HYPERCUBE_EXACTNESS is a C program which investigates the polynomial exactness of a quadrature rule over the interior of the hypercube in M dimensions.
The polynomial exactness of a quadrature rule is defined as the highest total degree D such that the quadrature rule is guaranteed to integrate exactly all polynomials of total degree DEGREE_MAX or less, ignoring roundoff. The total degree of a polynomial is the maximum of the degrees of all its monomial terms. The degree of a monomial term is the sum of the exponents. Thus, for instance, the DEGREE of
x^{2}y z^{5}is 2+1+5=8.
To be thorough, the program starts at DEGREE = 0, and then proceeds to DEGREE = 1, 2, and so on up to a maximum degree DEGREE_MAX specified by the user. At each value of DEGREE, the program generates every possible monomial term, applies the quadrature rule to it, and determines the quadrature error. The program uses a scaling factor on each monomial so that the exact integral should always be 1; therefore, each reported error can be compared on a fixed scale.
The program is very flexible and interactive. The quadrature rule is defined by three files, to be read at input, and the maximum degree is specified by the user as well.
Note that the three files that define the quadrature rule are assumed to have related names, of the form
The exactness results are written to an output file with the corresponding name:
HYPERCUBE_EXACTNESS prefix degree_maxwhere
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.
HYPERCUBE_EXACTNESS is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version.
CUBE_EXACTNESS, a C library which investigates the polynomial exactness of quadrature rules over the interior of a cube in 3D.
EXACTNESS, a C library which investigates the exactness of quadrature rules that estimate the integral of a function with a density, such as 1, exp(-x) or exp(-x^2), over an interval such as [-1,+1], [0,+oo) or (-oo,+oo).
HYPERCUBE_GRID, a C library which computes a grid of points over the interior of a hypercube in M dimensions.
PYRAMID_EXACTNESS, a C program which investigates the polynomial exactness of a quadrature rule over the interior of the unit pyramid in 3D.
SPHERE_EXACTNESS, a C program which tests the monomial exactness of a quadrature rule on the surface of the unit sphere in 3D.
SQUARE_EXACTNESS, a C library which investigates the polynomial exactness of quadrature rules for f(x,y) over the interior of a rectangle in 2D.
TETRAHEDRON_EXACTNESS, a C program which investigates the polynomial exactness of a quadrature rule over the interior of a tetrahedron in 3D.
TRIANGLE_EXACTNESS, a C program which investigates the polynomial exactness of a quadrature rule over the interior of a triangle in 2D.
WEDGE_EXACTNESS, a C program which investigates the monomial exactness of a quadrature rule over the interior of the unit wedge in 3D.
CC_D1_O2 is a Clenshaw-Curtis order 2 rule for 1D.
CC_D1_O3 is a Clenshaw-Curtis order 3 rule for 1D. If you are paying attention, you may be surprised to see that a Clenshaw Curtis rule of odd order has one more degree of accuracy than you'd expect!
CC_D2_O3x3 is a Clenshaw-Curtis 3x3 product rule for 2D.
CC_D3_O3x3x3 is a Clenshaw-Curtis 3x3x3 product rule for 3D.
CCGL_D2_O3x2 is a product rule for 2D whose factors are a Clenshaw-Curtis of order 3 and a Gauss-Legendre rule of order 2.
CC_D2_LEVEL0 is a Clenshaw Curtis sparse rule for 2D of level 0 and order 1.
CC_D2_LEVEL1 is a Clenshaw Curtis sparse rule for 2D of level 1 and order 5.
CC_D2_LEVEL2 is a Clenshaw Curtis sparse rule for 2D of level 2 and order 13.
CC_D2_LEVEL3 is a Clenshaw Curtis sparse rule for 2D of level 3 and order 25.
CC_D2_LEVEL4 is a Clenshaw Curtis sparse grid rule for 2D of level 4 and order 65.
CCS_D2_LEVEL4 is a Clenshaw Curtis "Slow-Exponential-Growth" sparse grid rule for 2D of level 4 and order 49.
GL_D1_O3 is a Gauss-Legendre order 3 rule for 1D.
GL_D2_O3x3 is a Gauss-Legendre 3x3 product rule for 2D.
GL_D3_O3x3x3 is a Gauss-Legendre 3x3x3 product rule for 3D.
NCC_D1_O5 is a Newton-Cotes Closed order 5 rule for 1D.
NCC_D2_O5x5 is a Newton-Cotes Closed 5x5 product rule for 2D.
NCC_D3_O125 is a Newton-Cotes Closed 5x5x5 product rule for 3D.
You can go up one level to the C source codes.