ikronf.c

java-fft-demo,用java开发的实现fft的平台

/*****************************************************/   
/*IkronF                                             */   
/*Maritza Rodr韌uez Mart韓ez                         */   
/*Computational Signal Processing Group - march-98   */   
/*CSPG - Dr. Domingo Rodr韌uez - Coordinator         */   
/*Description:		 			           */   
/*                                                   */   
/*This function ikronf performs the product between  */   
/*the tensor product of the matrices IR  and FS,     */   
/*where IR is the identity matrix of order R, and FS */   
/*is the Fourier matrix of order S. The parameter of */   
/*this function are R,and S.                         */   
/*****************************************************/   
   
   
COMPLEX **IkronF(int R,int S)   
{   
    
   COMPLEX **F;   
   COMPLEX **IkronF_VAR;   
   int temp,l=0,m,k,i,j;   
   F = getComplexMatrix(S);   
     
   IkronF_VAR = getComplexMatrix(R*S);    
    
      for(l = 0; l < S ; ++l){    
	     for(m = 0; m < S ; ++m)     
		    if(l==0 || m==0){     
		       F[l][m].real=1.0;     
		       F[l][m].imag=0.0;     
		       }      
		    else{     
		       F[l][m].real= cos((2*PI*l*m)/S);    
		       F[l][m].imag= -sin((2*PI*l*m)/S);    
		    }     
	  }     
	  l=0;      
         
      for(m = 0; m < (R*S); ++m) /* este es el valor de filas *columnas*/      
      {     
	     k=0;    
	     if (m % S ==0 & m!=0 ) /* el valor para comparar m debe ser el num de columnas de F*/    
	        l++;    
	     temp = R;     
     
      for (i = 0; i < temp; ++i)/* numero de filas o columnas mayor entre A y F*/      
      {     
	     for ( j = 0; j < S; ++j)/* numero de filas o columnas de F*/        
         {     
           if((l%R)==i){      
	         IkronF_VAR[m][k].real =  F[m % S][j].real; /* m%filas o columnas de F*/     
	         IkronF_VAR[m][k].imag = F[m % S][j].imag;      
	         k++;      
	       }     
	       else {     
	         IkronF_VAR[m][k].real = 0.0;    
	         IkronF_VAR[m][k].imag = 0.0;     
	         k++;      
      	   }      
         }       
      }       
      }      
   
   free(F);   
   return IkronF_VAR;     
}