Program development tools
We highly recommend that you use makefiles and an appropriate
source code control system (like CVS) to save time maintaining
complex programs.
The unix make utility lets you recompile only the source code with
a more recent creation date than corresponding object files. If no
compilation errors are encountered, then make will subsequently proceed
to build a clean executable. Make is extremely useful for changing
compiler options to do profiling, optimization, and/or debugging.
GNU's automake is available for automatic makefile generation.
The following makefile example is short and simple. It demonstrates
using the make command to build a mixed Fortran 77/C application.
The executable generated by this simple makefile can be used to help
diagnose how well an MPI program is performing. It reports on the
performance of intra-node floating-point operations and inter-node
communication. The code is set up to run on two nodes, but can be
expanded to run on any number of nodes by changing the "MP_" variables
in the env.csh or env.ksh file. To test more than 16 nodes, change the
"NMACH=" variable in the makefile.
The example is contained in
/usr/local/examples/makefiles/node_test.tar on lightning.
Un-tar it in a convenient directory such as your home directory or
in /ptmp/$LOGNAME. To make the executable "drv", type 'make'. To
run the executable and understand the reports it generates, read
the README file.
These are the contents of the makefile:
# The makefile should contain a set of suffix rules. All suffixes must
# be defined. In this case we will have .o for object files, .c for
# C files, and .f for Fortran files.
.SUFFIXES: .o .c .f
# Define the C and Fortran compilers to be used in this makefile:
CC=mpicc -c
FC=mpif90 -c
# Define flags to be used by the C and Fortran compilers:
CFLAGS =
FFLAGS =
# Define include to be used by the C and Fortran compilers:
C_INCLUDES =
F_INCLUDES =
# The linker executable in this case must be the MPI Fortran compiler
# to build a mixed C and Fortran MPI code:
LINK = mpif90
# Define values of parameters that appear in the source codes:
DEFINES =
# Define the list of object files for the linker. The linker will use
# those files to build the executable.
OBJECTS = newdrv.o etime.o flop.o
# The rule that makes the drv executable (note that libraries have
# been specified by the mpif90 linker):
drv: $(OBJECTS)
$(LINK) -o drv $(OBJECTS)
# The rule that makes all object files from C sources:
.c.o:
$(CC) $(CFLAGS) $(C_INCLUDES) $(DEFINES) $<
# The rule that makes all object files from Fortran sources:
.f.o:
$(FC) $(FFLAGS) $(F_INCLUDES) $<
# The rule for deleting object files no longer needed after using
# make for drv:
clean:
rm *.o drv
Important notes about makefile construction:
Programmers often write makefiles to the specification
defined by GNU. If these makefiles don't function correctly, try
using the gnumake tool provided in /usr/local/bin/gmake.
This often needs to be in included in $PATH environment path
before /usr/local/bin to work correctly. In general, do not hard-code makefiles with MPI-related
include paths, library paths, or library names. This can cause
problems because the scripts are designed to provide the correct
paths and libraries even if there are changes from one release
to another or differences for signal vs. threads. When a makefile
is hard-coded, any attempt Linux makes to keep such changes
transparent to users is defeated.
A source code control system (we recommend CVS) provides the
capability to build and maintain large, complex source code
libraries and datasets. Detailed information about CVS is
provided in the CVS man page and on the
CVS documentation page.
Note: You can centralize and maintain your CVS
repository on your local system via SSH.
The tools provided on lightning for code debugging and
improvement include the pgdbx debugger (isolates code faults) and
the pgprof profiler (identifies how your code uses computing
resources).
The pgdbx debugger is from the
PGI Server suite.
The pgprof profiler is from the
PGI Server suite.
Compiler-loader options are available for trapping
floating-point exceptions in your code.
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If you have questions about this document, please contact
CISL Customer Support.
You can also reach us by telephone 24 hours a day, seven days a week at
303-497-1278.
Additional contact methods:
consult1@ucar.edu
and during
business hours
in NCAR Mesa Lab Suite 39.
© Copyright 2004-2005. University Corporation for Atmospheric
Research (UCAR). All Rights Reserved.
Address of this page:
http://www.cisl.ucar.edu/docs/lightning/tools.jsp
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