Linear Algebra and the C Language/a0m1


Install and compile this file in your working directory.

/* ------------------------------------ */
/*  Save as :   c02b.c                  */
/* ------------------------------------ */
#include "v_a.h"
/* ------------------------------------ */
#define   RCA    RC4
/* ------------------------------------ */
#define    EV    R2  
/* ------------------------------------ */
int main(void)
{
double a[RCA*RCA]={
+5.701637292731, +0.991969965586, +0.254041088748, +1.125039107310, 
+0.991969965586, +6.402440296173, +0.359161539264, +1.590572531025, 
+0.254041088748, +0.359161539264, +5.091980394202, +0.407341745750, 
+1.125039107310, +1.590572531025, +0.407341745750, +6.803942016894    
};

double **A        =     ca_A_mR(a,                    i_mR(RCA,RCA));
double **EValue   =     eigs_mR(A,                    i_mR(RCA,RCA));

double **Ide      =      eye_mR(                      i_mR(RCA,RCA));
double **sIde     =     smul_mR(EValue[EV][C1],Ide,   i_mR(RCA,RCA));
double **AmnssIde =      sub_mR(A,sIde,               i_mR(RCA,RCA));

double **b        =       m0_mR(i_mR(RCA,C1));
double **Ab       = c_A_b_Ab_mR(AmnssIde,b, i_Abr_Ac_bc_mR(RCA,RCA,C1));

double **Ab_free  =                         i_Abr_Ac_bc_mR(RCA,RCA,RCA);
double **b_free   =                                   i_mR(RCA,RCA);

double **V        =                                   i_mR(RCA,RCA);

  clrscrn();
  printf(" The eigenvectors associated with eigenvalues\n"
         " with multiple multiplicity are not unique.  \n"
         " There exist several set of unit vectors that\n"
         " correspond to the same eigenspace.      \n\n\n"
         " A:");
  p_mR(A,S10,P5,C10);
          
                
        gj_PP_mR(Ab,YES);  
    put_zeroR_mR(Ab,Ab_free);
    put_freeV_mR(Ab_free); 
        gj_PP_mR(Ab_free,YES);      
       c_Ab_b_mR(Ab_free,b_free);

          c_c_mR(b_free,C2,V,EV); 
          c_c_mR(b_free,C3,V,EV+C1); 
          c_c_mR(b_free,C4,V,EV+C2); 
                    
    Normalize_mR(V);
           
           
          printf("\n\n\n"
                 " Copy V%d into the last file\n\n"
                 " V%d:",EV,EV);
          P_mR(V,S10,P12,C10); 
           
  stop();
             
  f_mR(A);
  f_mR(EValue);
  
  f_mR(Ide);
  f_mR(sIde);
  f_mR(AmnssIde);
  
  f_mR(Ab);
  f_mR(b);
  f_mR(Ab_free);    
  f_mR(b_free);
  
  f_mR(V); 
  
  return 0;
}
/* ------------------------------------ */
/* ------------------------------------ */

Screen output example:

                                                                                       
 The eigenvectors associated with eigenvalues
 with multiple multiplicity are not unique.  
 There exist several set of unit vectors that
 correspond to the same eigenspace.      


 A:
  +5.70164   +0.99197   +0.25404   +1.12504 
  +0.99197   +6.40244   +0.35916   +1.59057 
  +0.25404   +0.35916   +5.09198   +0.40734 
  +1.12504   +1.59057   +0.40734   +6.80394 




 Copy V2 into the last file

 V2:
      -nan, -0.816415639507, -0.340441083605, -0.848510478701, 
      -nan, +0.577464720627, +0.000000000000, +0.000000000000, 
      -nan, +0.000000000000, +0.940265849956, +0.000000000000, 
      -nan, +0.000000000000, +0.000000000000, +0.529178578114  

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