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Main purpose of FC2K is to embed native code inside Kepler workflow. This way, you are able to connect various, physics based, calculations into chain of execution. There are few rules you have to follow while embedding native code inside Kepler:
- your Your routine signature must be exactly the same as one suggested by FC2K
- in In order to access IDSes, you have to use IMAS based modules inside your Fortran code
- you You can pass data into and outside of the code in the form of:
- primitive Primitive types
- IDSes
- code Code parameters
- you You should avoid accessing external files unless it's really impossible to run the simulation without external source of data
- all All physics related information should be exchanged only via IDSes
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Source code for this sample can be found at following location
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Make sure to initialise your environment. Follow the steps here: 00. Initial setup or here: 05.3. IMAS - basic topics - environment set-up(POZ'19Oct) | ||
Make sure to initialise test database - it will be used for temporary files
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Preparing the code
First of all, we need simple code that will read data. In this sample, we will use very simple code that reads distribution IDS, shows some info, and output scalar value
Let's say we will retrieve the first time index (as integer) from the array of all times. Remember, this is just an exercise where we want to make all things work together. Don't pay attention to whether it's something meaningful or not. Let's say our actor is supposed to retrieve first time index in the IDS.
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IDS -> actor code [we treat the actor as a black box] -> integer |
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subroutine distributiondisp(distributionin, output) use ids_schemas implicit none type (ids_distribution_sources) :: distributionin integer, intent(out) :: output output = int( distributionin%time(1) ) ! we are reading data from the IDS and return it back to Kepler return end subroutine |
As you can see, we don't even access input data, yet. All we have, so far, is the API of the native code.
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As you recall from previous session (dedicated to FC2K) we have to have library that contains native code we are supposed to run.
Let's prepare it. We will do it, by creating Makefile project - library will be called libdistribution_disp.a
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# In this sample I will use ifort # However, depending on target system (where IMAS is installed) # it might be you have other options as well - e.g.: gfortran, pgi, NAG, etc. F90 = ifort COPTS = -g -O0 -assume no2underscore -fPIC -shared-intel # Note that you should _always_ use pkg-config to obtain # flags for compiler and linker # do not pass hardcoded locations unless it's really unavoidable! LIBS = `pkg-config --libs imas-ifort imas-lowlevel` INCLUDES = `pkg-config --cflags imas-ifort imas-lowlevel` # It is little bit messy here, but we need two different targets # for the purpose of the tutorial # first - builds very basic code that doesn't touch IDSes data # second - builds the code that will read IDSed data # first: distribution_disp.o libdistribution_disp.a second: distribution_disp_2.o all: libdistribution_disp_2.a libdistribution_disp.a: distribution_disp.o ar -rvs libdistribution_disp.a $^ libdistribution_disp_2.a: distribution_disp_2.o ar -rvs libdistribution_disp.a $^ distribution_disp.o: distribution_disp.f90 $(F90) $(COPTS) -c -o $@ $^ ${INCLUDES} $(LIBS) distribution_disp_2.o: distribution_disp_2.f90 $(F90) $(COPTS) -c -o $@ $^ ${INCLUDES} $(LIBS) # try to provide _clean_ target, so you can easily # cleanup source tree clean: rm -f *.o *.a |
Once we run make we can use library inside the project
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> make first ifort -g -O0 -assume no2underscore -fPIC -shared-intel -c -o distribution_disp.o distribution_disp.f90 `pkg-config --cflags imas-ifortifort` imas-lowlevel` `pkg-config --libs imas-ifort imas-lowlevel`ifort` ar -rvs libdistribution_disp.a distribution_disp.o ar: creating libdistribution_disp.a a - distribution_disp.o |
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