friendlysam.opt.Sum

class friendlysam.opt.Sum

A sum of items.

See the base class Operation for a basic description of attributes and methods.

Examples

Note that the constructor takes an iterable of arguments, just like the built-in sum() function, but the classmethod create() takes a list of arguments, as follows.

>>> x = VariableCollection('x')
>>> terms = [x(i) for i in range(4)]
>>> Sum(terms) == Sum.create(*terms)
True

>>> s = Sum(terms)
>>> s.evaluate(evaluators={Sum: sum})
Traceback (most recent call last):
...
TypeError: sum expected at most 2 arguments, got 4

>>> s.evaluate(evaluators={Sum: lambda *args: sum(args)})
<friendlysam.opt.Add at 0x...>

Sum.create(*args)	Classmethod to create a new Sum object.
Sum.evaluate([replace, evaluators])	Evaluate the expression recursively.

Sum.args	This property holds the arguments of the operation.
Sum.leaves	The leaves of the expression tree.
Sum.value	The concrete value of the expression, if possible.
Sum.variables	This property gives all leaves which are instances of Variable.