diff options
Diffstat (limited to 'externals/grill/fftease/src/fft.c')
| -rw-r--r-- | externals/grill/fftease/src/fft.c | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/externals/grill/fftease/src/fft.c b/externals/grill/fftease/src/fft.c index 11c5da6d..4cd31199 100644 --- a/externals/grill/fftease/src/fft.c +++ b/externals/grill/fftease/src/fft.c @@ -1,8 +1,6 @@ #include "pv.h" -/* float TWOPI; */ - /* If forward is true, rfft replaces 2*N real data points in x with N complex values representing the positive frequency half of their Fourier spectrum, with x[1] replaced with the real part of the Nyquist @@ -12,6 +10,8 @@ static void bitreverse( float *x, int N ); +static float sqr(float x) { return x*x; } + void rfft( float *x, int N, int forward ) { float c1,c2, @@ -26,15 +26,12 @@ void rfft( float *x, int N, int forward ) i1,i2,i3,i4, N2p1; static int first = 1; -float PI, TWOPI; -PI = 3.141592653589793115997963468544185161590576171875; -TWOPI = 6.28318530717958623199592693708837032318115234375; - if ( first ) { + if ( first ) { first = 0; } - theta = PI/N; + theta = PV_PI/N; wr = 1.; wi = 0.; c1 = 0.5; @@ -50,7 +47,7 @@ TWOPI = 6.28318530717958623199592693708837032318115234375; xi = 0.; x[1] = 0.; } - wpr = -2.*pow( sin( 0.5*theta ), 2. ); + wpr = -2.*sqr( sin( 0.5*theta )); wpi = sin( theta ); N2p1 = (N<<1) + 1; for ( i = 0; i <= N>>1; i++ ) { @@ -104,14 +101,13 @@ void cfft( float *x, int NC, int forward ) m, i,j, delta; -float TWOPI; -TWOPI = 6.28318530717958623199592693708837032318115234375; - ND = NC<<1; + + ND = NC<<1; bitreverse( x, ND ); for ( mmax = 2; mmax < ND; mmax = delta ) { delta = mmax<<1; - theta = TWOPI/( forward? mmax : -mmax ); - wpr = -2.*pow( sin( 0.5*theta ), 2. ); + theta = PV_2PI/( forward? mmax : -mmax ); + wpr = -2.*sqr( sin( 0.5*theta )); wpi = sin( theta ); wr = 1.; wi = 0.; |