kwant.continuum.lambdify

kwant.continuum.lambdify(expr, locals=None)

Return a callable object for computing a continuum Hamiltonian.

Warning

This function uses eval (because it calls sympy.sympify), and thus should not be used on unsanitized input.

If necessary, the given expression is sympified using kwant.continuum.sympify. It is then converted into a callable object.

Parameters:

• expr (str or SymPy expression) – Expression to be converted into a callable object

• locals (dict or None (default)) – Additional definitions for sympify.

Examples

>>> f = lambdify('a + b', locals={'b': 'b + c'})
>>> f(1, 3, 5)
9

>>> ns = {'sigma_plus': [[0, 2], [0, 0]]}
>>> f = lambdify('k_x**2 * sigma_plus', ns)
>>> f(0.25)
array([[ 0.   ,  0.125],
       [ 0.   ,  0.   ]])