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The Datafile PD-CD 1 Issue 2
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PDCD-1 - Issue 02.iso
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_utilities
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utilities
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001
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meschach
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!Meschach
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c
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submat
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1994-01-13
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/**************************************************************************
**
** Copyright (C) 1993 David E. Steward & Zbigniew Leyk, all rights reserved.
**
** Meschach Library
**
** This Meschach Library is provided "as is" without any express
** or implied warranty of any kind with respect to this software.
** In particular the authors shall not be liable for any direct,
** indirect, special, incidental or consequential damages arising
** in any way from use of the software.
**
** Everyone is granted permission to copy, modify and redistribute this
** Meschach Library, provided:
** 1. All copies contain this copyright notice.
** 2. All modified copies shall carry a notice stating who
** made the last modification and the date of such modification.
** 3. No charge is made for this software or works derived from it.
** This clause shall not be construed as constraining other software
** distributed on the same medium as this software, nor is a
** distribution fee considered a charge.
**
***************************************************************************/
/* 1.2 submat.c 11/25/87 */
#include <stdio.h>
#include "matrix.h"
static char rcsid[] = "$Id: submat.c,v 1.2 1994/01/13 05:28:12 des Exp $";
/* get_col -- gets a specified column of a matrix and retruns it as a vector */
VEC *get_col(mat,col,vec)
u_int col;
MAT *mat;
VEC *vec;
{
u_int i;
if ( mat==(MAT *)NULL )
error(E_NULL,"get_col");
if ( col >= mat->n )
error(E_RANGE,"get_col");
if ( vec==(VEC *)NULL || vec->dim<mat->m )
vec = v_resize(vec,mat->m);
for ( i=0; i<mat->m; i++ )
vec->ve[i] = mat->me[i][col];
return (vec);
}
/* get_row -- gets a specified row of a matrix and retruns it as a vector */
VEC *get_row(mat,row,vec)
u_int row;
MAT *mat;
VEC *vec;
{
u_int i;
if ( mat==(MAT *)NULL )
error(E_NULL,"get_row");
if ( row >= mat->m )
error(E_RANGE,"get_row");
if ( vec==(VEC *)NULL || vec->dim<mat->n )
vec = v_resize(vec,mat->n);
for ( i=0; i<mat->n; i++ )
vec->ve[i] = mat->me[row][i];
return (vec);
}
/* _set_col -- sets column of matrix to values given in vec (in situ) */
MAT *_set_col(mat,col,vec,i0)
MAT *mat;
VEC *vec;
u_int col,i0;
{
u_int i,lim;
if ( mat==(MAT *)NULL || vec==(VEC *)NULL )
error(E_NULL,"_set_col");
if ( col >= mat->n )
error(E_RANGE,"_set_col");
lim = min(mat->m,vec->dim);
for ( i=i0; i<lim; i++ )
mat->me[i][col] = vec->ve[i];
return (mat);
}
/* _set_row -- sets row of matrix to values given in vec (in situ) */
MAT *_set_row(mat,row,vec,j0)
MAT *mat;
VEC *vec;
u_int row,j0;
{
u_int j,lim;
if ( mat==(MAT *)NULL || vec==(VEC *)NULL )
error(E_NULL,"_set_row");
if ( row >= mat->m )
error(E_RANGE,"_set_row");
lim = min(mat->n,vec->dim);
for ( j=j0; j<lim; j++ )
mat->me[row][j] = vec->ve[j];
return (mat);
}
/* sub_mat -- returns sub-matrix of old which is formed by the rectangle
from (row1,col1) to (row2,col2)
-- Note: storage is shared so that altering the "new"
matrix will alter the "old" matrix */
MAT *sub_mat(old,row1,col1,row2,col2,new)
MAT *old,*new;
u_int row1,col1,row2,col2;
{
u_int i;
if ( old==(MAT *)NULL )
error(E_NULL,"sub_mat");
if ( row1 > row2 || col1 > col2 || row2 >= old->m || col2 >= old->n )
error(E_RANGE,"sub_mat");
if ( new==(MAT *)NULL || new->m < row2-row1+1 )
{
new = NEW(MAT);
new->me = NEW_A(row2-row1+1,Real *);
if ( new==(MAT *)NULL || new->me==(Real **)NULL )
error(E_MEM,"sub_mat");
else if (mem_info_is_on()) {
mem_bytes(TYPE_MAT,0,sizeof(MAT)+
(row2-row1+1)*sizeof(Real *));
}
}
new->m = row2-row1+1;
new->n = col2-col1+1;
new->base = (Real *)NULL;
for ( i=0; i < new->m; i++ )
new->me[i] = (old->me[i+row1]) + col1;
return (new);
}
/* sub_vec -- returns sub-vector which is formed by the elements i1 to i2
-- as for sub_mat, storage is shared */
VEC *sub_vec(old,i1,i2,new)
VEC *old, *new;
int i1, i2;
{
if ( old == (VEC *)NULL )
error(E_NULL,"sub_vec");
if ( i1 > i2 || old->dim < i2 )
error(E_RANGE,"sub_vec");
if ( new == (VEC *)NULL )
new = NEW(VEC);
if ( new == (VEC *)NULL )
error(E_MEM,"sub_vec");
else if (mem_info_is_on()) {
mem_bytes(TYPE_VEC,0,sizeof(VEC));
}
new->dim = i2 - i1 + 1;
new->ve = &(old->ve[i1]);
return new;
}