fkroni.c

java-fft-demo,用java开发的实现fft的平台

/*****************************************************/   
/*FkronI					                 */   
/*Maritza Rodr韌uez Mart韓ez			           */   
/*Computational Signal Processing Group - march-98   */   
/*CSPG - Dr. Domingo Rodr韌uez - Coordinator         */   
/*						                 */   
/*Description:					           */   
/*This function fkroni performs the product between  */   
/*the tensor product of matrices  FR and IS, where FR*/   
/*is the Fourier matrix of order R,  and IS is the   */   
/*identity matix of order S.  			     */   
/*****************************************************/   
   
COMPLEX **FkronI(int R,int S)   
{   

  COMPLEX **A;
  COMPLEX **B;
  COMPLEX **FkronI_VAR;
  int temp,l=0,m,k,i,j;

  A = getComplexMatrix(R);
  B = getComplexMatrix(S);

  FkronI_VAR = getComplexMatrix(R*S);

					/* crea la matriz Is */   
	for(l=0; l <S ; ++l)  
	   for(m=0; m <S ; ++m)  
		if(m==l){   
		   B[l][m].real=1.0;   
		   B[l][m].imag=0.0;   
		   }   
		else{   
		   B[l][m].real =0;   
		   B[l][m].imag=0;   
		   }   
					/* crea la matriz Fr*/   
	for(l=0; l < R ; ++l)   
	   for(m=0; m < R ; ++m)   
		if(l==0 || m==0){   
		   A[l][m].real=1.0;   
		   A[l][m].imag=0.0;   
		}   
		else{   
		A[l][m].real=cos((-2*PI*l*m)/R);   
		A[l][m].imag=-sin((-2*PI*l*m)/R);   
		}   
   
  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 B*/   
	l++;   
   

temp =R;   

   for ( i=0; i < temp; ++i)/* numero de filas o columnas mayor entre A y B*/   
   {   
	for ( j=0; j < S; ++j)/* numero de filas o columnas de B*/   
	{   
   
	   FkronI_VAR[m][k].real = A[l%R][i].real * B[m % S][j].real; /* m%filas o columnas de B*/   
	   FkronI_VAR[m][k].imag = A[l%R][i].imag * B[m % S][j].imag; /* m%filas o columnas de B*/   
	   k++;   
	}   
    
   }   
 }   
 free(A);   
 free(B);   
    return FkronI_VAR;    
    
}