private static Dataset fft1d(final Dataset a, final int n, final int axis) {
Dataset result = null;
Dataset dest = null;
int[] shape;
PositionIterator pi;
int[] pos;
boolean[] hit;
switch (a.getDtype()) {
case Dataset.FLOAT32:
case Dataset.COMPLEX64:
FloatFFT_1D ffft = new FloatFFT_1D(n);
shape = a.getShape();
shape[axis] = n;
result = new ComplexFloatDataset(shape);
dest = new ComplexFloatDataset(new int[] {2 * n});
float[] fdata = (float[]) dest.getBuffer();
pi = a.getPositionIterator(axis);
pos = pi.getPos();
hit = pi.getOmit();
while (pi.hasNext()) {
Arrays.fill(fdata, 0.f);
a.copyItemsFromAxes(pos, hit, dest);
ffft.complexForward(fdata);
result.setItemsOnAxes(pos, hit, fdata);
}
break;
case Dataset.FLOAT64:
case Dataset.COMPLEX128:
DoubleFFT_1D dfft = new DoubleFFT_1D(n);
shape = a.getShape();
shape[axis] = n;
result = new ComplexDoubleDataset(shape);
dest = new ComplexDoubleDataset(new int[] {2 * n});
double[] ddata = (double[]) dest.getBuffer();
pi = a.getPositionIterator(axis);
pos = pi.getPos();
hit = pi.getOmit();
while (pi.hasNext()) {
Arrays.fill(ddata, 0.);
a.copyItemsFromAxes(pos, hit, dest);
dfft.complexForward(ddata);
result.setItemsOnAxes(pos, hit, ddata);
}
break;
default:
logger.warn("Non-float dataset not yet supported");
break;
}
return result;
}
private void calculate() {
float[] samples = getSamples();
Window.apply(mWindow, samples);
if (mSampleType == SampleType.REAL) {
mFFT.realForward(samples);
} else {
mFFT.complexForward(samples);
}
dispatch(samples);
}