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Inherited builds with FCM
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Note! Before running these examples, make sure you have built the model by using the ' |
Example1: Modifying compilation options
HowTo customise compiling OpenIFS explains how environment variables and editing the configuration files can alter the compiler settings for OpenIFS. In this simple example, an inherited build is used to achieve the same effect by creating a separate configuration file.
The advantage of this approach is that the source code and configuration files of OpenIFS are left unaltered and do not need any environment variables to be set.
Create directories for your own configuration files and source code. For example, create 'oifs/mymake' in which to put your own configuration files and 'oifs/mysrc' to put your own source code:
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% cd oifs
% mkdir mysrc mymake
% ls
COPYING ChangeLog INSTALL LICENSE NOTICE README html make mymake mysrc src t21test
% cd mymake |
As usual the OpenIFS source code is in 'src' with the compilation configurations files used by the FCM build software in 'make/fcmcfg'.
In the 'oifs/mymake' directory, create a file called 'change-fcflags.cfg' with the following content:
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use = ../make
include = ../make/fcmcfg/oifs.cfg
# Add array bound checking to some routines for debugging
build.prop{fc.flags}[ifs/phys_radi/uvclr.F90] = $OIFS_FFLAGS -fcheck=bounds |
The 'use' statement tells FCM that a pre-compiled version of OpenIFS exists in the directory '../make'. This pre-compiled version is 'inherited' through the 'use' statement. All targets (i.e. the object files), source and compilation settings are inherited.
Now run the fcm command to build the model with this change (make sure you have already compiled OpenIFS in the normal way in the oifs/make directory as this relies on the .o files being available):
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Note! Before running these examples, make sure you have built the model by using the ' |
Example1: Modifying compilation options
HowTo customise compiling OpenIFS explains how environment variables and editing the configuration files can alter the compiler settings for OpenIFS. In this simple example, an inherited build is used to achieve the same effect by creating a separate configuration file.
The advantage of this approach is that the source code and configuration files of OpenIFS are left unaltered and do not need any environment variables to be set.
Create directories for your own configuration files and source code. For example, create 'oifs/mymake' in which to put your own configuration files and 'oifs/mysrc' to put your own source code:
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% cd oifs
% mkdir mysrc mymake
% ls
COPYING ChangeLog INSTALL LICENSE NOTICE README html make mymake mysrc src t21test
% cd mymake |
As usual the OpenIFS source code is in 'src' with the compilation configurations files used by the FCM build software in 'make/fcmcfg'.
In the 'oifs/mymake' directory, create a file called 'change-fcflags.cfg' with the following content:
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use = ../make
include = ../make/fcmcfg/oifs.cfg
# Add array bound checking to some routines for debugging
build.prop{fc.flags}[ifs/phys_radi/uvclr.F90] = $OIFS_FFLAGS -fcheck=bounds |
The 'use' statement tells FCM that a pre-compiled version of OpenIFS exists in the directory '../make'. This pre-compiled version is 'inherited' through the 'use' statement. All targets (i.e. the object files), source and compilation settings are inherited.
Now run the fcm command to build the model with this change (make sure you have already compiled OpenIFS in the normal way in the oifs/make directory as this relies on the .o files being available):
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% fcm make -v -f change-fcflags.cfg
[init] make
[init] make config-parse
[info] config-file=/openifs/inherit_tests/oifs/mymake/change-fcflags.cfg
[info] config-file= - /openifs/inherit_tests/oifs/make/fcmcfg/oifs.cfg
[info] config-file= - - /openifs/inherit_tests/oifs/make/fcmcfg/x86_64-gnu-opt.cfg
[info] use=/openifs/inherit_tests/oifs/make
[info] sources: total=2192, analysed=0, elapsed-time=0.6s, total-time=0.0s
[info] target-tree-analysis: elapsed-time=13.3s
[info] compile 0.2 M uvclr.o | ||
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% fcm make -v -f change-fcflags.cfg [init] make [init] make config-parse [info] config-file=/openifs/inherit_tests/oifs/mymake/change-fcflags.cfg [info] config-file= - /openifs/inherit_tests/oifs/make/fcmcfg/oifs.cfg [info] config-file= - - /openifs/inherit_tests/oifs/make/fcmcfg/x86_64-gnu-opt.cfg [info] use=/openifs/inherit_tests/oifs/make [info] sources: total=2192, analysed=0, elapsed-time=0.6s, total-time=0.0s [info] target-tree-analysis: elapsed-time=13.3s [info] compile 0.2 M uvclr.o <- ifs/phys_radi/uvclr.F90 [info] link 1.7 M master.exe <- programs/masterifs/phys_radi/uvclr.F90 [info] link compile targets: modified=1, unchanged=2070, total-time=.7 M master.exe <- programs/master.F90 [info] compile targets: modified=1, unchanged=2070, total-time=0.2s [info] compile+ targets: modified=0, unchanged=626, total-time=0.0s [info] ext-iface targets: modified=0, unchanged=1247, total-time=0.0s [info] install targets: modified=0, unchanged=120, total-time=0.0s [info] link targets: modified=1, unchanged=0, total-time=1.7s [info] TOTAL targets: modified=2, unchanged=4063, elapsed-time=25.3s [done] make build # 26.3s [done] make # 26.6s |
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As in the main 'make' directory, FCM has created a 'build' subdirectory which in this case only contains the object file of the routine uvclr and a new executable. You now have the original executable in 'oifs/make/build/bin/master.exe' and this modified one for testing/debugging.
To run this new executable as a test, edit the job script in the t21test directory and alter the line: MASTER= to point to the location of the newly built executable.
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Experiment with this example by adding additional lines in the |
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Experiment with this example by adding additional lines in the To verify the new compiler options are being used add the |
Example 2: Editing existing code
In this example, we'll build on the previous example and edit an existing source file. First make a new directory to hold the modified source code and copy a source file:
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As in example 1, the 'use' statement tells the build command FCM where to find the pre-compiled OpenIFS and all that's needed here are the changes. In this case, we now need to tell FCM where our new source code is using the 'build.source' statement - the special fcm $HERE variable means "the directory which contains this configuration file". As above, weWe'll also change the compiler options for this file. Note we don't need to include the oifs.cfg file as in the previous example, as this file doesn't contain any references to the OIFS_FFLAGS variable.
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Note that FCM has: seen the new version of cnt0.F90, recompiled it and relinked it to the pre-compiled object code in oifs/make. The new executable can be found in the build/bin sub-directory.
A more advanced example with modules
As in example 1, to try out this new executable in the t21test directory edit the script and change the line MASTER= to point to the location of this executable.
A more advanced example with modules
We'll now add to this and change a We'll now add to this and change a fortran file with a MODULE. In this case, FCM will notice that the module interface has changed and recompile all source files (that we have not changed) that 'USE' this module:
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% fcm make -v -f new-src.cfg [init] make [init] make config-parse [info] config-file=/openifs/inherit_tests/oifs/mymake/new-src.cfg [done] make dest-init [init] make build [info] analyse 0.0 newsrc/newsub.F90 [info] analyse 0.0 ifs/module/yemct0.F90 [info] analyse 0.0 ifs/control/cnt0.F90 [info] sources: total=2193, analysed=3, elapsed-time=0.5s, total-time=0.0s [info] target-tree-analysis: elapsed-time=13.2s [info] compile 0.0 M yemct0.o <- ifs/module/yemct0.F90 [info] compile+ 0.0 M yemct0.mod <- ifs/module/yemct0.F90 [info] ext-iface 0.0 U cnt3.intfb.h <- ifs/control/cnt3.F90 [info] compile 0.0 U cnt2.o <- ifs/control/cnt2.F90 [info] ext-iface 0.0 U cnt0.intfb.h <- ifs/control/cnt0.F90 [info] compile 0.1 U cnt3.o <- ifs/control/cnt3.F90 [info] compile 0.1 M cnt0.o <- ifs/control/cnt0.F90 [FAIL] make build # 25.4s [FAIL] make # 25.6s [FAIL] mpif90 -obin/master.exe /media/hugetmp/Backedup/openifs/inherit_tests/oifs/make/build/o/master.o -L/var/tmp/tmpdir/nagcuser/jtmp.6858/LvpNtq0TxD -lmaster -fopenmp /home/rd/openifs/software/grib_api/1.9.18/grib_api-gcc-4.5.0/lib/libgrib_api_f90.a /home/rd/openifs/software/grib_api/1.9.18/grib_api-gcc-4.5.0/lib/libgrib_api.a -L/usr/local/apps/lapack/3.4.1/LP64 -llapack -lblas -lm # rc=1 [FAIL] /var/tmp/tmpdir/nagcuser/jtmp.6858/LvpNtq0TxD/libmaster.a(cnt0.o): In function `cnt0': [FAIL] /media/hugetmp/Backedup/openifs/inherit_tests/oifs/mysrc3/ifs/control/cnt0.F90:101: undefined reference to `newsub_' [FAIL] collect2: ld returned 1 exit status |
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Why? The reason is that the code does not have enough information to determine where the subroutine 'newsub' comes from. As it's not a module (no USE statement), nor has an explicit interface (no #include "newsub.intfb.h") FCM will assume it comes from an external library.
We can correct the problem in two ways.
Solution 1. The preferred way is to add an explicit interface for the subroutine call making it clear the source code is not from an external library. This also has the advantage that the compiler can check arguments passed to the subroutine are correct. Interface files for subroutines are generated automatically by FCM and do not need to be created by the user.
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#include "su0yoma.intfb.h" #include "su0yomb.intfb.h" #include "newsub.intfb.h" ! ------------------------------------------------------------------ call newsub |
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Building the model now works:
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% fcm make -v -f new-src.cfg
[init] make
[init] make build
[info] analyse 0.0 newsrc/newsub.F90
[info] analyse 0.0 ifs/module/yemct0.F90
[info] analyse 0.0 ifs/control/cnt0.F90
[info] sources: total=2193, analysed=3, elapsed-time=0.5s, total-time=0.0s
[info] target-tree-analysis: elapsed-time=13.4s
[info] compile 0.0 M newsub.o <- newsrc/newsub.F90
[info] ext-iface 0.0 M newsub.intfb.h <- newsrc/newsub.F90
[info] compile 0.0 M yemct0.o <- ifs/module/yemct0.F90
[info] compile+ 0.0 M yemct0.mod <- ifs/module/yemct0.F90
[info] ext-iface 0.0 U cnt3.intfb.h <- ifs/control/cnt3.F90
[info] compile 0.0 U cnt2.o <- ifs/control/cnt2.F90
[info] ext-iface 0.0 U cnt0.intfb.h <- ifs/control/cnt0.F90
[info] compile 0.1 U cnt3.o <- ifs/control/cnt3.F90
[info] compile 0.1 M cnt0.o <- ifs/control/cnt0.F90
[info] link 1.7 M master.exe <- programs/master.F90
[info] compile targets: modified=3, unchanged=2069, total-time=0.3s
[info] compile+ targets: modified=1, unchanged=625, total-time=0.0s
[info] ext-iface targets: modified=1, unchanged=1247, total-time=0.0s
[info] install targets: modified=0, unchanged=120, total-time=0.0s
[info] link targets: modified=1, unchanged=0, total-time=1.7s
[info] TOTAL targets: modified=6, unchanged=4061, elapsed-time=25.2s
[done] make build # 25.8s
[done] make # 26.0s |
The compilation now succeeds. Note that as well as analysing the new code, FCM has also compiled newsub.F90 and created the interface for it, newsub.intfb.h (found in the build/include subdirectory).
Solution 2. Another way to correct the problem is to explicitly tell FCM that the master program depends on the code in our new directory. If you have many new source files and they do not use interface statements you will need to use this approach instead (or as well as - we recommend using interfaces wherever possible).
In this case, rather than edit cnt0.F90 (though its still preferable to include the #include "newsub.intfb.h" statement in cnt0.F90), add another statement to the FCM configure file:
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use = ../make
build.source = $HERE/../mysrc
build.ns-incl = newsrc algor ifsaux ifs surf trans openifs programs/master.F90
build.prop{ns-dep.o}[programs/master.F90] = newsrc algor trans surf ifs ifsaux openifs
build.prop{fc.flags}[ifs/control/cnt0.F90] = -g -O1 -fcheck=bounds |
The statement 'build.prop{ns-dep.o}' means the file 'programs/master.F90' depends on the object files (.o) created from the source in the directories listed. By adding the entry 'newsrc' to the list (see the original statement in oifs/make/fcmcfg/oifs.cfg) this will force FCM to compile all the source code it finds in the newsrc directory. If this behaviour is not desired the statement build.ns-excl can be used to list directories and/or files that should be excluded from the compilation.
Tips
We hope these examples serve to illustrate how to alter and add to the OpenIFS source code using FCM and although simple, the examples show the basics on which to build more complex changes. Whether you choose to use inherited builds or work with copies of the code is largely down to personal preference but we offer a number of suggestions to make life easier:
- If not using inherited builds, always work with copies of the code from the main 'src' directory, never edit the files in src directly - unless you are using a source versioning system, tracking changes and integrating new versions of the code is difficult.
- Inherited builds work well with small and large code changes and help to separate code changes and additions. Any code patches to the main src are automatically linked with inherited builds whereas if you maintain separate copies of the source you'll need to update every copy.
- Only copy the FCM configuration files from make/fcmcfg if you need to and then only oifs.cfg rather than the hardware and compiler settings. It helps to keep all hardware & compiler specific configuration files in one place (ie. make/fcmcfg) and either make links to them from other directories or, if you are not using inherited builds, use 'include' statements in your modified oifs.cfg file to always refer to them in the default location make/fcmcfg.
Further reading and help
A more detailed description of the FCM's 'make' command and the syntax of the configuration files can be found in the FCM User's Guide provided by the UK Meteorological Office. Note that OpenIFS only uses the 'make' command and not any other FCM subcommands.
Additional help can be found in the compiling and FCM OpenIFS Frequently Asked Questions page.
The OpenIFS forums can be used to ask questions to the OpenIFS community and support team.
Any questions or problems can also be sent direct to the OpenIFS support team at: openifs-support@ecmwf.int.
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