Linear Algebra and the C Language/a0gr

Install and compile this file in your working directory.

/* ------------------------------------ */
/*  Save as :  c00d.c                   */
/* ------------------------------------ */
#include "v_a.h"
/* ------------------------------------ */
void fun(int r)
{
double **A            = rsymmetric_mR(   i_mR(r,r),9.);
double **EigsValue    =       eigs_mR(A, i_mR(r,C1));

  clrscrn();
  printf(" Copy/Paste into the octave windows \n\n");
  p_Octave_mR(A,"a",P0);
  printf(" eigs (a,%d)\n",r);
  printf(" rank (a)\n\n");

  printf(" EigsValue:");   
  p_mR(EigsValue, S10,P4,C6);  
   
  f_mR(A);
  f_mR(EigsValue);  
}
/* ------------------------------------ */
int main(void)
{
time_t t;

  srand(time(&t));

do
{
 fun(rp_I(R3)+R2);

} while(stop_w());

  return 0;
}
/* ------------------------------------ */
/* ------------------------------------ */

The rank of a symmetric matrix is equal to the number of non-zero eigenvalues.

Screen output example:

                                                                                       
 Copy/Paste into the octave windows 

 a=[
-5,-8,-8,-5;
-8,-2,+4,-1;
-8,+4,-2,+4;
-5,-1,+4,+7]

 eigs (a,4)
 rank (a)

 EigsValue:
  +13.9555 
  -13.7618 
   -6.9042 
   +4.7105 


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