void __ogg_fdcosqi(int n, float *wsave, int *ifac){
static float pih = 1.57079632679489661923132169163975;
static int k;
static float fk, dt;
dt=pih/n;
fk=0.;
for (k=0;k<n;k++){
fk+=1.;
wsave[k] = cos(fk*dt);
}
__ogg_fdrffti(n, wsave+n,ifac);
}
/**
* Prepares the arrays to be of length n.
*/
void FastFourierTransformer::reserve(int n)
{
Q_ASSERT(n>0);
if (m_waveFloat != 0) {
delete [] m_waveFloat;
}
if (m_workingArray != 0) {
delete [] m_workingArray;
}
if (m_ifac != 0) {
delete [] m_ifac;
}
m_workingArray = new float[2*n+15];
m_waveFloat = new float[n];
m_ifac = new int[n];
__ogg_fdrffti(n, m_workingArray, m_ifac);
m_last_n = n;
}
void
DiscreteFourierTransform(int n)
{
double p_value, upperBound, percentile, N_l, N_o, d, *m, *X, *wsave;
int i, count, ifac[15];
if ( ((X = (double*) calloc(n,sizeof(double))) == NULL) ||
((wsave = (double *)calloc(2*n,sizeof(double))) == NULL) ||
((m = (double*)calloc(n/2+1, sizeof(double))) == NULL) ) {
fprintf(stats[7],"\t\tUnable to allocate working arrays for the DFT.\n");
if( X == NULL )
free(X);
if( wsave == NULL )
free(wsave);
if( m == NULL )
free(m);
return;
}
for ( i=0; i<n; i++ )
X[i] = 2*(int)epsilon[i] - 1;
__ogg_fdrffti(n, wsave, ifac); /* INITIALIZE WORK ARRAYS */
__ogg_fdrfftf(n, X, wsave, ifac); /* APPLY FORWARD FFT */
m[0] = sqrt(X[0]*X[0]); /* COMPUTE MAGNITUDE */
for ( i=0; i<n/2; i++ )
m[i+1] = sqrt(pow(X[2*i+1],2)+pow(X[2*i+2],2));
count = 0; /* CONFIDENCE INTERVAL */
upperBound = sqrt(2.995732274*n);
for ( i=0; i<n/2; i++ )
if ( m[i] < upperBound )
count++;
percentile = (double)count/(n/2)*100;
N_l = (double) count; /* number of peaks less than h = sqrt(3*n) */
N_o = (double) 0.95*n/2.0;
d = (N_l - N_o)/sqrt(n/4.0*0.95*0.05);
p_value = erfc(fabs(d)/sqrt(2.0));
/*
printf("\t\t\t\tFFT TEST\n");
printf("\t\t-------------------------------------------\n");
printf("\t\tCOMPUTATIONAL INFORMATION:\n");
printf("\t\t-------------------------------------------\n");
printf("\t\t(a) Percentile = %f\n", percentile);
printf("\t\t(b) N_l = %f\n", N_l);
printf("\t\t(c) N_o = %f\n", N_o);
printf("\t\t(d) d = %f\n", d);
printf("\t\ttp_value = %f\n", p_value);
printf("\t\tstatus = %s\n", p_value < ALPHA ? "NON RANDOM" : "RANDOM");
printf("\t\t-------------------------------------------\n");
*/
fprintf(stats[TEST_FFT], "\t\t\t\tFFT TEST\n");
fprintf(stats[TEST_FFT], "\t\t-------------------------------------------\n");
fprintf(stats[TEST_FFT], "\t\tCOMPUTATIONAL INFORMATION:\n");
fprintf(stats[TEST_FFT], "\t\t-------------------------------------------\n");
fprintf(stats[TEST_FFT], "\t\t(a) Percentile = %f\n", percentile);
fprintf(stats[TEST_FFT], "\t\t(b) N_l = %f\n", N_l);
fprintf(stats[TEST_FFT], "\t\t(c) N_o = %f\n", N_o);
fprintf(stats[TEST_FFT], "\t\t(d) d = %f\n", d);
fprintf(stats[TEST_FFT], "\t\t-------------------------------------------\n");
fprintf(stats[TEST_FFT], "%s\t\tp_value = %f\n\n", p_value < ALPHA ? "FAILURE" : "SUCCESS", p_value);
fprintf(results[TEST_FFT], "%f\n", p_value);
free(X);
free(wsave);
free(m);
}
