Note: This post will be moved to Force Field / FF releases / Parsley minor release(s) once it is ready to be shared.
Fitting Data and Results
Fitting targets: 2nd generation training sets (link for the details of the training set generation scheme: http://doi.org/10.5281/zenodo.3777278)
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*Note that there are three uncovered torsion parameters(t114, t125, t146) in the torsion training dataset, which are due to the failed torsiondrive calculation carried out inside QCArchive.
Input force field : version 1.1.0 parsley (http://doi.org/10.5281/zenodo.3695094)
The objective function decreased from
8.710e+03to6.843e+03in 31 steps.
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: Based solely on my intuition without no strong evidence, RC2 angle k values for the angle terms(doesn’t change much from 1.1.0 during the optimzation) seem physical; 400kcal/mol/radian2 for angle seems too large compare to other angle k values. Final gradients for the angle k values are also higher in RC1 (a6: 5.580e+00 , a15 : 4.750e+00) compared to the gradients in RC2 (a6: 1.599e+00 , a15 : 1.391e+00): bond/ angle coverage check? -> origin of large k value for a15 (Wed or later today)
: QM vs. MM scatter plot comparison? (Wed or later today)
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Torsion terms with significant different final k values between RC1 and RC2:
t146,t147: 6 periodicitiest15([*:1]-[#6X4;r3:2]-@[#6X4;r3:3]-[*:4]),t16([#6X4;r3:1]-[#6X4;r3:2]-[#6X4;r3:3]-[*:4]): in-ring rotation
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(3) v1.2.0-RC1 vs. v1.2.0-RC2:
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Optimized geometries
Specific improvement in certain functional groups
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(phosphono group, sulfamate acetate) found in RC1 is also
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shown in RC2.
TODO: revert WRMSE → objective value
TODO: implementation of RMSE calculation from FB output
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QM optimized geometry of CC(O)([P@@](=O)(O)[O-])[P@](=O)(O)[O-]. ( orange: MM optimized geometry with v1.1.0 force field, green: v1.2.0-RC1 force field, magenta: v1.2.0-RC2 force field)
(4) v1.2.0-RC1 vs. v1.2.0-RC2: Relative energies between conformers at “QM optimized geometries”
Comparison of performances of RC1 and RC2 in reproducing QM relative energies between conformers was carried out. Two different ways to calculate MM relative energies were used. Two different ways to calculate MM relative energies were used. For the left figure, MM relative energies were calculated by taking a difference between MM energy at each point and MM energy at the QM minimum. And for the right figure, MM relative energies were obtained by taking a difference between MM energy at each point and MM energy at QM minimum. Both candidates have smaller MAD and shorter tails than v1.1.0, indicating slight better performances over v1.1.0.
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