root_pol#

class diffsptk.PolynomialToRoots(order: int, *, eps: float | None = None, out_format: str | int = 'rectangular')[source]#

See this page for details.

Parameters:

orderint >= 1: The order of the polynomial.
epsfloat >= 0 or None: If the absolute values of the imaginary parts of the roots are all less than this value, they are considered as real roots.
out_format[‘rectangular’, ‘polar’]: The output format.

forward(a: Tensor) → Tensor[source]#

Find the roots of the input polynomial.

Parameters:

aTensor [shape=(…, M+1)]: The polynomial coefficients.

Returns:

outTensor [shape=(…, M)]: The roots.

Examples

>>> a = torch.tensor([3, 4, 5])
>>> root_pol = diffsptk.PolynomialToRoots(a.size(-1) - 1)
>>> x = root_pol(a)
>>> x
tensor([[-0.6667+1.1055j, -0.6667-1.1055j]])

diffsptk.functional.root_pol(a: Tensor, *, eps: float | None = None, out_format: str = 'rectangular') → Tensor[source]#

Compute roots of polynomial.

Parameters:

aTensor [shape=(…, M+1)]: The polynomial coefficients.
epsfloat >= 0 or None: If the absolute values of the imaginary parts of the roots are all less than this value, they are considered as real roots.
out_format[‘rectangular’, ‘polar’]: Output format.

Returns:

outTensor [shape=(…, M)]: The roots.