SPARSE_GRID_CC
Sparse Grids
Clenshaw Curtis


SPARSE_GRID_CC is a dataset directory which contains examples of multidimensional sparse grid quadrature rules based on the one-dimensional Clenshaw Curtis rule.

A quadrature rule is a set of n points x and associated weights w so that the integral of a function f(x) over some particular region can be approximated by:

Integral f(x) dx = Sum ( 1 <= i <= n ) w(i) * f(x(i))

For this directory, a quadrature rule is stored as three files, containing the weights, the points, and a file containing two points defining the corners of the rectangular region. The dimension of the region is deduced implicitly from the dimension of the points.

Example:

Here are the three files associated with a sparse grid for two dimensions, based on the Clenshaw Curtis rule, for level 2 which has 13 points.

Here is the text of an "W" file storing the weights of such a rule


     -0.3555555555555558
     -0.0888888888888890
     -0.0888888888888890
     -0.0888888888888889
     -0.0888888888888889
      1.0666666666666667
      1.0666666666666669
      0.1111111111111111
      0.1111111111111111
      0.1111111111111111
      0.1111111111111111
      1.0666666666666667
      1.0666666666666669
      

Here is the text of a "X" file storing the abscissas of such a rule:


      0.0000000000000001      0.0000000000000001
     -1.0000000000000000      0.0000000000000001
      1.0000000000000000      0.0000000000000001
      0.0000000000000001     -1.0000000000000000
      0.0000000000000001      1.0000000000000000
     -0.7071067811865475      0.0000000000000001
      0.7071067811865476      0.0000000000000001
     -1.0000000000000000     -1.0000000000000000
     -1.0000000000000000      1.0000000000000000
      1.0000000000000000     -1.0000000000000000
      1.0000000000000000      1.0000000000000000
      0.0000000000000001     -0.7071067811865475
      0.0000000000000001      0.7071067811865476
      

Here is the text of an "R" file storing the lower and upper limits of the region, needed to determine the integration region:


    -1.0000000000000000        -1.0000000000000000    
     1.0000000000000000         1.0000000000000000  
      

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Related Data and Programs:

CLENSHAW_CURTIS_GRID is a FORTRAN90 library of routines which can compute Clenshaw Curtis grids.

NINT_EXACTNESS_MIXED is a C++ program which measures the polynomial exactness of a multidimensional quadrature rule based on a mixture of 1D quadrature rule factors.

SMOLPACK, a C library which estimates the integral of a function over a multidimensional hypercube using a sparse grid, by Knut Petras;

SPARSE_GRID_CC, a C++ library which creates sparse grids based on Clenshaw-Curtis rules.

SPARSE_GRID_CC_DATASET, a C++ program which creates a sparse grid dataset based on Clenshaw-Curtis rules.

SPARSE_GRID_DISPLAY, a MATLAB program which reads a file of points on a sparse grid, displays the grid and save the image in a PNG file;

SPARSE_GRID_MIXED, a C++ library which creates a sparse grid dataset based on a mixed set of 1D factor rules.

SPINTERP, a MATLAB library which carries out piecewise multilinear hierarchical sparse grid interpolation, by Andreas Klimke; ACM TOMS Algorithm 847.

TABLE, a data directory which contains examples of TABLE files, a simple format for N points in M dimensions;

Sample Files:

Some grids in 1D:

Clenshaw Curtis Sparse Quadrature Rules in 2D, defined on the [-1,1] square:

Clenshaw Curtis Sparse Quadrature Rules in 3D, defined on the [-1,1] cube:

Clenshaw Curtis Sparse Quadrature Rules in 4D, defined on the [-1,1] hypercube:

Clenshaw Curtis Sparse Quadrature Rules in 5D, defined on the [-1,1] hypercube:

Clenshaw Curtis Sparse Quadrature Rules in 6D, defined on the [-1,1] hypercube:

Clenshaw Curtis Sparse Quadrature Rules in 10D, defined on the [-1,1] hypercube:

Clenshaw Curtis Sparse Quadrature Rules in 100D, defined on the [-1,1] hypercube. Note that the volume of this hypercube is 2^100 or roughly 10^30!

You can go up one level to the DATASETS page.


Last revised on 23 January 2009.