FACTOID # 37: American women have the most powerful jobs.
 
 Home   Encyclopedia   Statistics   Countries A-Z   Flags   Maps   Education   Forum   FAQ   About 
 
 
 
WHAT'S NEW
RECENT ARTICLES
More Recent Articles »
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Sparse grid

Sparse grids are a numerical technique to represent, integrate or interpolate high dimensional functions. They were originally found by the Russian mathematician Smolyak. Computer algorithms for efficient implementations of such grids were later developed by Michael Griebel and Christoph Zenger. 2-dimensional renderings (ie. ... Leonhard Euler is considered by many people to be one of the greatest mathematicians of all time A mathematician is a person whose primary area of study and research is mathematics. ...


Curse of dimension

The standard way of representing multidimensional functions are tensor or full grids. The number of basis functions or nodes (grid points) that have to be stored and processed depend exponentially on the number of dimensions. Even with today's computational power it is not possible to process functions with more than 4 or 5 dimensions. The exponential function is one of the most important functions in mathematics. ...


The curse of dimension is expressed in the order of the integration error that is made by a quadrature of level l, with Nl points. The function has regularity r, i.e. is r times differentiable. The number of dimensions is d.


|E_l| = O(N_l^{-frac{r}{d}})


Smolyak's quadrature rule

Smolyak found a computationally more efficient method of integrating multidimensional functions based on a univariate quadrature rule Q(1). The d-dimensional Smolyak integral Q(d)of a function f can be written as a recursion formula with the tensor product.


Q_l^{(d)} f = left(sum_{i=0}^l left(Q_i^{(1)}-Q_{i-1}^{(1)}right)otimes Q_{l-i}^{(d-1)}right)f


The index to Q is the level of the discretization. A 1-d integration on level i is computed by the evaluation of O(2i) points. The error estimate for a function of regularity r is:


|E_l| = Oleft(N_l^{-r}left(log N_lright)^{(d-1)(r+1)}right)


References

  • Finite difference scheme on sparse grids
  • Visualization on sparse grids
  • CiteSeer: Adaptive Sparse Grids, M. Hegland
  • Datamining on sparse grids J.Garcke, M.Griebel (pdf)

  Results from FactBites:
 
Scientific Visualization on Sparse Grids (729 words)
For interpolation on sparse grids, a hierarchy of basis functions is used, where some functions are defined on the entire grid.
The actual sparse grid is created by removing the points that do not contribute to the the sparse grid interpolation functions from the associated full grid (Figure 2).
Sparse grids need only a negligible amount of memory compared with their associated full grids as shown in Table 1.
NationMaster - Encyclopedia: Sparse grid (426 words)
Sparse grids are a numerical technique to represent, integrate or interpolate high dimensional functions.
For interpolation on sparse grids, a hierarchy of basis functions is used, where some functions are defined on the entire grid.
The actual sparse grid is created by removing the points that do not contribute to the the sparse grid interpolation functions from the associated full grid (Figure 2).
  More results at FactBites »


 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Lesson Plans | Student Area | Student FAQ | Reviews | Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 0825, e