Submitting a job
Using splash, you can easily submit an ORCA job to Nimbus using only an ORCA input file and a single terminal command.
splash submit <input_file>
Example Submission
In the following example, we submit a geometry optimisation calculation for a benzene molecule.
First, prepare the input file.
benzene.inp !BP86 def2-svp OPT
%PAL NPROCS 16 END
%maxcore 2000
*xyzfile 0 1 benzene.xyz
In this example the structure is located in a separate .xyz file - benzene.xyz.
benzene.xyz 12
Benzene
H 1.2194 -0.1652 2.1600
C 0.6825 -0.0924 1.2087
C -0.7075 -0.0352 1.1973
H -1.2644 -0.0630 2.1393
C -1.3898 0.0572 -0.0114
H -2.4836 0.1021 -0.0204
C -0.6824 0.0925 -1.2088
H -1.2194 0.1652 -2.1599
C 0.7075 0.0352 -1.1973
H 1.2641 0.0628 -2.1395
C 1.3899 -0.0572 0.0114
H 2.4836 -0.1022 0.0205
To submit a job for this calculation, simply run
splash submit benzene.inp
You should then see an message informing you that a submission script was created and subsequently submitted.
The job will be given the same name as your input file, and the output file for this calculation should appear in the current directory when the job starts running - for example
user@nimbus-1-login-1 ~/benzene $ ls
benzene.6718675.e benzene.6718675.o benzene.inp benzene.out benzene.slm benzene.xyz
When the calculation has finished, been evicted, timed-out, or otherwise halted, you should see a new directory in the same location as your input and .xyz files.
This directory will be named <jobname>_results and will contain all of the files that ORCA has created.
user@nimbus-1-login-1 ~/benzene $ ls
benzene.6718675.e benzene.6718675.o ... benzene.xyz benzene_results
Submitting multiple jobs
You can submit more than one calculation at once by providing more than one input file to splash. For example
splash submit input_1.inp input_2.inp
You can even use a wildcard to submit jobs without typing each filename out
splash submit input_*.inp
Note that this will run all jobs in the current directory, and so can produce a large number of files in the same directory.
Coordinates within .inp files
Instead of providing a separate .xyz file, it is possible to specify coordinates within the ORCA input file.
This feature is supported by splash and requires no additional effort on the part of the user.
Providing input orbitals
To provide ORCA with a set of orbitals, make sure you have both the MORead keyword and the %moinp "<gbw_filename>" line in
your input file. Note that ORCA will not allow your specified file to have the same name-stem as the input file.
For the benzene example in the previous section, a correct input file would be
benzene.inp with input orbitals specified !BP86 def2-svp OPT FREQ MORead
%moinp "new_orbs.gbw"
%PAL NPROCS 16 END
%maxcore 2000
*xyzfile 0 1 benzene.xyz
The file <gbw_filename> must be in the same directory as the input file, and cannot contain any path information.
Selecting a compute instance
Specific Nimbus compute instances can be requested using the --instance option.
The full list of ORCA compatible instances currently known to splash are
spot-fsv2-2
spot-fsv2-4
spot-fsv2-8
spot-fsv2-16
spot-fsv2-32
spot-hc-44
spot-hbv2-120
paygo-fsv2-2
paygo-fsv2-4
paygo-fsv2-8
paygo-fsv2-16
paygo-fsv2-32
paygo-hc-44
paygo-hbv2-120
Note
You can only use instances to which you have been granted access.
This is usually indicated by a QOS error at submission time. To resolve this, modify your access
on the RCAM portal.
By default, splash submits to spot-fsv2-16 which has 16 cores and 2GB RAM per core, to change this default for your account
add the following to your ~/.bash_rc file, where <instance> is one of those given above
export SPLASH_DEFAULT_INSTANCE=<instance>
Selecting an ORCA version
Several versions of ORCA are available on Nimbus - use module check <INSTANCE_NAME> ORCA to see the ORCA versions available for a given instance.
Note
You might get an error about termcolor when using module check. If you do, run pip install termcolor and then try again!
Warning
Beware: Not all Nimbus instances have access to the same ORCA versions.
splash contains its own internal list of ORCA modules which can be printed with the splash orca_modules command. This list is periodically updated when new
versions of ORCA are installed on Nimbus, please raise a GitHub Issue to have new modules added to splash’s list.
By default, splash will use the most recent version of ORCA (6.0.1), but a different version can be selected with
the --orca_version <VALUE> optional argument.
Alternatively, to select a new default ORCA version and avoid having to enter this optional argument constantly,
add the following to your ~/.bash_rc file, where <version> is the version number, e.g. 6.0.0
export SPLASH_ORCA_VERSION=<version>
More
Additional command line arguments for splash submit can be listed by running
splash submit -h