freqt¶

class diffsptk.FrequencyTransform(in_order, out_order, alpha)[source]¶

See this page for details.

Parameters

in_orderint >= 0 [scalar]: Order of input sequence, \(M_1\).
out_orderint >= 0 [scalar]: Order of output sequence, \(M_2\).
alphafloat [-1 < alpha < 1]: Frequency warping factor, \(\alpha\).

forward(x)[source]¶

Perform frequency transform.

Parameters

xTensor [shape=(…, M1+1)]: Input sequence.

Returns

yTensor [shape=(…, M2+1)]: Warped sequence.

Examples

>>> x = diffsptk.ramp(3)
tensor([0., 1., 2., 3.])
>>> freqt = diffsptk.FrequencyTransform(3, 4, 0.02)
>>> y = freqt(x)
>>> y
tensor([ 0.0208,  1.0832,  2.1566,  2.9097, -0.1772])
>>> freqt2 = diffsptk.FrequencyTransform(4, 3, -0.02)
>>> x2 = freqt2(y)
>>> x2
tensor([-9.8953e-10,  1.0000e+00,  2.0000e+00,  3.0000e+00])