GRID_DATASET
Generate Grid Datasets

GRID_DATASET is a FORTRAN90 program, using double precision arithmetic, which creates a grid dataset.

The program is interactive, and allows the user to choose

• M, the spatial dimension;
• N, the number of points to generate;
• SEED, the initial seed value;
• CENTER, the centering option;

Note that, unless N is an Mth power of an integer, the program must generate a regular grid with too many points, and then omit some. Choosing which points to omit is done with a random number generator, whose actions are controlled by SEED.

The actual placement of the grid within the unit hypercube leaves some options for the use. It is easiest to describe the options in the 1 dimensional case, and in terms of where the first and last grid point are. Assuming we have N evenly spaced points to place between 0 and 1, the centering options are

• CENTER = 1: first point is 0.0, last point is 1.0;
• CENTER = 2: first point is 1/(N+1), last point is N/(N+1);
• CENTER = 3: first point is 0, last point is (N-1)/N;
• CENTER = 4: first point is 1/N, last point is 1;
• CENTER = 5: first point is 1/(2*N), last point is (2*N-1)/(2*N);

Related Data and Programs:

GRID is a FORTRAN90 library of routines which can define a grid dataset. GRID_DATASET needs a compiled copy of that library in order to build the program.

GRID is a dataset directory which contains a number of sample grid datasets.

GRID_DATASET is also available in a C++ version and a MATLAB version.

TABLE is the format used for the output files created by GRID_DATASET

TABLE_DISCREPANCY is an executable C++ program which can read a TABLE file of points (presumed to lie in the unit hypercube) and compute bounds on the star discrepancy, a measure of dispersion.

Source Code:

• grid_dataset.f90, the source code.
• grid_dataset.csh, commands to compile and load the source code.

List of Routines:

• MAIN is the main program for GRID_DATASET.

You can go up one level to the FORTRAN90 source codes.