eval_chebyshev: Evaluate a Chebyshev series on a ciphertext

In openfhe.R: R Interface to the 'OpenFHE' Fully Homomorphic Encryption Library

Evaluate a Chebyshev series on a ciphertext

Description

Uses OpenFHE's default algorithm selector, which routes to eval_chebyshev_linear() for degree < 5 and eval_chebyshev_ps() (Paterson-Stockmeyer) for higher degrees. Call the variants directly to force one algorithm or the other.

Usage

eval_chebyshev(ct, coefficients, a, b)

Arguments

ct	A Ciphertext
coefficients	Integer, double or complex vector of Chebyshev coefficients. Each type is evaluated with its own arithmetic, as for eval_poly(). Pass whole-number coefficients as doubles (c(1, 2, 3), not c(1L, 2L, 3L)): at OpenFHE 1.6.1 the Paterson-Stockmeyer evaluator, which this function uses from degree 5, returns wrong values for integer coefficients.
a	Lower bound of the approximation interval
b	Upper bound of the approximation interval

Value

A Ciphertext

See Also

eval_chebyshev_coefficients() and eval_chebyshev_function() for constructing the coefficient vector from a user-supplied function; eval_chebyshev_linear() / eval_chebyshev_ps() for forcing the algorithm.

openfhe.R documentation built on Nov. 13, 2026, 5:07 p.m.