Hello, Can anybody assist me in expanding the number of cores using gaussian 9.0 program. I have multiprocessor system with Intel® Core™ i5-1135G7 (up to 4.2 GHz with Intel® Turbo Boost Technology, 8 MB L3 cache, 4 cores) and 8GB RAM. I am using Avogadro and Gaussian, so kindly assist me where to put the commands?
Hello, in the input example below the number of cores used is 2 (%NProcShared=2), you can change this value to 4 (since you mention the multiprocessor system you are working with has 4 cores). The %Mem keyword refers to RAM memory.
%NProcShared=2
%Mem=2GB
# HF/6-31G(d)
water energy
0 1
O -0.464 0.177 0.0
H -0.464 1.137 0.0
H 0.441 -0.143 0.0
Alexis is right and the %nproc (or %nprocshared, which is the same) instruction can be used to specify the number of processors (up to 4 in your case). As for the memory, pay attention not to exceed, since managing too a larger amount of RAM can slow down your calculation. See https://nusit.nus.edu.sg/services/hpc-newsletter/running-gaussian-09-jobs-more-efficiently/
The correct amount of memory depends on a number of parameters (including the number of processors, their architecture, the type of basis sets), but it can be easily evaluated with a small free program, gaussmem (https://people.unica.it/marca/category/computational-chemistry/).
I hope this may help!
You can add in the imput file the command line "% nprocshared = x", where x you replace it with the number of nuclei you want. It is worth mentioning that each core will work with an amount of RAM, in this case I suggest adding it manually with the command "% mem = XGB". More information see https://gaussian.com/running/
I am using avogadro to generate input file. Should I put the commands in the input generation window?@ Alexis Antoinette Ann Delgado
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