Generic datasets

Simulation datasets in any form.

The alchemlyb.generic module features datasets that are MD engine free and can adopt any form. They can be accessed using the following accessor functions:

load_MBAR_BGFS()

Load data set that will fail the MBAR adaptive solver but could done by BGFS.

Difficult case for the adaptive MBAR solver

The pymbar.mbar.MBAR can have difficulty in solving some dataset with the adaptive method, where BFGS is needed.

The usage is like this

>>> import numpy as np
>>> from pymbar import MBAR
>>> from alchemtest.generic import load_MBAR_BGFS
>>> u_nk = np.load(load_MBAR_BGFS()['data']['u_nk'])
>>> N_k = np.load(load_MBAR_BGFS()['data']['N_k'])
>>> solver_options = {"maximum_iterations":10000,"verbose":True}
>>> solver_protocol = {"method":"adaptive","options":solver_options}
>>> mbar = MBAR(u_nk, N_k, solver_protocol=(solver_protocol,))
>>> results, errors = mbar.getFreeEnergyDifferences()

Which will give the pymbar.utils.ParameterError

>>> solver_options = {"maximum_iterations":10000,"verbose":True}
>>> solver_protocol = {"method":"BFGS","options":solver_options}
>>> mbar = MBAR(u_nk, N_k, solver_protocol=(solver_protocol,))
>>> results, errors = mbar.getFreeEnergyDifferences()

Which will work.

generic: MBAR solver stability test

u_nk and N_k files that could be calculated with MBAR using BGFS method but not the adaptive method.

Notes

Data Set Characteristics:
Number of Legs:

N/A

Number of Windows:

1

Length of Windows:

N/A

System Size:

N/A

Temperature:

N/A

Pressure:

1 N/A

Alchemical Pathway:

N/A

Missing Values:

None

Energy unit:

N/A

Time unit:

N/A

Creator:

Z. Wu

Donor:

Ryan S. DeFeveru (defever@nd.edu)

Date:

Oct 2021

License:

CC0 Public Domain Dedication

This dataset was provided by @rsdefever on Github , downloaded and uploaded by Zhiyi Wu (@xiki-tempula).

alchemtest.generic.load_MBAR_BGFS()[source]

Load data set that will fail the MBAR adaptive solver but could done by BGFS.

Returns:

data – Dictionary-like object, the interesting attributes are:

  • ’data’ : the data files for u_nk and N_k

Return type:

Bunch