numpy.polymul — NumPy v2.4.dev0 Manual (original) (raw)

numpy.polymul(a1, a2)[source]#

Find the product of two polynomials.

Note

This forms part of the old polynomial API. Since version 1.4, the new polynomial API defined in numpy.polynomial is preferred. A summary of the differences can be found in thetransition guide.

Finds the polynomial resulting from the multiplication of the two input polynomials. Each input must be either a poly1d object or a 1D sequence of polynomial coefficients, from highest to lowest degree.

Parameters:

a1, a2array_like or poly1d object

Input polynomials.

Returns:

outndarray or poly1d object

The polynomial resulting from the multiplication of the inputs. If either inputs is a poly1d object, then the output is also a poly1d object. Otherwise, it is a 1D array of polynomial coefficients from highest to lowest degree.

Examples

import numpy as np np.polymul([1, 2, 3], [9, 5, 1]) array([ 9, 23, 38, 17, 3])

Using poly1d objects:

p1 = np.poly1d([1, 2, 3]) p2 = np.poly1d([9, 5, 1]) print(p1) 2 1 x + 2 x + 3 print(p2) 2 9 x + 5 x + 1 print(np.polymul(p1, p2)) 4 3 2 9 x + 23 x + 38 x + 17 x + 3