Goulib.expr module

simple symbolic math expressions

Goulib.expr.add_function(f, s=None, r=None, l=None)

add a function to those allowed in Expr.

Parameters:

• f – function
• s – string representation, should be formula-like
• r – repr representation, should be cut&pastable in a calculator, or in python ...
• l – LaTeX representation

Goulib.expr.add_module(module)

Goulib.expr.eval(node, ctx={})

safe eval of ast node : only _functions and _operators listed above can be used

Parameters:

• node – ast.AST to evaluate
• ctx – dict of varname : value to substitute in node

Returns:

number or expression string

Goulib.expr.get_function_source(f)

returns cleaned code of a function or lambda currently only supports: - lambda x:formula_of_(x) - def anything(x): return formula_of_(x)

Goulib.expr.plouffe(f, epsilon=1e-06)

class Goulib.expr.Expr(f)

Bases: Goulib.plot.Plot

Math expressions that can be evaluated like standard functions combined using standard operators and plotted in IPython/Jupyter notebooks

Parameters:f – function or operator, Expr to copy construct, or formula string

__init__(f)

Parameters:f – function or operator, Expr to copy construct, or formula string

isNum

isconstant

Returns:True if Expr evaluates to a constant number or bool

__call__(x=None, **kwargs)

evaluate the Expr at x OR compose self(x())

__float__()

__repr__()

__str__()

latex()

Returns:string LaTex formula

apply(f, right=None)

function composition self o f = f(self(x))

applx(f, var='x')

function composition f o self = self(f(x))

__eq__(other)

__ne__(other)

__lt__(other)

__le__(other)

__ge__(other)

__gt__(other)

__add__(right)

__sub__(right)

__neg__()

__mul__(right)

__rmul__(right)

__truediv__(right)

__pow__(right)

__div__(right)

__invert__()

__and__(right)

__or__(right)

__xor__(right)

__lshift__(dx)

__rshift__(dx)

complexity()

measures the complexity of Expr :return: int, sum of the precedence of used ops

__class__

alias of type

__delattr__

Implement delattr(self, name).

__dir__() → list

default dir() implementation

__format__()

default object formatter

__getattribute__

Return getattr(self, name).

__hash__ = None

__new__()

Create and return a new object. See help(type) for accurate signature.

__reduce__()

helper for pickle

__reduce_ex__()

helper for pickle

__setattr__

Implement setattr(self, name, value).

__sizeof__() → int

size of object in memory, in bytes

html(**kwargs)

plot(**kwargs)

renders on IPython Notebook (alias to make usage more straightforward)

png(**kwargs)

render(fmt='svg', **kwargs)

save(filename, **kwargs)

svg(**kwargs)

class Goulib.expr.TextVisitor(dialect)

Bases: ast.NodeVisitor

Parameters:dialect – int index in _operators of symbols to use

__init__(dialect)

Parameters:dialect – int index in _operators of symbols to use

prec(op)

calculate the precedence of op

__class__

alias of type

__delattr__

Implement delattr(self, name).

__dir__() → list

default dir() implementation

__eq__

Return self==value.

__format__()

default object formatter

__ge__

Return self>=value.

__getattribute__

Return getattr(self, name).

__gt__

Return self>value.

__hash__

Return hash(self).

__le__

Return self<=value.

__lt__

Return self<value.

__ne__

Return self!=value.

__new__()

Create and return a new object. See help(type) for accurate signature.

__reduce__()

helper for pickle

__reduce_ex__()

helper for pickle

__repr__

Return repr(self).

__setattr__

Implement setattr(self, name, value).

__sizeof__() → int

size of object in memory, in bytes

__str__

Return str(self).

visit(node)

Visit a node.

visit_Call(n)

visit_Name(n)

visit_NameConstant(node)

visit_UnaryOp(n)

visit_BinOp(n)

visit_Compare(n)

visit_Num(n)

generic_visit(n)