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/* Copyright (C) 2017 - IIT Bombay - FOSSEE
This file must be used under the terms of the CeCILL.
This source file is licensed as described in the file COPYING, which
you should have received as part of this distribution. The terms
are also available at
http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
Author: Sandeep Gupta
Organization: FOSSEE, IIT Bombay
Email: toolbox@scilab.in
*/
/* PROJSPEC function in scilab */
/*
//[S,P,D,index]=projspec(A)
//Spectral characteristics of A at 0
//S = reduced resolvent at 0 (S=-Drazin_inverse(A))
//P = spectral projection at 0
//D = Nilpotent operator at 0
//index = index of the 0 eigenvalue
//!
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "norm.h"
#include "eye.h"
#define eps pow(2,-52)
double dprojspeca(double *inp1,int row,int col,double *out1,double *out2,double *out3){
double tol = pow(10,-6);
int i,j,index;
/*norm(A,1)*/
double nor;
nor = dnorma(inp1,row,col,1);
/* P=eye(A),D=A,S=0*P;index=1; */
if(nor < eps*row*row){
memcpy(out2,inp1,row*col*sizeof(double));
deyea(out2,row,col);
memcpy(out3,inp1,row*col*sizeof(double));
for(i=0;i<row;i++){
for(j=0;j<row;j++){
out1[i*row+j] = 0;
}
}
index = 1;
}
/* rcond(A) */
double *rcon;
rcon = rcond(inp1,row);
if(rcon > tol){
dinverma(inp1,out1,row);
for(i=0;i<row*col;i++){
out2[i]=0;
out3[i]=0;
}
index = 0;
return index;
}
index = 1;
}
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