/* Composite sine-square bell. */

mid = size/8;

for( i = 0; i < mid; i++ )
   {
    w = sin( 0.5*PI*i/(mid - 1) )^2;

    rdata[i] *= w;
    idata[i] *= w;
   }

for( i = mid; i < size; i++ )
   {
    w *= sin( 0.5*PI + 0.5*PI*(i - mid)/(size - mid - 1) )^2;

    rdata[i] *= w;
    idata[i] *= w;
   }
