poly_eval

Fast polynomial evaluation powered by Cython and NumPy.

Features

• Polynomial — real-valued coefficients and exponents
• StrictPolynomial — exponents constrained to non-negative integers
• Real evaluation — evaluate_real(inp, mag_only=False)
• Complex evaluation — evaluate_complex(real, imag, mag_only=False)
• Real→complex — evaluate_real_to_complex(inp, mag_only=False)
• Magnitude-only mode — applies exponent to |x| while preserving sign/direction
• Addition — O(n+m) merge of sorted exponent arrays
• Multiplication — convolution via dict merge
• Cython nogil kernels for all evaluation paths

Installation

pip install numpy Cython
python setup.py install

Quickstart

import numpy as np
from pyevalpoly import Polynomial

p = Polynomial([(1.0, 2.0), (2.0, 1.0), (0.5, 0.0)])
# 0.5 + 2x + x²

x = np.array([1.0, 2.0, 3.0])
print(p.evaluate_real(x))
# [3.5  8.5 15.5]

# Magnitude-only (|x|^e * sign(x))
print(p.evaluate_real(x, mag_only=True))

# Complex evaluation
re = np.array([1.0, -1.0])
im = np.array([2.0, -2.0])
out = p.evaluate_complex(re, im)  # shape (2, 2)

# Arithmetic
q = Polynomial([(3.0, 1.0), (1.0, 0.0)])
r = p + q  # terms with matching exponents are summed
s = p * q  # convolution

Classes

Polynomial(terms)          — terms: list of (coeff, exp) or PolyComponent
StrictPolynomial(terms)   — same, but exponents must be non-negative integers
PolyComponent(coeff, exp)  — named tuple for term construction
StrictPolyComponent(...)   — named tuple for strict construction

Evaluation methods

Each method preserves the input shape on the real axis and appends a final dimension of size 2 for complex outputs.

All methods accept the keyword argument mag_only=False. When True, each term c·x^e is evaluated as c·sgn(x)·|x|^e, keeping the direction but applying the exponent only to the magnitude.

License

MIT