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#include "pv.h"
void leanconvert( float *S, float *C, int N2 , int amp, int ph)
{
#if 1
register int i;
float a = fabs(S[0]); /* real value at f=0 */
float b = fabs(S[1]); /* real value at f=Nyquist */
C[0] = a;
C[1] = 0;
S += 2,C += 2;
if(amp && ph) {
for ( i = 1; i < N2; i++,S += 2,C += 2 ) {
C[0] = hypot( S[0], S[1] );
C[1] = -atan2( S[1], S[0] );
}
}
else if(amp) {
for ( i = 1; i < N2; i++,S += 2,C += 2 )
C[0] = hypot( S[0], S[1] );
}
else if(ph) {
for ( i = 1; i < N2; i++,S += 2,C += 2 )
C[1] = -atan2( S[1], S[0] );
}
C[0] = b;
C[1] = 0;
#else
int real, imag,
amp, phase;
float a, b;
int i;
for ( i = 0; i <= N2; i++ ) {
imag = phase = ( real = amp = i<<1 ) + 1;
a = ( i == N2 ? S[1] : S[real] );
b = ( i == 0 || i == N2 ? 0. : S[imag] );
C[amp] = hypot( a, b );
C[phase] = -atan2( b, a );
}
#endif
}
/* unconvert essentially undoes what convert does, i.e., it
turns N2+1 PAIRS of amplitude and frequency values in
C into N2 PAIR of complex spectrum data (in rfft format)
in output array S; sampling rate R and interpolation factor
I are used to recompute phase values from frequencies */
void leanunconvert( float *C, float *S, int N2 )
{
#if 1
register int i;
S[0] = fabs(C[0]);
S[1] = fabs(C[N2*2]);
S += 2,C += 2;
for (i = 1; i < N2; i++,S += 2,C += 2 ) {
S[0] = C[0] * cos( C[1] );
S[1] = -C[0] * sin( C[1] );
}
#else
int real, imag,
amp, phase;
float a, b;
register int i;
for ( i = 0; i <= N2; i++ ) {
imag = phase = ( real = amp = i<<1 ) + 1;
S[real] = *(C+amp) * cos( *(C+phase) );
if ( i != N2 )
S[imag] = -*(C+amp) * sin( *(C+phase) );
}
#endif
}
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