Linear Algebra and the C Language/a0c7


Install and compile this file in your working directory.

/* ------------------------------------ */
/*  Save as :  c00a.c                   */
/* ------------------------------------ */
#include "v_a.h"
/* ------------------------------------ */
#define   RCA        RC5
/* ------------------------------------ */
/* ------------------------------------ */
void fun(void)
{
double **A             = rEsymmetric_mR(i_mR(RCA,RCA),555.,1E-3);
double **cos_A         =               i_mR(RCA,RCA);

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

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

double **T1            =               i_mR(RCA,RCA);
  
  clrscrn();
  printf(" A :");
  p_mR(A,S10,P4,C6); 

/* ================================================================== */ 
  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(" cos(A) :");
  f_eigs_mR(cos,EigsValue,cos_EigsValue); 
     mul_mR(EigsVector,cos_EigsValue,T1);
     mul_mR(T1,T_EigsVector,cos_A);
  p_mR(cos_A,S10,P4,C6); 

/* ================================================================== */ 
  eigs_V_mR(cos_A,EigsVector); 
  transpose_mR(EigsVector,T_EigsVector);  
  
/* EigsValue : T_EigsVector * cos_A * EigsVector */
  mul_mR(T_EigsVector,cos_A,T1);
  mul_mR(T1,EigsVector,EigsValue);     
  
  printf(" acos(cos(A)) = A :");
  f_eigs_mR(acos,EigsValue,cos_EigsValue);  
     mul_mR(EigsVector,cos_EigsValue,T1);
     mul_mR(T1,T_EigsVector,A);  
       p_mR(A,S10,P4,C6);

  f_mR(A);
  f_mR(cos_A);

  f_mR(EigsVector);
  f_mR(T_EigsVector);
  
  f_mR(EigsValue);  
  f_mR(cos_EigsValue);    
      
  f_mR(T1);
}
/* ------------------------------------ */
int main(void)
{
time_t t;

  srand(time(&t));

do
{
  fun();

} while(stop_w());

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


Screen output example:

                                                                                       
 A :
   +1.2225    +0.0339    -0.4158    +0.1573    -0.0851 
   +0.0339    +0.5625    -0.1019    +0.0654    +0.2680 
   -0.4158    -0.1019    +0.6113    -0.3534    +0.3801 
   +0.1573    +0.0654    -0.3534    +0.3669    -0.3120 
   -0.0851    +0.2680    +0.3801    -0.3120    +0.7082 

 cos(A) :
   +0.3005    -0.0394    +0.3277    -0.1555    +0.1205 
   -0.0394    +0.8082    +0.0281    -0.0111    -0.1286 
   +0.3277    +0.0281    +0.6664    +0.2185    -0.2502 
   -0.1555    -0.0111    +0.2185    +0.8390    +0.1928 
   +0.1205    -0.1286    -0.2502    +0.1928    +0.6463 

 acos(cos(A)) = A :
   +1.2225    +0.0339    -0.4158    +0.1573    -0.0851 
   +0.0339    +0.5625    -0.1019    +0.0654    +0.2680 
   -0.4158    -0.1019    +0.6113    -0.3534    +0.3801 
   +0.1573    +0.0654    -0.3534    +0.3669    -0.3120 
   -0.0851    +0.2680    +0.3801    -0.3120    +0.7082 


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