<!-- manual page source format generated by PolyglotMan v3.2, --> <!-- available at http://polyglotman.sourceforge.net/ --> <html> <head> <title>IM_MATINV(3) manual page</title> </head> <body bgcolor='white'> <a href='#toc'>Table of Contents</a><p> <h2><a name='sect0' href='#toc0'>Name</a></h2> im_matinv, im_matmul, im_mattrn - matrix operations on DOUBLEMASKs <p> <h2><a name='sect1' href='#toc1'>Synopsis</a></h2> <b>#include <vips/vips.h></b> <p> <b>DOUBLEMASK *im_matinv( const DOUBLEMASK *in, const char *name );</b> <p> <b>int im_matinv_inplace( DOUBLEMASK *mat );</b> <p> <b>DOUBLEMASK *im_matmul( in1, in2, name )</b> <br> <b>DOUBLEMASK *in1, *in2;</b> <br> <b>char *name;</b> <p> <b>DOUBLEMASK *im_matcat( in1, in2, name )</b> <br> <b>DOUBLEMASK *in1, *in2;</b> <br> <b>char *name;</b> <p> <b>DOUBLEMASK *im_mattrn( in, name )</b> <br> <b>DOUBLEMASK *in;</b> <br> <b>char *name;</b> <p> <h2><a name='sect2' href='#toc2'>Description</a></h2> These functions treat DOUBLEMASKs as matricies, performing some of the basics of matrix algebra on them. <p> There should be more matrix functions: those implemeneted are just sufficient for the Gallery’s calibration routines. im_matadd, im_matidentity should really be added. <p> None of these functions damage their arguments, except <a href='im_matinv_inplace.3.html'><b>im_matinv_inplace(3)</b></a> . <p> <a href='im_matinv.3.html'><b>im_matinv(3)</b></a> inverts DOUBLEMASK <i>in</i>, returning a new DOUBLEMASK, called <i>name</i>, which contains the inverse of in. If no inverse exists, NULL is returned and <a href='im_error.3.html'><b>im_error(3)</b></a> is called with a diagnostic message. <p> <a href='im_matinv_inplace.3.html'><b>im_matinv_inplace(3)</b></a> is as <a href='im_matinv.3.html'><b>im_matinv(3)</b></a> except that it overwrites its input. <p> <b>im_matmul()</b> multiples the matrices held in in1 and in2, returning their product in a matrix called name. <p> <b>im_matcat()</b> returns a new matrix formed by appending matrix in2 to the end of matrix in1. The two matricies must be the same width. It is useful for combining several im_measure()s into a single matrix. <p> <b>im_mattrn()</b> transposes matrix in, returning the transpose in new matrix called name. <h2><a name='sect3' href='#toc3'>Notes</a></h2> <b>DO NOT</b> use matrix inversion to solve systems of linear equations (SLEs). The routines <a href='im_lu_decomp.3.html'><b>im_lu_decomp(3)</b></a> and <a href='im_lu_solve.3.html'><b>im_lu_solve(3)</b></a> are more efficient, even for a single SLE. <p> <h2><a name='sect4' href='#toc4'>Return Value</a></h2> The functions returns a new DOUBLEMASK on sucess, and NULL on failure. <p> <a href='im_matinv_inplace.3.html'><b>im_matinv_inplace(3)</b></a> returns zero on success, and -1 on failure. <p> <h2><a name='sect5' href='#toc5'>See Also</a></h2> <a href='im_create_dmask.3.html'>im_create_dmask(3)</a> , <a href='im_measure.3.html'>im_measure(3)</a> , etc. <a href='im_lu_decomp.3.html'>im_lu_decomp(3)</a> , <a href='im_lu_solve.3.html'>im_lu_solve(3)</a> <p> <h2><a name='sect6' href='#toc6'>Copyright</a></h2> National Gallery, 1992. Tom Vajzovic, 2006 <h2><a name='sect7' href='#toc7'>Authors</a></h2> J. Cupitt <br> <p>Tom Vajzovic <p> <p> <hr><p> <a name='toc'><b>Table of Contents</b></a><p> <ul> <li><a name='toc0' href='#sect0'>Name</a></li> <li><a name='toc1' href='#sect1'>Synopsis</a></li> <li><a name='toc2' href='#sect2'>Description</a></li> <li><a name='toc3' href='#sect3'>Notes</a></li> <li><a name='toc4' href='#sect4'>Return Value</a></li> <li><a name='toc5' href='#sect5'>SeeAlso</a></li> <li><a name='toc6' href='#sect6'>Copyright</a></li> <li><a name='toc7' href='#sect7'>Authors</a></li> </ul> </body> </html>