numpy.polyval — NumPy v2.2 Manual (original) (raw)

numpy.polyval(p, x)[source]#

Evaluate a polynomial at specific values.

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.

If p is of length N, this function returns the value:

p[0]x(N-1) + p[1]x(N-2) + ... + p[N-2]*x + p[N-1]

If x is a sequence, then p(x) is returned for each element of x. If x is another polynomial then the composite polynomial p(x(t))is returned.

Parameters:

parray_like or poly1d object

1D array of polynomial coefficients (including coefficients equal to zero) from highest degree to the constant term, or an instance of poly1d.

xarray_like or poly1d object

A number, an array of numbers, or an instance of poly1d, at which to evaluate p.

Returns:

valuesndarray or poly1d

If x is a poly1d instance, the result is the composition of the two polynomials, i.e., x is “substituted” in p and the simplified result is returned. In addition, the type of x - array_like or poly1d - governs the type of the output: x array_like => _values_array_like, x a poly1d object => values is also.