Linear Algebra and the C Language/a0bv

Install and compile this file in your working directory.

/* ------------------------------------ */
/*  Save as :  c00a.c                   */
/* ------------------------------------ */
#include "v_a.h"
/* ------------------------------------ */
#define   RCA        RC4
/* ------------------------------------ */
void fun(void)
{
double **A             = rPsymmetric_mR(i_mR(RCA,RCA),99.);
double **SqrtA          =               i_mR(RCA,RCA);

double **EigsVector    =               i_mR(RCA,RCA);
double **T_EigsVector  =               i_mR(RCA,RCA);

double **EigsValue     =               i_mR(RCA,RCA);
double **f_EigsValue   =               i_mR(RCA,RCA);

double **T1            =               i_mR(RCA,RCA);
  
  clrscrn();
  printf(" A :");
  p_mR(A, S7,P0, C8); 
  
  eigs_V_mR(A,EigsVector); 
  transpose_mR(EigsVector,T_EigsVector);
      
/* EigsValue : T_EigsVector * A * EigsVector */
  mul_mR(T_EigsVector,A,T1);
  mul_mR(T1,EigsVector,EigsValue);     
  
  printf(" sqrt(A) = EigsVector * sqrt(EigsValue) * T_EigsVector\n");
  f_eigs_mR(sqrt,EigsValue,f_EigsValue);      
     mul_mR(EigsVector,f_EigsValue,T1);
     mul_mR(T1,T_EigsVector,SqrtA);
       p_mR(SqrtA,S10,P4,C8);    
  
  printf(" A = sqrt(A) * sqrt(A)");  
  mul_mR(SqrtA,SqrtA,A);
  p_mR(A, S7,P0, C8);   
   
  f_mR(A);
  f_mR(SqrtA);
    
  f_mR(EigsVector);
  f_mR(T_EigsVector);
  
  f_mR(EigsValue);
  f_mR(f_EigsValue);    
     
  f_mR(T1);
}
/* ------------------------------------ */
int main(void)
{
time_t t;

  srand(time(&t));

do
{
  fun();

} while(stop_w());

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

Screen output example:

                                                                                       
 A :
  +8103     -21     +95     +90 
    -21    +888     -98     +58 
    +95     -98   +6438     +18 
    +90     +58     +18   +4773 

 sqrt(A) = EigsVector * sqrt(EigsValue) * T_EigsVector

  +90.0130    -0.1739    +0.5567    +0.5659 
   -0.1739   +29.7797    -0.8906    +0.5888 
   +0.5567    -0.8906   +80.2302    +0.1220 
   +0.5659    +0.5888    +0.1220   +69.0820 

 A = sqrt(A) * sqrt(A)
  +8103     -21     +95     +90 
    -21    +888     -98     +58 
    +95     -98   +6438     +18 
    +90     +58     +18   +4773 


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