (Py_IS_INFINITY(z.imag)) {
+		if (Py_IS_INFINITY(z.real)) {
+			if (copysign(1., z.real) == 1.)
+				/* atan2(+-inf, +inf) == +-pi/4 */
+				return copysign(0.25*Py_MATH_PI, z.imag);
+			else
+				/* atan2(+-inf, -inf) == +-pi*3/4 */
+				return copysign(0.75*Py_MATH_PI, z.imag);
+		}
+		/* atan2(+-inf, x) == +-pi/2 for finite x */
+		return copysign(0.5*Py_MATH_PI, z.imag);
+	}
+	return atan2(z.imag, z.real);
 }
 
 PyDoc_STRVAR(c_atan_doc,
@@ -97,10 +323,61 @@ PyDoc_STRVAR(c_atan_doc,
 "Return the arc tangent of x.");
 
 
+static Py_complex atanh_special_values[7][7] = {
+  {{-0.,-P12},{-0.,-P12},{-0.,-P12},{-0.,P12},{-0.,P12},{-0.,P12},{-0.,N}},
+  {{-0.,-P12},{U,U},     {U,U},     {U,U},    {U,U},    {-0.,P12},{N,N}},
+  {{-0.,-P12},{U,U},     {-0.,-0.}, {-0.,0.}, {U,U},    {-0.,P12},{-0.,N}},
+  {{0.,-P12}, {U,U},     {0.,-0.},  {0.,0.},  {U,U},    {0.,P12}, {0.,N}},
+  {{0.,-P12}, {U,U},     {U,U},     {U,U},    {U,U},    {0.,P12}, {N,N}},
+  {{0.,-P12}, {0.,-P12}, {0.,-P12}, {0.,P12}, {0.,P12}, {0.,P12}, {0.,N}},
+  {{0.,-P12}, {N,N},     {N,N},     {N,N},    {N,N},    {0.,P12}, {N,N}}
+};
+
 static Py_complex
-c_atanh(Py_complex x)
+c_atanh(Py_complex z)
 {
-	return c_prod(c_half,c_log(c_quot(c_sum(c_one,x),c_diff(c_one,x))));
+	Py_complex r;
+	double ay, h;
+
+	SPECIAL_VALUE(z, atanh_special_values);
+
+	/* Reduce to case where z.real >= 0., using atanh(z) = -atanh(-z). */
+	if (z.real < 0.) {
+		return c_neg(c_atanh(c_neg(z)));
+	}
+
+	ay = fabs(z.imag);
+	if (z.real > CM_SQRT_LARGE_DOUBLE || ay > CM_SQRT_LARGE_DOUBLE) {
+		/*
+		   if abs(z) is large then we use the approximation
+		   atanh(z) ~ 1/z +/- i*pi/2 (+/- depending on the sign
+		   of z.imag)
+		*/
+		h = hypot(z.real/2., z.imag/2.);  /* safe from overflow */
+		r.real = z.real/4./h/h;
+		/* the two negations in the next line cancel each other out
+		   except when working with unsigned zeros: they're there to
+		   ensure that the branch cut has the correct continuity on
+		   systems that don't support signed zeros */
+		r.imag = -copysign(Py_MATH_PI/2., -z.imag);
+		errno = 0;
+	} else if (z.real == 1. && ay < CM_SQRT_DBL_MIN) {
+		/* C99 standard says:  atanh(1+/-0.) should be inf +/- 0i */
+		if (ay == 0.) {
+			r.real = INF;
+			r.imag = z.imag;
+			errno = EDOM;
+		} else {
+			r.real = -log(sqrt(ay)/sqrt(hypot(ay, 2.)));
+			r.imag = copysign(atan2(2., -ay)/2, z.imag);
+			errno = 0;
+		}
+	} else {
+		r.real = log1p(4.*z.real/((1-z.real)*(1-z.real) + ay*ay))/4.;
+		r.imag = -atan2(-2.*z.imag, (1-z.real)*(1+z.real) - ay*ay)/2.;
+		errno = 0;
+	}
+	return r;
 }
 
 PyDoc_STRVAR(c_atanh_doc,
@@ -110,11 +387,13 @@ PyDoc_STRVAR(c_atanh_doc,
 
 
 static Py_complex
-c_cos(Py_complex x)
+c_cos(Py_complex z)
 {
+	/* cos(z) = cosh(iz) */
 	Py_complex r;
-	r.real = cos(x.real)*cosh(x.imag);
-	r.imag = -sin(x.real)*sinh(x.imag);
+	r.real = -z.imag;
+	r.imag = z.real;
+	r = c_cosh(r);
 	return r;
 }
 
@@ -124,12 +403,64 @@ PyDoc_STRVAR(c_cos_doc,
 "Return the cosine of x.");
 
 
+/* cosh(infinity + i*y) needs to be dealt with specially */
+static Py_complex cosh_special_values[7][7] = {
+  {{INF,N},{U,U},{INF,0.}, {INF,-0.},{U,U},{INF,N},{INF,N}},
+  {{N,N},  {U,U},{U,U},    {U,U},    {U,U},{N,N},  {N,N}},
+  {{N,0.}, {U,U},{1.,0.},  {1.,-0.}, {U,U},{N,0.}, {N,0.}},
+  {{N,0.}, {U,U},{1.,-0.}, {1.,0.},  {U,U},{N,0.}, {N,0.}},
+  {{N,N},  {U,U},{U,U},    {U,U},    {U,U},{N,N},  {N,N}},
+  {{INF,N},{U,U},{INF,-0.},{INF,0.}, {U,U},{INF,N},{INF,N}},
+  {{N,N},  {N,N},{N,0.},   {N,0.},   {N,N},{N,N},  {N,N}}
+};
+
 static Py_complex
-c_cosh(Py_complex x)
+c_cosh(Py_complex z)
 {
 	Py_complex r;
-	r.real = cos(x.imag)*cosh(x.real);
-	r.imag = sin(x.imag)*sinh(x.real);
+	double x_minus_one;
+
+	/* special treatment for cosh(+/-inf + iy) if y is not a NaN */
+	if (!Py_IS_FINITE(z.real) || !Py_IS_FINITE(z.imag)) {
+		if (Py_IS_INFINITY(z.real) && Py_IS_FINITE(z.imag) &&
+		    (z.imag != 0.)) {
+			if (z.real > 0) {
+				r.real = copysign(INF, cos(z.imag));
+				r.imag = copysign(INF, sin(z.imag));
+			}
+			else {
+				r.real = copysign(INF, cos(z.imag));
+				r.imag = -copysign(INF, sin(z.imag));
+			}
+		}
+		else {
+			r = cosh_special_values[special_type(z.real)]
+				               [special_type(z.imag)];
+		}
+		/* need to set errno = EDOM if y is +/- infinity and x is not
+		   a NaN */
+		if (Py_IS_INFINITY(z.imag) && !Py_IS_NAN(z.real))
+			errno = EDOM;
+		else
+			errno = 0;
+		return r;
+	}
+
+	if (fabs(z.real) > CM_LOG_LARGE_DOUBLE) {
+		/* deal correctly with cases where cosh(z.real) overflows but
+		   cosh(z) does not. */
+		x_minus_one = z.real - copysign(1., z.real);
+		r.real = cos(z.imag) * cosh(x_minus_one) * Py_MATH_E;
+		r.imag = sin(z.imag) * sinh(x_minus_one) * Py_MATH_E;
+	} else {
+		r.real = cos(z.imag) * cosh(z.real);
+		r.imag = sin(z.imag) * sinh(z.real);
+	}
+	/* detect overflow, and set errno accordingly */
+	if (Py_IS_INFINITY(r.real) || Py_IS_INFINITY(r.imag))
+		errno = ERANGE;
+	else
+		errno = 0;
 	return r;
 }
 
@@ -139,13 +470,65 @@ PyDoc_STRVAR(c_cosh_doc,
 "Return the hyperbolic cosine of x.");
 
 
+/* exp(infinity + i*y) and exp(-infinity + i*y) need special treatment for
+   finite y */
+static Py_complex exp_special_values[7][7] = {
+  {{0.,0.},{U,U},{0.,-0.}, {0.,0.}, {U,U},{0.,0.},{0.,0.}},
+  {{N,N},  {U,U},{U,U},    {U,U},   {U,U},{N,N},  {N,N}},
+  {{N,N},  {U,U},{1.,-0.}, {1.,0.}, {U,U},{N,N},  {N,N}},
+  {{N,N},  {U,U},{1.,-0.}, {1.,0.}, {U,U},{N,N},  {N,N}},
+  {{N,N},  {U,U},{U,U},    {U,U},   {U,U},{N,N},  {N,N}},
+  {{INF,N},{U,U},{INF,-0.},{INF,0.},{U,U},{INF,N},{INF,N}},
+  {{N,N},  {N,N},{N,-0.},  {N,0.},  {N,N},{N,N},  {N,N}}
+};
+
 static Py_complex
-c_exp(Py_complex x)
+c_exp(Py_complex z)
 {
 	Py_complex r;
-	double l = exp(x.real);
-	r.real = l*cos(x.imag);
-	r.imag = l*sin(x.imag);
+	double l;
+
+	if (!Py_IS_FINITE(z.real) || !Py_IS_FINITE(z.imag)) {
+		if (Py_IS_INFINITY(z.real) && Py_IS_FINITE(z.imag)
+		    && (z.imag != 0.)) {
+			if (z.real > 0) {
+				r.real = copysign(INF, cos(z.imag));
+				r.imag = copysign(INF, sin(z.imag));
+			}
+			else {
+				r.real = copysign(0., cos(z.imag));
+				r.imag = copysign(0., sin(z.imag));
+			}
+		}
+		else {
+			r = exp_special_values[special_type(z.real)]
+				              [special_type(z.imag)];
+		}
+		/* need to set errno = EDOM if y is +/- infinity and x is not
+		   a NaN and not -infinity */
+		if (Py_IS_INFINITY(z.imag) &&
+		    (Py_IS_FINITE(z.real) ||
+		     (Py_IS_INFINITY(z.real) && z.real > 0)))
+			errno = EDOM;
+		else
+			errno = 0;
+		return r;
+	}
+
+	if (z.real > CM_LOG_LARGE_DOUBLE) {
+		l = exp(z.real-1.);
+		r.real = l*cos(z.imag)*Py_MATH_E;
+		r.imag = l*sin(z.imag)*Py_MATH_E;
+	} else {
+		l = exp(z.real);
+		r.real = l*cos(z.imag);
+		r.imag = l*sin(z.imag);
+	}
+	/* detect overflow, and set errno accordingly */
+	if (Py_IS_INFINITY(r.real) || Py_IS_INFINITY(r.imag))
+		errno = ERANGE;
+	else
+		errno = 0;
 	return r;
 }
 
@@ -155,24 +538,97 @@ PyDoc_STRVAR(c_exp_doc,
 "Return the exponential value e**x.");
 
 
+static Py_complex log_special_values[7][7] = {
+  {{INF,-P34},{INF,-P}, {INF,-P},  {INF,P},  {INF,P}, {INF,P34}, {INF,N}},
+  {{INF,-P12},{U,U},    {U,U},     {U,U},    {U,U},   {INF,P12}, {N,N}},
+  {{INF,-P12},{U,U},    {-INF,-P}, {-INF,P}, {U,U},   {INF,P12}, {N,N}},
+  {{INF,-P12},{U,U},    {-INF,-0.},{-INF,0.},{U,U},   {INF,P12}, {N,N}},
+  {{INF,-P12},{U,U},    {U,U},     {U,U},    {U,U},   {INF,P12}, {N,N}},
+  {{INF,-P14},{INF,-0.},{INF,-0.}, {INF,0.}, {INF,0.},{INF,P14}, {INF,N}},
+  {{INF,N},   {N,N},    {N,N},     {N,N},    {N,N},   {INF,N},   {N,N}}
+};
+
 static Py_complex
-c_log(Py_complex x)
+c_log(Py_complex z)
 {
+	/*
+	   The usual formula for the real part is log(hypot(z.real, z.imag)).
+	   There are four situations where this formula is potentially
+	   problematic:
+
+	   (1) the absolute value of z is subnormal.  Then hypot is subnormal,
+	   so has fewer than the usual number of bits of accuracy, hence may
+	   have large relative error.  This then gives a large absolute error
+	   in the log.  This can be solved by rescaling z by a suitable power
+	   of 2.
+
+	   (2) the absolute value of z is greater than DBL_MAX (e.g. when both
+	   z.real and z.imag are within a factor of 1/sqrt(2) of DBL_MAX)
+	   Again, rescaling solves this.
+
+	   (3) the absolute value of z is close to 1.  In this case it's
+	   difficult to achieve good accuracy, at least in part because a
+	   change of 1ulp in the real or imaginary part of z can result in a
+	   change of billions of ulps in the correctly rounded answer.
+
+	   (4) z = 0.  The simplest thing to do here is to call the
+	   floating-point log with an argument of 0, and let its behaviour
+	   (returning -infinity, signaling a floating-point exception, setting
+	   errno, or whatever) determine that of c_log.  So the usual formula
+	   is fine here.
+
+	 */
+
 	Py_complex r;
-	double l = hypot(x.real,x.imag);
-	r.imag = atan2(x.imag, x.real);
-	r.real = log(l);
+	double ax, ay, am, an, h;
+
+	SPECIAL_VALUE(z, log_special_values);
+
+	ax = fabs(z.real);
+	ay = fabs(z.imag);
+
+	if (ax > CM_LARGE_DOUBLE || ay > CM_LARGE_DOUBLE) {
+		r.real = log(hypot(ax/2., ay/2.)) + M_LN2;
+	} else if (ax < DBL_MIN && ay < DBL_MIN) {
+		if (ax > 0. || ay > 0.) {
+			/* catch cases where hypot(ax, ay) is subnormal */
+			r.real = log(hypot(ldexp(ax, DBL_MANT_DIG),
+				 ldexp(ay, DBL_MANT_DIG))) - DBL_MANT_DIG*M_LN2;
+		}
+		else {
+			/* log(+/-0. +/- 0i) */
+			r.real = -INF;
+			r.imag = atan2(z.imag, z.real);
+			errno = EDOM;
+			return r;
+		}
+	} else {
+		h = hypot(ax, ay);
+		if (0.71 <= h && h <= 1.73) {
+			am = ax > ay ? ax : ay;  /* max(ax, ay) */
+			an = ax > ay ? ay : ax;  /* min(ax, ay) */
+			r.real = log1p((am-1)*(am+1)+an*an)/2.;
+		} else {
+			r.real = log(h);
+		}
+	}
+	r.imag = atan2(z.imag, z.real);
+	errno = 0;
 	return r;
 }
 
 
 static Py_complex
-c_log10(Py_complex x)
+c_log10(Py_complex z)
 {
 	Py_complex r;
-	double l = hypot(x.real,x.imag);
-	r.imag = atan2(x.imag, x.real)/log(10.);
-	r.real = log10(l);
+	int errno_save;
+
+	r = c_log(z);
+	errno_save = errno; /* just in case the divisions affect errno */
+	r.real = r.real / M_LN10;
+	r.imag = r.imag / M_LN10;
+	errno = errno_save;
 	return r;
 }
 
@@ -182,23 +638,16 @@ PyDoc_STRVAR(c_log10_doc,
 "Return the base-10 logarithm of x.");
 
 
-/* internal function not available from Python */
-static Py_complex
-c_prodi(Py_complex x)
-{
-	Py_complex r;
-	r.real = -x.imag;
-	r.imag = x.real;
-	return r;
-}
-
-
 static Py_complex
-c_sin(Py_complex x)
+c_sin(Py_complex z)
 {
-	Py_complex r;
-	r.real = sin(x.real) * cosh(x.imag);
-	r.imag = cos(x.real) * sinh(x.imag);
+	/* sin(z) = -i sin(iz) */
+	Py_complex s, r;
+	s.real = -z.imag;
+	s.imag = z.real;
+	s = c_sinh(s);
+	r.real = s.imag;
+	r.imag = -s.real;
 	return r;
 }
 
@@ -208,12 +657,63 @@ PyDoc_STRVAR(c_sin_doc,
 "Return the sine of x.");
 
 
+/* sinh(infinity + i*y) needs to be dealt with specially */
+static Py_complex sinh_special_values[7][7] = {
+  {{INF,N},{U,U},{-INF,-0.},{-INF,0.},{U,U},{INF,N},{INF,N}},
+  {{N,N},  {U,U},{U,U},     {U,U},    {U,U},{N,N},  {N,N}},
+  {{0.,N}, {U,U},{-0.,-0.}, {-0.,0.}, {U,U},{0.,N}, {0.,N}},
+  {{0.,N}, {U,U},{0.,-0.},  {0.,0.},  {U,U},{0.,N}, {0.,N}},
+  {{N,N},  {U,U},{U,U},     {U,U},    {U,U},{N,N},  {N,N}},
+  {{INF,N},{U,U},{INF,-0.}, {INF,0.}, {U,U},{INF,N},{INF,N}},
+  {{N,N},  {N,N},{N,-0.},   {N,0.},   {N,N},{N,N},  {N,N}}
+};
+
 static Py_complex
-c_sinh(Py_complex x)
+c_sinh(Py_complex z)
 {
 	Py_complex r;
-	r.real = cos(x.imag) * sinh(x.real);
-	r.imag = sin(x.imag) * cosh(x.real);
+	double x_minus_one;
+
+	/* special treatment for sinh(+/-inf + iy) if y is finite and
+	   nonzero */
+	if (!Py_IS_FINITE(z.real) || !Py_IS_FINITE(z.imag)) {
+		if (Py_IS_INFINITY(z.real) && Py_IS_FINITE(z.imag)
+		    && (z.imag != 0.)) {
+			if (z.real > 0) {
+				r.real = copysign(INF, cos(z.imag));
+				r.imag = copysign(INF, sin(z.imag));
+			}
+			else {
+				r.real = -copysign(INF, cos(z.imag));
+				r.imag = copysign(INF, sin(z.imag));
+			}
+		}
+		else {
+			r = sinh_special_values[special_type(z.real)]
+				               [special_type(z.imag)];
+		}
+		/* need to set errno = EDOM if y is +/- infinity and x is not
+		   a NaN */
+		if (Py_IS_INFINITY(z.imag) && !Py_IS_NAN(z.real))
+			errno = EDOM;
+		else
+			errno = 0;
+		return r;
+	}
+
+	if (fabs(z.real) > CM_LOG_LARGE_DOUBLE) {
+		x_minus_one = z.real - copysign(1., z.real);
+		r.real = cos(z.imag) * sinh(x_minus_one) * Py_MATH_E;
+		r.imag = sin(z.imag) * cosh(x_minus_one) * Py_MATH_E;
+	} else {
+		r.real = cos(z.imag) * sinh(z.real);
+		r.imag = sin(z.imag) * cosh(z.real);
+	}
+	/* detect overflow, and set errno accordingly */
+	if (Py_IS_INFINITY(r.real) || Py_IS_INFINITY(r.imag))
+		errno = ERANGE;
+	else
+		errno = 0;
 	return r;
 }
 
@@ -223,29 +723,80 @@ PyDoc_STRVAR(c_sinh_doc,
 "Return the hyperbolic sine of x.");
 
 
+static Py_complex sqrt_special_values[7][7] = {
+  {{INF,-INF},{0.,-INF},{0.,-INF},{0.,INF},{0.,INF},{INF,INF},{N,INF}},
+  {{INF,-INF},{U,U},    {U,U},    {U,U},   {U,U},   {INF,INF},{N,N}},
+  {{INF,-INF},{U,U},    {0.,-0.}, {0.,0.}, {U,U},   {INF,INF},{N,N}},
+  {{INF,-INF},{U,U},    {0.,-0.}, {0.,0.}, {U,U},   {INF,INF},{N,N}},
+  {{INF,-INF},{U,U},    {U,U},    {U,U},   {U,U},   {INF,INF},{N,N}},
+  {{INF,-INF},{INF,-0.},{INF,-0.},{INF,0.},{INF,0.},{INF,INF},{INF,N}},
+  {{INF,-INF},{N,N},    {N,N},    {N,N},   {N,N},   {INF,INF},{N,N}}
+};
+
 static Py_complex
-c_sqrt(Py_complex x)
+c_sqrt(Py_complex z)
 {
+	/*
+	   Method: use symmetries to reduce to the case when x = z.real and y
+	   = z.imag are nonnegative.  Then the real part of the result is
+	   given by
+
+	     s = sqrt((x + hypot(x, y))/2)
+
+	   and the imaginary part is
+
+	     d = (y/2)/s
+
+	   If either x or y is very large then there's a risk of overflow in
+	   computation of the expression x + hypot(x, y).  We can avoid this
+	   by rewriting the formula for s as:
+
+	     s = 2*sqrt(x/8 + hypot(x/8, y/8))
+
+	   This costs us two extra multiplications/divisions, but avoids the
+	   overhead of checking for x and y large.
+
+	   If both x and y are subnormal then hypot(x, y) may also be
+	   subnormal, so will lack full precision.  We solve this by rescaling
+	   x and y by a sufficiently large power of 2 to ensure that x and y
+	   are normal.
+	*/
+
+
 	Py_complex r;
 	double s,d;
-	if (x.real == 0. && x.imag == 0.)
-		r = x;
-	else {
-		s = sqrt(0.5*(fabs(x.real) + hypot(x.real,x.imag)));
-		d = 0.5*x.imag/s;
-		if (x.real > 0.) {
-			r.real = s;
-			r.imag = d;
-		}
-		else if (x.imag >= 0.) {
-			r.real = d;
-			r.imag = s;
-		}
-		else {
-			r.real = -d;
-			r.imag = -s;
-		}
+	double ax, ay;
+
+	SPECIAL_VALUE(z, sqrt_special_values);
+
+	if (z.real == 0. && z.imag == 0.) {
+		r.real = 0.;
+		r.imag = z.imag;
+		return r;
+	}
+
+	ax = fabs(z.real);
+	ay = fabs(z.imag);
+
+	if (ax < DBL_MIN && ay < DBL_MIN && (ax > 0. || ay > 0.)) {
+		/* here we catch cases where hypot(ax, ay) is subnormal */
+		ax = ldexp(ax, CM_SCALE_UP);
+		s = ldexp(sqrt(ax + hypot(ax, ldexp(ay, CM_SCALE_UP))),
+			  CM_SCALE_DOWN);
+	} else {
+		ax /= 8.;
+		s = 2.*sqrt(ax + hypot(ax, ay/8.));
+	}
+	d = ay/(2.*s);
+
+	if (z.real >= 0.) {
+		r.real = s;
+		r.imag = copysign(d, z.imag);
+	} else {
+		r.real = d;
+		r.imag = copysign(s, z.imag);
 	}
+	errno = 0;
 	return r;
 }
 
@@ -256,23 +807,15 @@ PyDoc_STRVAR(c_sqrt_doc,
 
 
 static Py_complex
-c_tan(Py_complex x)
+c_tan(Py_complex z)
 {
-	Py_complex r;
-	double sr,cr,shi,chi;
-	double rs,is,rc,ic;
-	double d;
-	sr = sin(x.real);
-	cr = cos(x.real);
-	shi = sinh(x.imag);
-	chi = cosh(x.imag);
-	rs = sr * chi;
-	is = cr * shi;
-	rc = cr * chi;
-	ic = -sr * shi;
-	d = rc*rc + ic * ic;
-	r.real = (rs*rc + is*ic) / d;
-	r.imag = (is*rc - rs*ic) / d;
+	/* tan(z) = -i tanh(iz) */
+	Py_complex s, r;
+	s.real = -z.imag;
+	s.imag = z.real;
+	s = c_tanh(s);
+	r.real = s.imag;
+	r.imag = -s.real;
 	return r;
 }
 
@@ -282,24 +825,78 @@ PyDoc_STRVAR(c_tan_doc,
 "Return the tangent of x.");
 
 
+/* tanh(infinity + i*y) needs to be dealt with specially */
+static Py_complex tanh_special_values[7][7] = {
+  {{-1.,0.},{U,U},{-1.,-0.},{-1.,0.},{U,U},{-1.,0.},{-1.,0.}},
+  {{N,N},   {U,U},{U,U},    {U,U},   {U,U},{N,N},   {N,N}},
+  {{N,N},   {U,U},{-0.,-0.},{-0.,0.},{U,U},{N,N},   {N,N}},
+  {{N,N},   {U,U},{0.,-0.}, {0.,0.}, {U,U},{N,N},   {N,N}},
+  {{N,N},   {U,U},{U,U},    {U,U},   {U,U},{N,N},   {N,N}},
+  {{1.,0.}, {U,U},{1.,-0.}, {1.,0.}, {U,U},{1.,0.}, {1.,0.}},
+  {{N,N},   {N,N},{N,-0.},  {N,0.},  {N,N},{N,N},   {N,N}}
+};
+
 static Py_complex
-c_tanh(Py_complex x)
+c_tanh(Py_complex z)
 {
+	/* Formula:
+
+	   tanh(x+iy) = (tanh(x)(1+tan(y)^2) + i tan(y)(1-tanh(x))^2) /
+	   (1+tan(y)^2 tanh(x)^2)
+
+	   To avoid excessive roundoff error, 1-tanh(x)^2 is better computed
+	   as 1/cosh(x)^2.  When abs(x) is large, we approximate 1-tanh(x)^2
+	   by 4 exp(-2*x) instead, to avoid possible overflow in the
+	   computation of cosh(x).
+
+	*/
+
 	Py_complex r;
-	double si,ci,shr,chr;
-	double rs,is,rc,ic;
-	double d;
-	si = sin(x.imag);
-	ci = cos(x.imag);
-	shr = sinh(x.real);
-	chr = cosh(x.real);
-	rs = ci * shr;
-	is = si * chr;
-	rc = ci * chr;
-	ic = si * shr;
-	d = rc*rc + ic*ic;
-	r.real = (rs*rc + is*ic) / d;
-	r.imag = (is*rc - rs*ic) / d;
+	double tx, ty, cx, txty, denom;
+
+	/* special treatment for tanh(+/-inf + iy) if y is finite and
+	   nonzero */
+	if (!Py_IS_FINITE(z.real) || !Py_IS_FINITE(z.imag)) {
+		if (Py_IS_INFINITY(z.real) && Py_IS_FINITE(z.imag)
+		    && (z.imag != 0.)) {
+			if (z.real > 0) {
+				r.real = 1.0;
+				r.imag = copysign(0.,
+						  2.*sin(z.imag)*cos(z.imag));
+			}
+			else {
+				r.real = -1.0;
+				r.imag = copysign(0.,
+						  2.*sin(z.imag)*cos(z.imag));
+			}
+		}
+		else {
+			r = tanh_special_values[special_type(z.real)]
+				               [special_type(z.imag)];
+		}
+		/* need to set errno = EDOM if z.imag is +/-infinity and
+		   z.real is finite */
+		if (Py_IS_INFINITY(z.imag) && Py_IS_FINITE(z.real))
+			errno = EDOM;
+		else
+			errno = 0;
+		return r;
+	}
+
+	/* danger of overflow in 2.*z.imag !*/
+	if (fabs(z.real) > CM_LOG_LARGE_DOUBLE) {
+		r.real = copysign(1., z.real);
+		r.imag = 4.*sin(z.imag)*cos(z.imag)*exp(-2.*fabs(z.real));
+	} else {
+		tx = tanh(z.real);
+		ty = tan(z.imag);
+		cx = 1./cosh(z.real);
+		txty = tx*ty;
+		denom = 1. + txty*txty;
+		r.real = tx*(1.+ty*ty)/denom;
+		r.imag = ((ty/denom)*cx)*cx;
+	}
+	errno = 0;
 	return r;
 }
 
@@ -308,6 +905,7 @@ PyDoc_STRVAR(c_tanh_doc,
 "\n"
 "Return the hyperbolic tangent of x.");
 
+
 static PyObject *
 cmath_log(PyObject *self, PyObject *args)
 {
@@ -325,7 +923,6 @@ cmath_log(PyObject *self, PyObject *args)
 	PyFPE_END_PROTECT(x)
 	if (errno != 0)
 		return math_error();
-	Py_ADJUST_ERANGE2(x.real, x.imag);
 	return PyComplex_FromCComplex(x);
 }
 
@@ -351,18 +948,24 @@ math_error(void)
 static PyObject *
 math_1(PyObject *args, Py_complex (*func)(Py_complex))
 {
-	Py_complex x;
+	Py_complex x,r ;
 	if (!PyArg_ParseTuple(args, "D", &x))
 		return NULL;
 	errno = 0;
-	PyFPE_START_PROTECT("complex function", return 0)
-	x = (*func)(x);
-	PyFPE_END_PROTECT(x)
-	Py_ADJUST_ERANGE2(x.real, x.imag);
-	if (errno != 0)
-		return math_error();
-	else
-		return PyComplex_FromCComplex(x);
+	PyFPE_START_PROTECT("complex function", return 0);
+	r = (*func)(x);
+	PyFPE_END_PROTECT(r);
+	if (errno == EDOM) {
+		PyErr_SetString(PyExc_ValueError, "math domain error");
+		return NULL;
+	}
+	else if (errno == ERANGE) {
+		PyErr_SetString(PyExc_OverflowError, "math range error");
+		return NULL;
+	}
+	else {
+		return PyComplex_FromCComplex(r);
+	}
 }
 
 #define FUNC1(stubname, func) \
@@ -386,6 +989,151 @@ FUNC1(cmath_sqrt, c_sqrt)
 FUNC1(cmath_tan, c_tan)
 FUNC1(cmath_tanh, c_tanh)
 
+static PyObject *
+cmath_phase(PyObject *self, PyObject *args)
+{
+	Py_complex z;
+	double phi;
+	if (!PyArg_ParseTuple(args, "D:phase", &z))
+		return NULL;
+	errno = 0;
+	PyFPE_START_PROTECT("arg function", return 0)
+	phi = c_atan2(z);
+	PyFPE_END_PROTECT(r)
+	if (errno != 0)
+		return math_error();
+	else
+		return PyFloat_FromDouble(phi);
+}
+
+PyDoc_STRVAR(cmath_phase_doc,
+"phase(z) -> float\n\n\
+Return argument, also known as the phase angle, of a complex.");
+
+static PyObject *
+cmath_polar(PyObject *self, PyObject *args)
+{
+	Py_complex z;
+	double r, phi;
+	if (!PyArg_ParseTuple(args, "D:polar", &z))
+		return NULL;
+	PyFPE_START_PROTECT("polar function", return 0)
+	phi = c_atan2(z); /* should not cause any exception */
+	r = c_abs(z); /* sets errno to ERANGE on overflow;  otherwise 0 */
+	PyFPE_END_PROTECT(r)
+	if (errno != 0)
+		return math_error();
+	else
+		return Py_BuildValue("dd", r, phi);
+}
+
+PyDoc_STRVAR(cmath_polar_doc,
+"polar(z) -> r: float, phi: float\n\n\
+Convert a complex from rectangular coordinates to polar coordinates. r is\n\
+the distance from 0 and phi the phase angle.");
+
+/*
+  rect() isn't covered by the C99 standard, but it's not too hard to
+  figure out 'spirit of C99' rules for special value handing:
+
+    rect(x, t) should behave like exp(log(x) + it) for positive-signed x
+    rect(x, t) should behave like -exp(log(-x) + it) for negative-signed x
+    rect(nan, t) should behave like exp(nan + it), except that rect(nan, 0)
+      gives nan +- i0 with the sign of the imaginary part unspecified.
+
+*/
+
+static Py_complex rect_special_values[7][7] = {
+  {{INF,N},{U,U},{-INF,0.},{-INF,-0.},{U,U},{INF,N},{INF,N}},
+  {{N,N},  {U,U},{U,U},    {U,U},     {U,U},{N,N},  {N,N}},
+  {{0.,0.},{U,U},{-0.,0.}, {-0.,-0.}, {U,U},{0.,0.},{0.,0.}},
+  {{0.,0.},{U,U},{0.,-0.}, {0.,0.},   {U,U},{0.,0.},{0.,0.}},
+  {{N,N},  {U,U},{U,U},    {U,U},     {U,U},{N,N},  {N,N}},
+  {{INF,N},{U,U},{INF,-0.},{INF,0.},  {U,U},{INF,N},{INF,N}},
+  {{N,N},  {N,N},{N,0.},   {N,0.},    {N,N},{N,N},  {N,N}}
+};
+
+static PyObject *
+cmath_rect(PyObject *self, PyObject *args)
+{
+	Py_complex z;
+	double r, phi;
+	if (!PyArg_ParseTuple(args, "dd:rect", &r, &phi))
+		return NULL;
+	errno = 0;
+	PyFPE_START_PROTECT("rect function", return 0)
+
+	/* deal with special values */
+	if (!Py_IS_FINITE(r) || !Py_IS_FINITE(phi)) {
+		/* if r is +/-infinity and phi is finite but nonzero then
+		   result is (+-INF +-INF i), but we need to compute cos(phi)
+		   and sin(phi) to figure out the signs. */
+		if (Py_IS_INFINITY(r) && (Py_IS_FINITE(phi)
+					  && (phi != 0.))) {
+			if (r > 0) {
+				z.real = copysign(INF, cos(phi));
+				z.imag = copysign(INF, sin(phi));
+			}
+			else {
+				z.real = -copysign(INF, cos(phi));
+				z.imag = -copysign(INF, sin(phi));
+			}
+		}
+		else {
+			z = rect_special_values[special_type(r)]
+				               [special_type(phi)];
+		}
+		/* need to set errno = EDOM if r is a nonzero number and phi
+		   is infinite */
+		if (r != 0. && !Py_IS_NAN(r) && Py_IS_INFINITY(phi))
+			errno = EDOM;
+		else
+			errno = 0;
+	}
+	else {
+		z.real = r * cos(phi);
+		z.imag = r * sin(phi);
+		errno = 0;
+	}
+
+	PyFPE_END_PROTECT(z)
+	if (errno != 0)
+		return math_error();
+	else
+		return PyComplex_FromCComplex(z);
+}
+
+PyDoc_STRVAR(cmath_rect_doc,
+"rect(r, phi) -> z: complex\n\n\
+Convert from polar coordinates to rectangular coordinates.");
+
+static PyObject *
+cmath_isnan(PyObject *self, PyObject *args)
+{
+	Py_complex z;
+	if (!PyArg_ParseTuple(args, "D:isnan", &z))
+		return NULL;
+	return PyBool_FromLong(Py_IS_NAN(z.real) || Py_IS_NAN(z.imag));
+}
+
+PyDoc_STRVAR(cmath_isnan_doc,
+"isnan(z) -> bool\n\
+Checks if the real or imaginary part of z not a number (NaN)");
+
+static PyObject *
+cmath_isinf(PyObject *self, PyObject *args)
+{
+	Py_complex z;
+	if (!PyArg_ParseTuple(args, "D:isnan", &z))
+		return NULL;
+	return PyBool_FromLong(Py_IS_INFINITY(z.real) ||
+			       Py_IS_INFINITY(z.imag));
+}
+
+PyDoc_STRVAR(cmath_isinf_doc,
+"isinf(z) -> bool\n\
+Checks if the real or imaginary part of z is infinite.");
+
 
 PyDoc_STRVAR(module_doc,
 "This module is always available. It provides access to mathematical\n"
@@ -401,8 +1149,13 @@ static PyMethodDef cmath_methods[] = {
 	{"cos",    cmath_cos,   METH_VARARGS, c_cos_doc},
 	{"cosh",   cmath_cosh,  METH_VARARGS, c_cosh_doc},
 	{"exp",    cmath_exp,   METH_VARARGS, c_exp_doc},
+	{"isinf",  cmath_isinf, METH_VARARGS, cmath_isinf_doc},
+	{"isnan",  cmath_isnan, METH_VARARGS, cmath_isnan_doc},
 	{"log",    cmath_log,   METH_VARARGS, cmath_log_doc},
 	{"log10",  cmath_log10, METH_VARARGS, c_log10_doc},
+	{"phase",  cmath_phase, METH_VARARGS, cmath_phase_doc},
+	{"polar",  cmath_polar, METH_VARARGS, cmath_polar_doc},
+	{"rect",   cmath_rect,  METH_VARARGS, cmath_rect_doc},
 	{"sin",    cmath_sin,   METH_VARARGS, c_sin_doc},
 	{"sinh",   cmath_sinh,  METH_VARARGS, c_sinh_doc},
 	{"sqrt",   cmath_sqrt,  METH_VARARGS, c_sqrt_doc},
@@ -421,6 +1174,6 @@ initcmath(void)
 		return;
 
 	PyModule_AddObject(m, "pi",
-                           PyFloat_FromDouble(atan(1.0) * 4.0));
-	PyModule_AddObject(m, "e", PyFloat_FromDouble(exp(1.0)));
+                           PyFloat_FromDouble(Py_MATH_PI));
+	PyModule_AddObject(m, "e", PyFloat_FromDouble(Py_MATH_E));
 }