NAME
Math::Symbolic::Custom::Default - Default tree tests and transformations
SYNOPSIS
use Math::Symbolic;DESCRIPTION
This is a class of default tests and transformations for Math::Symbolic trees. For details on how the custom method delegation model works, please have a look at the Math::Symbolic::Custom and Math::Symbolic::Custom::Base classes.
EXPORT
Please see the docs for Math::Symbolic::Custom::Base for details, but you should not try to use the standard Exporter semantics with this class.
SUBROUTINES
is_integer()
is_integer() returns a boolean.
It returns true (1) if the tree is a constant object representing an integer value. It does not compute the value of the tree. (eg. '5*10' is not considered an integer, but '50' is.)
It returns false (0) otherwise.
is_constant()
is_constant() returns a boolean.
It returns true (1) if the tree consists of only constants and operators or if it becomes a tree of only constants and operators after application of derivatives.
It returns false (0) otherwise.
If you need not pay the price of applying derivatives, you should use the is_simple_constant() method instead.
is_simple_constant()
is_simple_constant() returns a boolean.
It returns true (1) if the tree consists of only constants and operators. As opposed to is_constant(), is_simple_constant() does not apply derivatives if necessary.
It returns false (0) otherwise.
is_sum()
(beta)
is_constant() returns a boolean.
It returns true (1) if the tree contains no variables (because it can then be evaluated to a single constant which is a sum). It also returns true if it is a sum or difference of constants and variables. Furthermore, it is true for products of integers and constants because those products are really sums of variables. If none of the above cases match, it applies all derivatives and tries again.
It returns false (0) otherwise.
Please contact the author in case you encounter bugs in the specs or implementation. The heuristics aren't all that great.
apply_derivatives()
Never modifies the tree in-place, but returns a modified copy of the original tree instead.
Applied to variables and constants, this method just clones.
Applied to operators and if the operator is a derivative, this applies the derivative to the derivative's first operand.
Regardless what kind of operator this is called on, apply_derivatives will be applied recursively on its operands.
If the first parameter to this function is an integer, at maximum that number of derivatives are applied (from top down the tree if possible).
apply_constant_fold()
Does not modify the tree in-place by default, but returns a modified copy of the original tree instead. If the first argument is true, the tree will not be cloned. If it is false or not existant, the tree will be cloned.
Applied to variables and constants, this method just clones.
Applied to operators, all tree segments that contain constants and operators only will be replaced with Constant objects.
AUTHOR
Steffen Mueller, <symbolic-module at steffen-mueller dot net>
New versions of this module can be found on http://steffen-mueller.net or CPAN.