Example #1
0
  private static Dataset ifft1d(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);
        float[] fdata = null;
        shape = a.getShape();
        shape[axis] = n;
        result = new ComplexFloatDataset(shape);
        dest = new ComplexFloatDataset(new int[] {n});
        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.complexInverse(fdata, true);
          result.setItemsOnAxes(pos, hit, fdata);
        }
        break;
      case Dataset.FLOAT64:
      case Dataset.COMPLEX128:
        DoubleFFT_1D dfft = new DoubleFFT_1D(n);
        double[] ddata = null;
        shape = a.getShape();
        shape[axis] = n;
        result = new ComplexDoubleDataset(shape);
        dest = new ComplexDoubleDataset(new int[] {n});
        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.complexInverse(ddata, true);
          result.setItemsOnAxes(pos, hit, ddata);
        }
        break;
      default:
        logger.warn("Non-float dataset not yet supported");
        break;
    }

    return result;
  }
  public static void coupe100(AudioSignal input) {
    int fs = input.samplingRate;
    int N = input.getLength();
    float[] Y = Arrays.copyOf(input.data, 2 * N);
    FloatFFT_1D fft = new FloatFFT_1D(N);
    fft.realForwardFull(Y);

    int threshold = 100 * 2;
    Arrays.fill(Y, 0, Math.round(threshold * (float) N / fs), 0);
    Arrays.fill(Y, Math.round(2 * N - threshold * (float) N / fs), 2 * N - 1, 0);

    fft.complexInverse(Y, true);

    for (int i = 0; i < N; i++) {
      input.data[i] = Y[2 * i];
    }
  }