Affine Pattern Matching¶
- affine_inputs(fn)[source]¶
Returns a [sound sub]set of real inputs of
fn
wrt whichfn
is known to be affine.
- extract_affine(fn)[source]¶
Extracts an affine representation of a funsor, satisfying:
x = ... const, coeffs = extract_affine(x) y = sum(Einsum(eqn, coeff, Variable(var, coeff.output)) for var, (coeff, eqn) in coeffs.items()) assert_close(y, x) assert frozenset(coeffs) == affine_inputs(x)
The
coeffs
will have one key per input wrt whichfn
is known to be affine (viaaffine_inputs()
), andconst
andcoeffs.values
will all be constant wrt these inputs.The affine approximation is computed by ev evaluating
fn
at zero and each basis vector. To improve performance, users may want to run under theMemoize()
interpretation.