pd.lib README.txt
2007-11-12 00:25content some simple modules and fucntions. The module is simple lazy sort implementation realised therewith heapq module. Two classes are provided by module: HeapSort On initialization accepted item list and comparing function; HeapSortByIndex On initialization accepted item list and index. List items mapped on index values and can be compared by them. HeapSortByIndexSafe It class liked on HeapSortByIndex above, but use index in extremely safe manner: if item omited from index it mapped on infinity and any item are comparable; Items Each item is a pair of object reference and object reference list which one depend; Best results achieved on litle values: the sort is for tree with a few cycles. The module contents **Lazy** decorator class used to cache return value on methods depend on argumetnts. some pro and contra of such programming are viewed from. ...
Short module description
Module pd.lib content some simple modules and fucntions.
Description of modules
pd.lib.heapsort
The module is simple lazy sort implementation realised therewith heapq module. Items will be sorted only when accepted and using of computation resource is minimazed.
Two classes are provided by module:
- HeapSort
- On initialization accepted item list and comparing function;
- HeapSortByIndex
- On initialization accepted item list and index. List items mapped on index values and can be compared by them. In this case third parameter - revert - are used. Revert can be True or False. If revert is True then array will be sorted in reverse order. Parameter revert is False by default.
- HeapSortByIndexSafe
- It class liked on HeapSortByIndex above, but use index in extremely safe manner: if item omited from index it mapped on infinity and any item are comparable;
Classes, mentioned above, to provide methods:
- chunk(n)
- Return first n items from begin sorted list.
pd.lib.utility
The module contents followed useful functions:
- name2klass
- Return klass by name
- klass2name
- Return name by klass
pd.lib.topsort
The module contents classes developed to provide different kind of topologic sort. All classes are use as:
TopSort([<Parameters>])(<Items>), где :
- Parameters
- Sort execution parameters;
- Items
- Each item is a pair of object reference and object reference list which one depend;
Followed classes are provided by module:
- TopSort
- Simple topologic sort;
- TopSortIndex
- Simple topologic sort for any kind of object;
- TopSortFuzzy
- Fuzzy topologic sort;
- TopSortFuzzyIndex
- Fuzzy topologic sort for any kind of object;
Fuzzy topologic sort can transform to linear ordered array graph with cyclomatic value more then zero. Best results achieved on litle values: the sort is for tree with a few cycles.
pd.lib.lazy
The module contents Lazy decorator class used to cache return value on methods depend on argumetnts. Be carryfully, method arguments are to be hashable.
Sample of use:
>>> from pd.lib.lazy import Lazy >>> >>> class A(object) : ... @Lazy ... def mul(self,a,b) : ... print a,b,"compute" ... return a*b ... >>> a=A() a.mul(1,2) 1 2 compute 2 >>> a.mul(2,3) 2 3 compute 6 >>> a.mul(1,2) 2 a.mul(2,3) 6 >>>
Using such version of lazy decorator get processes incredible speed, but more memory will be used.
pd.lib.fuzzyobject
The module provide FuzzyObject class. Inheritance from FuzzyObject to allow forget about typografic errors in class names:
>>> from pd.lib.fuzzyobject import FuzzyObject class A(FuzzyObject) : ... def commmon_function(self) : ... print 'common' ... def other_method(self) : ... print 'method' ... >>> A().coon_functi() common A().oth_m() method >>
This base class is toy, but it's worked. More complicated sample published in pd/lib/fuzzyobject/fuzzyobject_sample.py, some pro and contra of such programming are viewed from.
pd.lib.gcd
The module provide function gcd used to evaluate greatest common divisor:
>>> from pd.lib.gcd import gcd >>> gcd(10,15) 5
Conclusion
Main target of this product to carry all small, frequently used libraries. This library must be installed on use other our products by depend. But I think product have not got independent significance.


