PRODUCT_RULE is a C++ program which creates a multidimensional quadrature rule by using a product of distinct one-dimensional quadrature rules.
The program reads a single input file, which contains a list that defines the 1D rules to be used as factors.
Each 1D rule is stored in three files, an "X", "W", and "R" file, which are assumed to share a common filename prefix, so that the files defined by a given prefix have the form:
For instance, let us suppose we want to compute a 2D product rule formed from a 3 point Clenshaw Curtis rule and a 2 point Gauss-Legendre rule. If the prefixes for these files were "cc_d1_o003" and "gl_d1_o002" respectively, then the input file to the program would read as follows:
cc_d1_o003 gl_d1_o002When the program read the first 1D rule, it would be searching for three files:
Once the program has computed the multidimensional product rule, it again writes out three files describing the product rule, with a common filename prefix specified by the user, which might be, for instance, product, in which case the files would be:
For information on the form of these files, see the QUADRATURE_RULES directory listed below.
product_rule ( list_file, product_prefix )where
If the arguments are not supplied on the command line, the program will prompt for them.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
PRODUCT_RULE is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version
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NINT_EXACTNESS_MIXED, a C++ program which measures the polynomial exactness of a multidimensional quadrature rule based on a mixture of 1D quadrature rule factors.
NINTLIB, a C++ library which numerically estimates integrals in multiple dimensions.
POWER_RULE, a C++ program which constructs a power rule, that is, a product quadrature rule from identical 1D factor rules.
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TEST_NINT, a C++ library which defines integrand functions for testing multidimensional quadrature routines.
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As an example, we make a 2D product rule.
The first factor is a 1D Clenshaw Curtis rule of order 3:
The second factor is a 1D Gauss Legendre rule of order 2:
We give the command
The resulting product rule files:
You can go up one level to the C++ source codes.