INTRODUCTION

This module provides access through Python to the collection of Fortran programs in
REGRIDPACK, which is a collection of programs produced at the National Center for
Atmospheric Research by John C. Adams for linear or cubic interpolation in one, two,
three or four dimensions.

RESTRICTIONS

This module provides regridding by interpolation only. In other words, the output coordinate
vector can not extend beyond the limits of the input coordinate vector.

Each coordinate vector must be monotonically increasing or decreasing.

Missing data is not allowed in the input data.


CAPABLITIES

This module allows linear or cubic interpolation in one, two, three or four dimensions. The
computation can use the grid vectors assocated with the input and the output data or just
thier sizes if the input and output vectors are uniformly spaced. However, the selection of
of the uniform option must apply to all the dimensions in the requested interpolation. In
addition, the computation in the nonuniform case can use the log of the grid vectors choosen
dimension by dimension. It is possible to regrid a subset of the dimensions in the input data.
A utility function is provide to generate a gaussian or a uniform grids to use as a output
coordinate vector.


ORGANIZATION

This module is object oriented for simplicity. It is organized as a single class called Regrid,
which begins with a capital letter. Python is case sensitive. It contains the single function,
rgrd, which performs the computation in one, two, three or four dimensions.

Access to the function rgrd is provided through a simple two step process. The first step is making
an instance of the class passing the coordinate vectors and associated information. The second step
is calling the regridding function with the data in the argument list and an optional missing data value
to request a check for the presence of a missing data.

HELP

To obtain a prescription for making an instance, type

adamsregrid.help('Regrid')

To acquire instructions on the use of the rgrd function, type

adamsregrid.help('rgrd')

To look at a general one dimensional example, type

adamsregrid.help('OneDexample')

To look at a general four dimensional example, type

adamsregrid.help('FourDexample')

DOCUMENTATION

Documentation written to the file regridmodule.doc can be produced after importing the adamsregrid module
by typing

adamsregrid.document()

As an alternate to using the help package, online documentation is available from three individual doctrings
by using

print adamsregrid.Regrid.__doc__ -- documentation for the module.
print adamsregrid.Regrid.__init__.__doc__ -- documentation for making an instance.
print adamsregrid.Regrid.rgrd.__doc__ -- documentation for the rgrd method.

TESTING

After importing adamstest, typing

cdat adamstest.py

generates some testing of the adamsregridmodule using analytical functions as fields. It also
writes a hard copy of the documentation to the file regridmodule.doc and a copy of the information
displayed on the screen to screen.asc.