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/*
* iemmatrix
*
* objects for manipulating simple matrices
* mostly refering to matlab/octave matrix functions
*
* Copyright (c) IOhannes m zmölnig, forum::für::umläute
* IEM, Graz, Austria
*
* For information on usage and redistribution, and for a DISCLAIMER OF ALL
* WARRANTIES, see the file, "LICENSE.txt," in this distribution.
*
*/
#include "iemmatrix.h"
/* mtx_gauss */
/*
* gauss elimination of a matrix (without semi-pivoting)
*/
static t_class *mtx_gauss_class;
static void mtx_gauss_xch(t_matrixfloat*a, t_matrixfloat*b, int count){
while(count--){
t_matrixfloat dummy=*a;
*a++=*b;
*b++=dummy;
}
}
static void mtx_gauss_mulsub(t_matrixfloat*a, t_matrixfloat*b, int count, t_matrixfloat f){
t_matrixfloat f2=1./f;
while(count--){
t_matrixfloat dummy=(f* (*b) - *a++)*f2;
*b++=dummy;
}
}
static void mtx_gauss_matrix(t_matrix *x, t_symbol *s, int argc, t_atom *argv)
{
/* maybe we should do this in double or long double ? */
int row=atom_getfloat(argv);
int col=atom_getfloat(argv+1);
int i, j;
const t_matrixfloat singrange = 1.0e-10;
t_matrixfloat *original;
t_matrixfloat *a1, *a2; // dummy pointers
if(row*col+2>argc){
post("mtx_print : sparse matrices not yet supported : use \"mtx_check\"");
return;
}
if (row!=col){
post("mtx_gauss: only square matrices can be gauss eliminated");
return;
}
// reserve memory for outputting afterwards
adjustsize(x, row, row);
original=matrix2float(argv);
// Gauss elimination
for(i=0; i<row; i++) {
int nz = 0;
a1=original+i*(col+1);
for(j=i; j<row; j++){
const t_matrixfloat f=*a1;
if((f>singrange)||(f<-singrange)){
nz=j;
break;
}
a1+=col;
}
//if(nz)
{
// exchange rows "nz" and "i"
if(nz != i)mtx_gauss_xch(original+i*col+i, original+nz*col+i, col-i);
//
for(j=i+1; j<row; j++){
t_matrixfloat f=0.;
a1=original+i*(col+1);
a2=original+j*col+i;
if(*a2){
f=*a1 / *a2;
mtx_gauss_mulsub(a1, a2, col-i, f);
}
}
}
}
// 3. output the matrix
// 3a convert the floatbuf to an atombuf;
float2matrix(x->atombuffer, original);
// 3c output the atombuf;
matrix_bang(x);
}
static void *mtx_gauss_new(t_symbol *s, int argc, t_atom *argv)
{
t_matrix *x = (t_matrix *)pd_new(mtx_gauss_class);
outlet_new(&x->x_obj, 0);
x->col=x->row=0;
x->atombuffer=0;
return (x);
}
void mtx_gauss_setup(void)
{
mtx_gauss_class = class_new(gensym("mtx_gauss"), (t_newmethod)mtx_gauss_new,
(t_method)matrix_free, sizeof(t_matrix), 0, A_GIMME, 0);
class_addbang (mtx_gauss_class, matrix_bang);
class_addmethod(mtx_gauss_class, (t_method)mtx_gauss_matrix, gensym("matrix"), A_GIMME, 0);
class_sethelpsymbol(mtx_gauss_class, gensym("iemmatrix/mtx_gauss"));
}
void iemtx_gauss_setup(void){
mtx_gauss_setup();
}
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