sym package

unified wrapper to symbolic manipulation libraries in Python

Submodules

sym.backend module

sym.backend.Backend(name=None, envvar='SYM_BACKEND', default='sympy')

Backend for the underlying symbolic manipulation pacages

Parameters:

name: str (default: None)

Name of package e.g. ‘sympy’

envvar: str (default: ‘SYM_BACKEND’)

name of environmentvariable to read name from (when name is None)

default: str

name to use when the environment variable described by envvar is unset or empty (default: ‘sympy’)

Examples

>>> be = Backend('sympy')  # or e.g. 'symengine'
>>> x, y = map(be.Symbol, 'xy')
>>> exprs = [x + y + 1, x*y**2]
>>> lmb = be.Lambdify([x, y], exprs)
>>> import numpy as np
>>> lmb(np.arange(6.0).reshape((3, 2)))
array([[   2.,    0.],
       [   6.,   18.],
       [  10.,  100.]])

sym.util module

sym.util.banded_jacobian(y, x, ml, mu)

Calculates a banded version of the jacobian

Compatible with the format requested by scipy.integrate.ode() (for SciPy >= v0.15).

Parameters:

y: array_like of expressions

x: array_like of symbols

ml: int

number of lower bands

mu: int

number of upper bands

Returns:

2D array of shape (1+ml+mu, len(y))