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