Wiki » History » Version 9
Version 8 (M. Rolf, 09/21/2011 04:18 PM) → Version 9/12 (M. Rolf, 09/29/2011 01:45 PM)
SVN: https://code.cor-lab.org/svn/nemomath/
h1. Wiki
* [[Installation]]
h2. Why NemoMath?
NemoMath is a math-library for robotics and learning... *so why don't you just use Eigen 2???*
The answer is twofold:
h3. 1.: NemoMath takes care of shared ownership issues in robotics/learning _applications and systems_.
Use Eigen (or similar Libs) in something more complex than one method of spaghetti code and you need to think about two questions:
* Who is responsible for *deleting* an object?
* Who is allowed to *modify* an object (mutability) and when is a *copy* necessary?
The first thing that people usually come up with are smart-pointers like @boost::shared_ptr@. It solves the problem when to delete an object. But, it makes the mutability-issue even worse, since it is not transparent to const-correctness. There is always a danger that some other objects holds a smart pointer on your vector and modifies it. Also, you lose a lot of the original API convenience, such as mathematical operators, which are not directly usable through a smart-pointer.
NemoMath tackles these problem elegantly in the background by using
* Highly efficient *intrusive-counters* on internal data-objects. Passing a @nemo::MathVector@ is almost as efficient as passing a plain C-pointer.
* *Copy-on-write* on all Vector and Matrix objects. You can pass them without expensive copying been performed. Once a write-operation takes place, the library takes care of a copy.
Due to these two features, working with @nemo::MathVector@ and @nemo::Matrix@ feels like using simple objects, with which you can do "value-based" programming.
Yet it avoids all the typical overhead. See source:/trunk/nemomath/examples/ExampleVector.cpp
h3. 2.: NemoMath goes _far beyond linear algebra_.
Ultra-flexible Functor API
* Define your own Mappings and combine them flexibly: source:/trunk/nemomath/examples/ExampleMapping.cpp
* Or just use the operators to express things simply and elegantly: (see source:/trunk/nemomath/examples/ExampleMappingArithmetics.cpp )
Convenient container data-structures
* Allows flexible interaction with functor objects: source:/trunk/nemomath/examples/ExampleCollections.cpp
* These data-structures will be STL-compliant in (in the next version of NemoMath versions STL-compliant) container data-structures.
h1. Wiki
* [[Installation]]
h2. Why NemoMath?
NemoMath is a math-library for robotics and learning... *so why don't you just use Eigen 2???*
The answer is twofold:
h3. 1.: NemoMath takes care of shared ownership issues in robotics/learning _applications and systems_.
Use Eigen (or similar Libs) in something more complex than one method of spaghetti code and you need to think about two questions:
* Who is responsible for *deleting* an object?
* Who is allowed to *modify* an object (mutability) and when is a *copy* necessary?
The first thing that people usually come up with are smart-pointers like @boost::shared_ptr@. It solves the problem when to delete an object. But, it makes the mutability-issue even worse, since it is not transparent to const-correctness. There is always a danger that some other objects holds a smart pointer on your vector and modifies it. Also, you lose a lot of the original API convenience, such as mathematical operators, which are not directly usable through a smart-pointer.
NemoMath tackles these problem elegantly in the background by using
* Highly efficient *intrusive-counters* on internal data-objects. Passing a @nemo::MathVector@ is almost as efficient as passing a plain C-pointer.
* *Copy-on-write* on all Vector and Matrix objects. You can pass them without expensive copying been performed. Once a write-operation takes place, the library takes care of a copy.
Due to these two features, working with @nemo::MathVector@ and @nemo::Matrix@ feels like using simple objects, with which you can do "value-based" programming.
Yet it avoids all the typical overhead. See source:/trunk/nemomath/examples/ExampleVector.cpp
h3. 2.: NemoMath goes _far beyond linear algebra_.
Ultra-flexible Functor API
* Define your own Mappings and combine them flexibly: source:/trunk/nemomath/examples/ExampleMapping.cpp
* Or just use the operators to express things simply and elegantly: (see source:/trunk/nemomath/examples/ExampleMappingArithmetics.cpp )
Convenient container data-structures
* Allows flexible interaction with functor objects: source:/trunk/nemomath/examples/ExampleCollections.cpp
* These data-structures will be STL-compliant in (in the next version of NemoMath versions STL-compliant) container data-structures.