mirror of https://github.com/QMCPACK/qmcpack.git
78 lines
2.9 KiB
Plaintext
78 lines
2.9 KiB
Plaintext
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===============
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L2 test details
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===============
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The tests include short and long VMC runs for a 4 atom cell of NiO
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with an L2 pseudopotential used for Ni.
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Reference data was generated with runs the same overall length
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(blocks x steps) as those included in ./qmc-ref, but using 10x more blocks
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and 10x fewer steps. Using more blocks reduced the statistical error of
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the error bars, but resulted in output data files that were too large
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to include in the QMCPACK distribution. The reference values and error
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bars were therefore computed from the higher block count runs. The
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included reference runs were confirmed to be consistent with the original
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higher block count runs.
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Version of the code used to create the reference data:
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Git commit 168a57c0e522c5ef9e0e7d96293442688198e24a
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Reference data from the high block count VMC runs is found below:
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LocalEnergy Variance ratio
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NiO-L2-ref -371.119855 +/- 0.001945 16.541242 +/- 0.202857 0.0446
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For comparison, corresponding data for the lower block count VMC
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reference data found in ./qmc-ref is:
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>qmca -e 2 -q ev qmc-ref/NiO-L2-ref*scalar*
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LocalEnergy Variance ratio
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NiO-L2-ref -371.118862 +/- 0.001859 16.427735 +/- 0.104492 0.0443
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>qmca -e 2 -q ts qmc-ref/NiO-L2-ref*scalar*
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NiO-L2-ref TotalSamples = 12774400.000000 +/- 0.000000
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Test input files were created by reducing the number of steps from the
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included reference by a factor of 10 for the "long" tests and by a
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further factor of 10 for the "short" tests.
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Reference values for the mean local energy and variance were taken
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from the high block count reference runs. Expected error bars were
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derived from the high block count data by multiplying the reference
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error bars by a factor of sqrt(10+1) and sqrt(100+1) for the long
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and short tests, respectively. The factor of +1 accounts for the
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error bar intrinsic to the high block count runs.
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The target means and error bars for long and short tests are:
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refmean referr longerr shorterr
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NiO-L2 energy -371.119855 0.001945 0.006451 0.019547
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The number of samples expected from the long and short runs are
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(with all blocks included):
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TotalSamples
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NiO-L2-long 1280000
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NiO-L2-short 128000
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Error bars from typical long and short runs are shown below:
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Typical long run results:
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Energy Variance ratio
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NiO-L2-long -371.126423 +/- 0.006136 16.003283 +/- 0.148233 0.0431
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Typical short run results:
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Energy Variance ratio
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NiO-L2-short -371.123245 +/- 0.018611 15.383094 +/- 0.190840 0.0415
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Rough timings for the tests on a circa 2018 Intel Skylake system are:
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>grep 'Total Exe' *long*/*.out
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long_test/qmc.out: Total Execution time = 1.6918e+02 secs
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>grep 'Total Exe' *short*/*.out
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short_test/qmc.out: Total Execution time = 1.7596e+01 secs
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