This module write data in ascii format from an "rectilinear
field" data structure.
The disk file is structured to contain information about
the field at the beginning of the file, followed by the
data.
Specifically, the file format this module produces is:
Number of coordinate dimensions: m
Dimension 1: length of dimension 1
Dimension 2: length of dimension 2
.
.
.
Dimension m: length of dimension m
Data Vector Length
Coordinates for dimension 1
Coordinates for dimension 2
.
.
.
Coordinates for dimension m
data
Or, more broadly, the written file is divided into three broad
subsections:
1. header information
2. coordinate information
3. data information
Each of the specification values, number of data dimensions,
length of dimension, and data vector length,
are integers separated by whitespace.
Immediately following the header information is the coordinate
information for the field. The coordinates are logically
organized so that all the X-coordinates are listed first (the number
of X-coordinates is specified by the length of "dimension 1"),
then all the Y-coordinates (length of dimension 2), etc.
After the coordinate information is the data. The data is
organized such that if the data vector length is N, the first
N data items are interpreted as being the data vector at the
first grid location X[0],Y[0]...W[0]; the next N items are
the data vector at the next grid location X[1],Y[0]...W[0].
(The use of X,Y,..W labels for coordinates is for illustration
only.)
See the EXAMPLE section below for more info.
In this example, we have a 2 by 3 grid of 2 vector values.
This two-dimensional dataset represents height and temperature
at each location of a small grid. The comments in the
example below are delimited with double slashes "//". These
should NOT be included in any of your data files.
2 // two data and spatial dimensions
2 // length of first dimension
3 // length of second dimension
2 // data vector length is 2
0.1 15.2 // the two x coordinates
0.3 .2 .6e-3 // the three y coordinates
10 3.1e-2 // data at x[0],y[0]
11 2.9e-2 // data at x[1],y[0]
9 .02 // data at x[0],y[1]
9.5 1.9e-2 // data at x[1],y[1]
8.33 1.99e-2 // data at x[0],y[2]
8.0 .5e-2 // data at x[1],y[2]