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NWChem: Open Source High-Performance Computational Chemistry
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Restarting QMD calculations gives erroneous trajectories #720

Open dblinger opened 1 year ago

dblinger commented 1 year ago

Describe the bug QMD (Gaussian basis set ab initio MD) gives incorrect trajectory upon restarting. Atomic positions and momenta are different for a calculation with, e.g., 50 time steps versus a calculation with 25 steps followed by restart-type calculation of an additional 25 steps.

Describe settings used Report all the environment variables used: export NWCHEM_MODULES=smallqm export NWCHEM_TOP=/home/d54/nwchem-7.0.2 export NWCHEM_TARGET=LINUX64 export USE_MPI=y export USE_MPIF=y export USE_MPIF4=y export ARMCI_NETWORK=OPENIB

export BUILD_OPENBLAS=y

export BUILD_SCALAPACK=y

export USE_SCALAPACK=y export USE_64TO32=n

MKL scalapack requires static linking as follows:

export SCALAPACK="-L$MKLROOT/lib/intel64 -Wl,-Bstatic -Wl,--start-group -lmkl_scalapack_ilp64 -lmkl_intel_ilp64 -lmkl_core -lmkl_sequential -lmkl_blacs_openmpi_ilp64 -Wl,--end-group -Wl,-Bdynamic -lpthread -lm" export SCALAPACK_LIB="$SCALAPACK" export SCALAPACK_SIZE=8 export LAPACK_SIZE=8 export BLAS_SIZE=8 export BLASOPT="-L$MKLROOT/lib/intel64 -lmkl_intel_ilp64 -lmkl_core -lmkl_sequential -lmkl_core -liomp5 -lpthread -lm" export LAPACK_LIB="-L$MKLROOT/lib/intel64 -lmkl_intel_ilp64 -lmkl_core -lmkl_sequential -lmkl_core -liomp5 -lpthread -lm"

Report what operating system and distribution you are using: CentOS Linux release 7.9.2009 (Core)

Attach log files Attach as many log files as possible.

To Reproduce

  1. Steps to reproduce the behavior:

Extract attached tarball.

In the extracted directory, enter the "full_trajectory" subdirectory and run "input.nw" to completion. The trajectory data produced by this calculation (test.xyz) will serve as the ground truth.

Run input file "input.nw" in subdirectory "first_half" to completion. Copy test.* from the "first_half" subdirectory into "second_half". Enter the directory "second_half" and run "input.nw" to completion. This is a restart-type job that will append trajectory information to "test.xyz" from the calculation carried out in "first_half".

Observe the discrepancy between the positions and momenta from the un-restarted calculation in "full_trajectory/test.xyz" and those in "second_half/test.xyz" that result from the restart.

  1. Attach all the input files required to run: bug_report.tar.gz

Expected behavior The nuclear positions and momenta should be identical for the restarted and un-restarted QMD calculations.

edoapra commented 1 year ago

@dblinger thank you very much for the detailed bug report.

edoapra commented 1 year ago

@dblinger By any chance, did you try to verify if the bug exists in the current master branch>

dblinger commented 1 year ago

Hi Edo. Sorry, I didn't think to do this before posting. I did just now clone and build the current master branch (commit 9fdbac67c6d2ca39cb196d7b8ff14ac913d1fd93) and I see the same behavior as with the 7.0.2 release.

edoapra commented 1 year ago

Thank you very much for doing this additional testing.

dblinger commented 1 year ago

I should probably acknowledge that I understand that for adiabatic QMD calculations, one can always take the positions and momenta from the last timestep of a prior calculation and prepare input files for a subsequent calculation manually to pick up the propagation where it left off. In this regard, the formal restart capability for QMD would seem to be only a convenience for users. However, in the case of NAMD-type calculations there is no path to read in the initial density matrix if not invoking a restart, so such a workaround is unavailable in that case in my understanding.