Chapter 8: Data Files
This chapter describes data files that can be used to include data
into GCL jobs. The format of data files is very simple and useful
for most DISLIN plotting routines.
- A data file must begin with the keyword '%GCL-ASC'.
- Each line may contain up to 512 characters.
- Lines are allowed to carry trailing comment fields,
following a double slash (//). Empty lines are also be
interpreted as comment lines.
- A data file can contain an optional header beginning
with the keyword %HEADER. Variables can be defined in
the header in the form name = value, where value is an
integer, a floatingpoint number or a string. Strings
must be enclosed in a pair of either apostrophes or
quotation marks.
- A data field begins with the keyword %DATA. The first
non comment line after %DATA must contain the number of
columns of the data field. The following lines give the
data separated by blanks or commas. Data can be specified
as integer or floatingpoint numbers where floatingpoint
numbers can contain an exponent part.
- Multiple data blocks can be given in one data file.
The following routines handle data files.
D A T F I L
The routine DATFIL opens a file for data input.
- The call is:
- ISTAT = DATFIL (CFIL)
- CFIL
- is the name of the data file. The default
extension is '.gdf' (Graphics Data File).
- ISTAT
- is the returned status. DATFIL returns -1 if it fails,
or zero.
Additional Note:
- GCL searches the current working directory for
the data file. If the search fails, GCL searches
the directory defined by the environment variable GCL_DATA.
D A T C L S
The routine DATCLS closes the current data file.
- The call is:
- ISTAT = DATCLS ()
- ISTAT
- is the returned status. DATCLS returns -1 if it fails,
or zero.
D A T H D R
The routine DATHDR prints the header of a data file on the
screen.
- The call is:
- ISTAT = DATHDR ()
- ISTAT
- is the returned status of DATHDR and can have the
values 0 and -1. On error, DATHDR returns -1.
D A T V A R
The routine DATVAR returns the value of a variable defined
in the header of a data file.
- The call is:
- V = DATVAR (CNAME)
- CNAME
- is the name of the variable.
D A T C N T
The routine DATCNT returns the number of data of the current
data block in a data file.
- The call is:
- N = DATCNT (COPT)
- COPT
- is a string with the values
- = 'ROWS'
- means the number of rows in the
current data block.
- = 'COLUMNS'
- means the number of columns
in the current data block.
- = 'FULL'
- means the number of data in the
current data block.
- = 'BLOCKS'
- means the number of blocks in
the data file.
D A T R A Y
The routine DATRAY creates an array containing a column of
the current data block in a data file.
- The call is:
- XRAY = DATRAY (NCOLUMN)
- NCOLUMN
- defines the column of the data file.
D A T M A T
The routine DATMAT creates an array containing the whole
current data block of the data file.
- The call is:
- XRAY = DATMAT ()
D A T B L K
The routine DATBLK sets the current data block of a data
file.
- The call is:
- ISTAT = DATBLK (NBLOCK)
- NBLOCK
- specifies the current data block.
- ISTAT
- is the returned status. DATBLK returns 0
if the data block NBLOCK is defined, and -1 if NBLOCK
is not defined in the current data file.
%GCL-ASC
%DATA
3 // Number of columns
// x sin(x) cos(x)
0.000000 0.000000 1.000000
14.545455 0.251148 0.967949
29.090910 0.486197 0.873849
43.636364 0.690079 0.723734
58.181820 0.849725 0.527225
72.727272 0.954902 0.296920
87.272728 0.998867 0.047582
101.818184 0.978802 -0.204807
116.363640 0.895994 -0.444067
130.909088 0.755750 -0.654861
145.454544 0.567060 -0.823677
160.000000 0.342020 -0.939693
174.545456 0.095056 -0.995472
189.090912 -0.158001 -0.987439
203.636368 -0.400931 -0.916108
218.181824 -0.618159 -0.786053
232.727280 -0.795762 -0.605610
247.272720 -0.922354 -0.386345
261.818176 -0.989821 -0.142315
276.363647 -0.993838 0.110838
290.909088 -0.934148 0.356886
305.454559 -0.814576 0.580057
320.000000 -0.642788 0.766044
334.545441 -0.429795 0.902926
349.090912 -0.189251 0.981929
360.000000 -0.000000 1.000000
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