If an LF95.FIG file exists in the current directory,
examine its contents to insure that it contains the desired options.
Debugging and diagnostics
For debugging, the following option settings will provide an increased level of
diagnostic ability, both at compile time, and during execution:
-chk -g -stchk -trace -w -info
The -pca option may be additionally be
used to check for corruption of constant arguments; if the results are
correct with -pca but bad with
-npca a constant argument has been corrupted.
For further analysis during development, consider specifying any of the
-ap -chkglobal -co -cover -f95 -lst -wo -xref
(Note: Specifying -chkglobal or
-chk (x) must be used for compilation of all
files of the program, or incorrect results may occur.)
For production code, we recommend the following option settings:
-nap -nchk -nchkglobal -ncover -ndal -ng -o1 -npca -nsav -nstchk -ntrace
Use -tp, -tpp,
depending on your preferred target processor.
- Use of -tpp will require that the program
be run on a Pentium pro processor or later.
- Use of -tp4 will require that the program
be run on a Pentium 4 processor or later.
If the program performs many I/O operations, consider tuning the blocksize with
the -block option.
Programs may be tuned with the -o2,
-inline options to increase optimization
and to inline code and data.
If the target processor is a Pentium III or Athlon, consider experimenting with
-prefetch 1 or
-prefetch 2 options to select the one which
provides the best performance.
If the target processor is a Pentium 4, consider tuning with the
If optimization produces radically different results or causes runtime errors,
try compiling with -info to see exactly
which steps are being taken to optimize. The
-info option also generates warnings on
sections of code that are unstable and therefore may cause problems when
optimized. A common example of such code is an IF statement that compares
floating-point variables for equality. When optimization seems to alter
the results, try using the -ap option
to preserve arithmetic precision while still retaining some optimization.