seemps.analysis.chebyshev.cheb2mpo

seemps.analysis.chebyshev.cheb2mpo(coefficients, initial_mpo, strategy=<seemps.state.core.Strategy object>, clenshaw=True, rescale=True)

Composes a function on an initial MPO by expanding it on the basis of Chebyshev polynomials.

Parameters:

coefficientsnp.polynomial.Chebyshev

The Chebyshev expansion coefficients representing the target function that is defined on a given interval [a, b].

initial_mpoMPO

The initial MPO on which to apply the expansion. By default (if rescale is True), it must have a support inside the domain of definition of the function [a, b]. If rescale is False, it must have a support inside [-1, 1].

strategyStrategy, default=DEFAULT_STRATEGY

The simplification strategy for operations between MPS.

clenshawbool, default=True

Whether to use the Clenshaw algorithm for polynomial evaluation.

rescalebool, default=True

Whether to perform an affine transformation of the initial MPO from the domain [a, b] of the Chebyshev coefficients to the canonical Chebyshev interval [-1, 1].

Returns:

f_mpoMPO

MPO representation of the polynomial expansion.