`numpy.polynomial.chebyshev:chebmul`

source: build-install/usr/lib/python3.14/site-packages/numpy/polynomial/chebyshev.py :698

Signature

def chebmul ( c1 , c2 )

Summary

Multiply one Chebyshev series by another.

Extended Summary

Returns the product of two Chebyshev series c1 * c2. The arguments are sequences of coefficients, from lowest order "term" to highest, e.g., [1,2,3] represents the series T_0 + 2*T_1 + 3*T_2.

Parameters

c1, c2 : array_like: 1-D arrays of Chebyshev series coefficients ordered from low to high.

Returns

out : ndarray: Of Chebyshev series coefficients representing their product.

Notes

In general, the (polynomial) product of two C-series results in terms that are not in the Chebyshev polynomial basis set. Thus, to express the product as a C-series, it is typically necessary to "reproject" the product onto said basis set, which typically produces "unintuitive live" (but correct) results; see Examples section below.

Examples

from numpy.polynomial import chebyshev as C
c1 = (1,2,3)
c2 = (3,2,1)

✓

C.chebmul(c1,c2) # multiplication requires "reprojection"

✗

Aliases

numpy.polynomial.Chebyshev._mul
numpy.polynomial.chebyshev.chebmul