/* Converts the FFTed data in the complex conjugate */ static VALUE dvector_fft_conj(VALUE self) { long len; double * v1 = Dvector_Data_for_Write(self, &len); double * img; long i; for(i = 1, img = v1 + len-1; i < (len+1)/2; i++, img--) *img = -*img; return self; }