CAEToR issues related MPI

I have compiled and installed CASToR software on my computer (OS: Ubuntu 20.04 LTS) using the provided Makefile according to the relevant instructions in Section III of General Documentation. During compilation, I set the values of environment variables CASTOR_MPI and CASTOR_OMP related to MPI to 1, and MPICH 3.3.2 and openMPI 4.1.4 are also installed on my computer. Although I successfully installed CASToR software, when I used the following commands to reconstruct an PET image, I found that the time consumed by castor-recon (installed by myself) was much longer than the castor-recon_ unix64 (binary executable provided by official)。

>> castor-recon -df XXX_df.Cdh -opti MLEM -it 10:16 -proj joseph -conv gaussian,4.,4.5,3.5::psf -dim 128,128,64 -vox 3.2,3.2,4.3 -dout recon_img_1

>> castor-recon_unix64 -df XXX_df.Cdh -opti MLEM -it 10:16 -proj joseph -conv gaussian,4.,4.5,3.5::psf -dim 128,128,64 -vox 3.2,3.2,4.3 -dout recon_img_1

For example, for sensitivity generation, castor-recon takes 13659 seconds, while castor-recon_unix64 takes only 5333 seconds.

I’m very suspicious that MPI is not used when executing castor-recon program. Where should I explicitly specify to enable MPI? Or, did I make any mistakes when compiling?

Here are the commands I entered at compile time:

>> export CASTOR_CONFIG=/home/vgate/Software/CASToR_v3.1.1/config

>> export CASTOR_MPI=1

>> export CASTOR_OMP=1

>> export CASTOR_ROOT=1

>> export CASTOR_SIMD=1

>> export CASTOR_VERBOSE=1

>> export CASTOR_DEBUG=1

>> make -j24

I sincerely look forward to your reply!