Linear Algebra and the C Language/a0c5

Install and compile this file in your working directory.

/* ------------------------------------ */
/*  Save as :  c00b.c                   */
/* ------------------------------------ */
#include "v_a.h"
/* ------------------------------------ */
#define   RCA        RC5
/* ------------------------------------ */
/* ------------------------------------ */
double f(
double x)
{  
        return(cos(2*x));
}
char  feq[] =  "cos(2*x)";
/* ------------------------------------ */
double g(
double x)
{  
        return(2*cos(x)*cos(x)-1);
}
char  geq[] =  "2*cos(x)**2)-1";
/* ------------------------------------ */
/* ------------------------------------ */
void fun(void)
{
double **A             = rsymmetric_mR(i_mR(RCA,RCA),999.);
double **cos2_A       =                i_mR(RCA,RCA);
double **coscosmns1_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 **cos2A_EigsValue      =        i_mR(RCA,RCA);
double **coscosmns1_EigsValue =        i_mR(RCA,RCA);

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

  clrscrn();
  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(2*A)");
  f_eigs_mR(f,EigsValue,cos2A_EigsValue);
     mul_mR(EigsVector,cos2A_EigsValue,T1);
     mul_mR(T1,T_EigsVector,cos2_A);
       p_mR(cos2_A,S10,P4,C6); 

  printf(" 2*cos(A)**2-1");
  f_eigs_mR(g,EigsValue,coscosmns1_EigsValue); 
     mul_mR(EigsVector,coscosmns1_EigsValue,T1);
     mul_mR(T1,T_EigsVector,coscosmns1_A);
       p_mR(coscosmns1_A,S10,P4,C6); 
            
  f_mR(A);
  f_mR(cos2_A);
  f_mR(coscosmns1_A);
    
  f_mR(EigsVector);
  f_mR(T_EigsVector);
  
  f_mR(EigsValue);
  f_mR(coscosmns1_EigsValue);    
  f_mR(cos2A_EigsValue);    
      
  f_mR(T1);
}
/* ------------------------------------ */
int main(void)
{
time_t t;

  srand(time(&t));

do
{
  fun();

} while(stop_w());

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

Screen output example:

                                                                                       
 A :
 +450.0000  -668.0000  -561.0000   -14.0000  +411.0000 
 -668.0000  +631.0000  -449.0000  -944.0000  -989.0000 
 -561.0000  -449.0000  +939.0000   -26.0000  -474.0000 
  -14.0000  -944.0000   -26.0000  +844.0000  +794.0000 
 +411.0000  -989.0000  -474.0000  +794.0000  -311.0000 

 Press return to continue. 


 cos(2*A)
   -0.2251    +0.5058    -0.3585    +0.1855    -0.0735 
   +0.5058    -0.2351    +0.0086    +0.1749    +0.3666 
   -0.3585    +0.0086    +0.4637    +0.3454    +0.0597 
   +0.1855    +0.1749    +0.3454    -0.4969    -0.3568 
   -0.0735    +0.3666    +0.0597    -0.3568    +0.1306 

 2*cos(A)**2-1
   -0.2251    +0.5058    -0.3585    +0.1855    -0.0735 
   +0.5058    -0.2351    +0.0086    +0.1749    +0.3666 
   -0.3585    +0.0086    +0.4637    +0.3454    +0.0597 
   +0.1855    +0.1749    +0.3454    -0.4969    -0.3568 
   -0.0735    +0.3666    +0.0597    -0.3568    +0.1306 


 Press   return to continue
 Press X return to stop