| .TH IM_MATINV 3 "2 May 1991" |
| .SH NAME |
| im_matinv, im_matmul, im_mattrn \- matrix operations on DOUBLEMASKs |
| |
| .SH SYNOPSIS |
| .B #include <vips/vips.h> |
| |
| .B DOUBLEMASK *im_matinv( const DOUBLEMASK *in, const char *name ); |
| |
| .B int im_matinv_inplace( DOUBLEMASK *mat ); |
| |
| .B DOUBLEMASK *im_matmul( in1, in2, name ) |
| .br |
| .B DOUBLEMASK *in1, *in2; |
| .br |
| .B char *name; |
| |
| .B DOUBLEMASK *im_matcat( in1, in2, name ) |
| .br |
| .B DOUBLEMASK *in1, *in2; |
| .br |
| .B char *name; |
| |
| .B DOUBLEMASK *im_mattrn( in, name ) |
| .br |
| .B DOUBLEMASK *in; |
| .br |
| .B char *name; |
| |
| .SH DESCRIPTION |
| These functions treat DOUBLEMASKs as matricies, performing some of the basics |
| of matrix algebra on them. |
| |
| 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. |
| |
| None of these functions damage their arguments, except |
| .BR "im_matinv_inplace(3)" ". |
| |
| .B im_matinv(3) |
| inverts DOUBLEMASK |
| .IR "in" ", |
| returning a new DOUBLEMASK, called |
| .IR "name" ", |
| which contains the inverse of in. If no inverse exists, NULL is returned and |
| .B im_error(3) |
| is called with a diagnostic message. |
| |
| .B im_matinv_inplace(3) |
| is as |
| .B im_matinv(3) |
| except that it overwrites its input. |
| |
| .B im_matmul() |
| multiples the matrices held in in1 and in2, returning their product in a |
| matrix called name. |
| |
| .B im_matcat() |
| 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. |
| |
| .B im_mattrn() |
| transposes matrix in, returning the transpose in new matrix called name. |
| .SH NOTES |
| .B DO NOT |
| use matrix inversion to solve systems of linear equations (SLEs). The |
| routines |
| .B im_lu_decomp(3) |
| and |
| .B im_lu_solve(3) |
| are more efficient, even for a single SLE. |
| |
| .SH RETURN VALUE |
| The functions returns a new DOUBLEMASK on sucess, and NULL on failure. |
| .PP |
| .B im_matinv_inplace(3) |
| returns zero on success, and -1 on failure. |
| |
| .SH SEE\ ALSO |
| im_create_dmask(3), im_measure(3), etc. im_lu_decomp(3), im_lu_solve(3) |
| |
| .SH COPYRIGHT |
| National Gallery, 1992. Tom Vajzovic, 2006 |
| .SH AUTHORS |
| J. Cupitt |
| .br |
| Tom Vajzovic |
| |
