C C ________________________________________________________ C | | C | MULTIPLY A CIRCULANT MATRIX BY A VECTOR | C | | C | INPUT: | C | | C | X --VECTOR (COMPLEX ARRAY) | C | | C | A --EIGENVALUES COMPUTED BY OVALS | C | | C | N --MATRIX DIMENSION | C | | C | W --COMPLEX WORK ARRAY WITH AT LEAST N | C | ELEMENTS | C | | C | OUTPUT: | C | | C | Y --COMPLEX PRODUCT BETWEEN MATRIX AND X | C | | C | BUILTIN FUNCTIONS: CONJG | C | PACKAGE SUBROUTINES: FFT | C |________________________________________________________| C SUBROUTINE OMULT(Y,X,A,N,W) COMPLEX A(1),W(1),X(1),Y(1) REAL T T = N T = 1./T DO 10 I = 1,N 10 Y(I) = T*CONJG(X(I)) CALL FFT(Y,N,W) DO 20 I = 1,N 20 Y(I) = CONJG(Y(I))*A(I) CALL FFT(Y,N,W) RETURN END