DISK_GRID
Grid Points Within a Disk

DISK_GRID is a Python library which generates a grid of points over the interior of a disk in 2D.

The library allows the user to define an arbitrary disk by choosing its radius and center. The user also chooses N, the number of subintervals into which the horizontal radius line will be subdivided. It then returns the gridpoints defined by that choice.

Another function allows the user to specify that N points on a Fibonacci spiral are to be placed within the disk.

The test program creates input files to GNUPLOT which will create graphic images of the grids.

Licensing:

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

Languages:

DISK_GRID is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.

Related Data and Programs:

BALL_GRID, a Python library which computes a grid of points over the interior of a ball in 3D.

CIRCLE_ARC_GRID, a Python library which computes a grid of points along a circle or circular arc in 2D.

CUBE_GRID, a Python library which computes a grid of points over the interior of a cube in 3D.

DISK_INTEGRALS, a Python library which returns the exact value of the integral of any monomial over the interior of the unit disk in 2D.

DISK_RULE, a Python library which computes quadrature rules over the interior of the unit disk in 2D.

ELLIPSE_GRID, a Python library which computes a grid of points over the interior of an ellipse in 2D.

ELLIPSOID_GRID, a Python library which computes a grid of points over the interior of an ellipsoid in 3D.

HYPERCUBE_GRID, a Python library which computes a grid of points over the interior of a hypercube in M dimensions.

LINE_GRID, a Python library which computes a grid of points over the interior of a line segment in 1D.

POLYGON_GRID, a Python library which generates a grid of points over the interior of a polygon in 2D.

PYRAMID_GRID, a Python library which computes a grid of points over the interior of the unit pyramid in 3D;

SIMPLEX_GRID, a Python library which generates a regular grid of points over the interior of an arbitrary simplex in M dimensions.

SPHERE_FIBONACCI_GRID, a Python library which uses a Fibonacci spiral to create a grid of points on the surface of the unit sphere in 3D.

SPHERE_LLQ_GRID, a Python library which uses longitudes and latitudes to create grids of points, lines, and quadrilaterals on the surface of the unit sphere in 3D.

SPHERE_LLT_GRID, a Python library which uses longitudes and latitudes to create grids of points, lines, and triangles on the surface of the unit sphere in 3D.

SQUARE_GRID, a Python library which computes a grid of points over the interior of a square in 2D.

TETRAHEDRON_GRID, a Python library which computes a grid of points over the interior of a tetrahedron in 3D.

TRIANGLE_GRID, a Python library which computes a grid of points over the interior of a triangle in 2D.

WEDGE_GRID, a Python library which computes a grid of points over the interior of the unit wedge in 3D.

Reference:

1. Richard Swinbank, James Purser,
   Fibonacci grids: A novel approach to global modelling,
   Quarterly Journal of the Royal Meteorological Society,
   Volume 132, Number 619, July 2006 Part B, pages 1769-1793.

Source Code:

• disk_grid_regular.py, computes grid points inside a disk.
• disk_grid_regular_count.py, counts grid points inside a disk.
• disk_grid_display.py, displays grid points inside a disk.
• disk_grid_fibonacci.py, computes Fibonacci grid points inside a disk.
• r82vec_print_part.py, prints part of a vector of (X,Y) data.
• r8mat_transpose_write.py, writes the transpose of an R8MAT to a file.
• timestamp.py, prints the current YMDHMS date as a time stamp.

Examples and Tests:

• disk_grid_test.py, calls all the tests.
• disk_grid_test.sh, runs all the tests.
• disk_grid_test.txt, the output file.

The test for disk_grid_display creates a plot file:

• disk_grid_display.png, an image of the points.

The test for disk_grid_fibonacci creates a data file and a plot file:

• disk_grid_fibonacci.xy, the coordinates of the Fibonacci grid points.
• disk_grid_fibonacci.png, an image of the Fibonacci grid points.

The test for disk_grid_regular creates a data file and a plot file:

• disk_grid_regular.xy, the coordinates of the grid points.
• disk_grid_regular.png, an image of the points.

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