I actually manage to make it work ,when i insert into it a sin wave of a certain f.
This is the code :
COMPLEX_SPLIT A;
FFTSetup setupReal;
uint32_t log2n;
uint32_t n, nOver2;
int32_t stride;
uint32_t i;
float *originalReal, *obtainedReal;
float scale;
uint32_t L = 1024;
float *mag = new float[L/2];
log2n = 10 ;
n = 1 << log2n;
stride = 1;
nOver2 = n / 2;
//printf("1D real FFT of length log2 ( %d ) = %d\n\n", n, log2n);
A.realp = (float *) malloc(nOver2 * sizeof(float));
A.imagp = (float *) malloc(nOver2 * sizeof(float));
originalReal = (float *) malloc(n * sizeof(float));
obtainedReal = (float *) malloc(n * sizeof(float));
for (i = 0; i < n; i++)
originalReal[i] = cos(2*3.141592*11000*i/44100);//(float) (i + 1);
vDSP_ctoz((COMPLEX *) originalReal,2,&A,1,nOver2);
setupReal = vDSP_create_fftsetup(log2n, FFT_RADIX2);
vDSP_fft_zrip(setupReal, &A, stride, log2n, FFT_FORWARD);
//vDSP_fft_zrip(setupReal, &A, stride, log2n, FFT_INVERSE);
scale = (float) 1.0 / (2 * n);
vDSP_vsmul(A.realp, 1, &scale, A.realp, 1, nOver2);
vDSP_vsmul(A.imagp, 1, &scale, A.imagp, 1, nOver2);
//get magnitude;
for(i = 1; i < L/2; i++)
{
mag[i] = sqrtf(A.realp[i]*A.realp[i] + A.imagp[i] * A.imagp[i]);
NSLog(@"%d:%f",i,mag[i]);
}
Actually its not 44hz between bins,as the guy wrote in the post above! but 43 ! 22050/512=43 . this thing is critical ! because in the higher bins- such as bin[300] you get a completely different resault for 44 and 43 ! (its 300hz drift). so take care of that .