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diff --git a/doc/html/Tutor/property.html b/doc/html/Tutor/property.html new file mode 100644 index 0000000..9d40d44 --- /dev/null +++ b/doc/html/Tutor/property.html @@ -0,0 +1,169 @@ +<HTML><HEAD> +<TITLE>HDF5 Tutorial - Property Lists +</TITLE> +</HEAD> + +<body bgcolor="#ffffff"> + +<!-- BEGIN MAIN BODY --> + +<A HREF="http://www.ncsa.uiuc.edu/"><img border=0 +src="http://www.ncsa.uiuc.edu/Images/NCSAhome/footerlogo.gif" +width=78 height=27 alt="NCSA"><P></A> + + [ <A HREF="title.html"><I>HDF5 Tutorial Top</I></A> ] +<H1> +<BIG><BIG><BIG><FONT COLOR="#c101cd">Property Lists</FONT> +</BIG></BIG></BIG></H1> + +<hr noshade size=1> + +<BODY> +<!-- +<H2>Contents:</H2> +<UL> + <LI> <A HREF="#def">Definition of Property Lists</A> +</UL> +<HR> +<A NAME="def"> +--> +<P> +The property list interface provides a mechanism for adding functionality +to HDF5 calls, without increasing the number of arguments used +for a given call. +<P> +A property list is a collection of values which can +be passed to various HDF5 functions to control features that +are typically unimportant or whose default values are usually used +(by specifying <code>H5P_DEFAULT</code> / <CODE>H5P_DEFAULT_F</CODE>). +<P> +It supports unusual cases when: + +<UL> +<LI><A HREF="#cf">Creating Files</A> +<LI><A HREF="#fa">Accessing Files</A> +<LI><A HREF="#cd">Creating Datasets</A> +<LI><A HREF="#rdwt">Reading or Writing Data</A> +</UL> + + +<A NAME="cf"> +<H3>Creating Files</H3> +The File Creation property list, H5P_FILE_CREATE, applies to H5Fcreate() +only and is used to control the file metadata which is maintained in the +super block of the file. The parameters that can be modified are: +user-block size, offset and length sizes, symbol table parameters, +and index storage parameters. +<P> +The following example shows how to create a file with 64-bit object +offsets and lengths: +<PRE> + hid_t create_plist; + hid_t file_id; + + create_plist = H5Pcreate(H5P_FILE_CREATE); + H5Pset_sizes(create_plist, 8, 8); + + file_id = H5Fcreate("test.h5", H5F_ACC_TRUNC, + create_plist, H5P_DEFAULT); + . + . + . + H5Fclose(file_id); +</PRE> + +<A NAME="fa"> +<H3>Accessing Files</H3> +The File Access property list, H5P_FILE_ACCESS, applies to H5Fcreate() and +H5Fopen() and is used to control different methods of +performing I/O on files. The different types of I/O are: unbuffered I/O, +buffered I/O, memory I/O, parallel files using MPI I/O, and data alignment. +<P> +Following is an example of using the H5P_FILE_ACCESS property list for creating +HDF5 files with the metadata and data split into different files: +<BR> +[ <A HREF="examples/h5split.c">C program</A> ] + - <code>h5split.c</code><BR> +<P> + +<A NAME="cd"> +<h3>Creating Datasets</H3> +The Dataset Creation property list, H5P_DATASET_CREATE, applies to +H5Dcreate() and controls information on how raw data +is organized on disk and how the raw data is compressed. The dataset API +partitions these terms by layout, compression, and external storage: +<P> +<UL> + <LI>Layout: +<UL> +<LI>H5D_COMPACT: Data is small and can be stored in object header (<I>not + implemented yet</I>). This eliminates disk seek/read requests. +<P> +<LI>H5D_CONTIGUOUS: (default) The data is large, non-extendible, +non-compressible, non-sparse, and can be stored externally. +<P> +<LI>H5D_CHUNKED: The data is large and can be extended in any dimension. +It is partitioned into chunks so each chunk is the same logical size. +Following is an example that uses the H5P_DATASET_CREATE property list to create +a chunked and extendible dataset: +<BR> +[ <A HREF="examples/h5_extend.c">C program</A> ] + - <code>h5_extend.c</code><BR> +<P> +</UL> +<LI>Compression: (gzip compression) +<LI>External Storage Properties: The data must be contiguous to be stored + externally. It allows you to store the data in one or more non-HDF5 files. +Following is an example of using the H5P_DATASET_CREATE property list to +create a dataset in an external file: +<BR> +[ <A HREF="examples/h5_crtextd.c">C program</A> ] + - <code>h5_crtextd.c</code><BR> +<P> +</UL> +</UL> +<A NAME="rdwt"> +<H3>Reading or Writing Data</H3> + +The Data Transfer property list, H5P_DATASET_XFER, is used to control +various aspects of I/O, such as caching hints or collective I/O information. +<P> +The following code sets the maximum size for the type conversion buffer +and background buffer: +<PRE> + plist_xfer = H5Pcreate (H5P_DATASET_XFER); + H5Pset_buffer(plist_xfer, (hsize_t)NX*NY*NZ, NULL, NULL); + status = H5Dread (dataset, H5T_NATIVE_UCHAR, memspace, dataspace, + plist_xfer); +</PRE> +See:<BR> + [ <A HREF="examples/h5_xfer.c">C program</A> ] + - <code> h5_xfer.c</code><BR> + + +<!-- BEGIN FOOTER INFO --> + +<P><hr noshade size=1> +<font face="arial,helvetica" size="-1"> + <a href="http://www.ncsa.uiuc.edu/"><img border=0 + src="http://www.ncsa.uiuc.edu/Images/NCSAhome/footerlogo.gif" + width=78 height=27 alt="NCSA"><br> + The National Center for Supercomputing Applications</A><br> + <a href="http://www.uiuc.edu/">University of Illinois + at Urbana-Champaign</a><br> + <br> +<!-- <A HREF="helpdesk.mail.html"> --> +<A HREF="mailto:hdfhelp@ncsa.uiuc.edu"> +hdfhelp@ncsa.uiuc.edu</A> +<br> +<BR> <H6>Last Modified: February 12, 2001</H6><BR> +<!-- modified by Barbara Jones - bljones@ncsa.uiuc.edu --> +</FONT> +<BR> +<!-- <A HREF="mailto:hdfhelp@ncsa.uiuc.edu"> --> + +</BODY> +</HTML> + + + |