Ammm:Adaptive umbrella sampling: Difference between revisions

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Created page with "= <span style="background-color: rgb(153,204,255)">Multicanonical ensemble </span><br> = 500px <ref>Ulrich H.E. Hansmann a, Yuko Okamoto, Comparative study of multicanonical and simulated annealing algorithms in the protein folding problem. Physica A 212 (1994) 415-437</ref> Image:Umbrella 22.PNG Image:Umbrella 23.PNG Image:Umbrella 24.PNG = <span style="background-color: rgb(153,204,255)">Background of adaptive umbrella sam..."
 
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= <span style="background-color: rgb(153,204,255)">Background of adaptive umbrella sampling </span><br> =
= <span style="background-color: rgb(153,204,255)">Background of adaptive umbrella sampling </span><br> =


[[Image:Adaptive umbrella sampling.pdf]] <ref>MIHALY MEZEI, Adaptive Umbrella Sampling: Self-consistent Determination of the Non-Boltzmann Bias. JOURNAL OF COMPUTATIONAL PHYSICS Vol. 68, No. 1, 1987</ref>  
[[Image:Adaptive umbrella sampling.pdf |500px]] <ref>MIHALY MEZEI, Adaptive Umbrella Sampling: Self-consistent Determination of the Non-Boltzmann Bias. JOURNAL OF COMPUTATIONAL PHYSICS Vol. 68, No. 1, 1987</ref>  


*<span style="font-size: medium">Review of umbrella sampling (more details please refer to Yue's page) </span>
*<span style="font-size: medium">Review of umbrella sampling (more details please refer to Yue's page) </span>
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*<span style="font-size: large">The trial and error method for umbrella sampling </span>
*<span style="font-size: large">The trial and error method for umbrella sampling </span>


<br>[[Image:Umbrella 2.PNG]] [[Image:Umbrella 41.PNG]]  
<br>[[Image:Umbrella 2.PNG]] [[Image:Umbrella 41.PNG]]


= <span style="background-color: rgb(153,204,255)">Theory of adaptive umbrella sampling </span><br> =
= <span style="background-color: rgb(153,204,255)">Theory of adaptive umbrella sampling </span><br> =

Revision as of 15:59, 10 May 2022

Multicanonical ensemble

[1]

Background of adaptive umbrella sampling

[2]

  • Review of umbrella sampling (more details please refer to Yue's page)

    http://water.bme.utexas.edu/wiki/index.php/ABS:Umbrella_sampling_and_WHAM

    Umbrella sampling attempts to overcome the sampling problem by modifying the Hamiltonian so that

    the unfavorable states are sampled sufficiently. The modification can be written as a perturbation.

  • The trial and error method for umbrella sampling


Theory of adaptive umbrella sampling

  • Definitions

  • The outline of the algorithm:

The potential energy as the variable for adaptive umbrella sampling

[3]

[4]

  The potential energy, in contrast to the commonly used umbrella potentials,

  is of particular interest for complex systems because it does not depend on

  assumptions about the geometry nor on a knowledge of the important

  conformations and transition states that are involved in the equilibration.

  • Range of Sampling:

  • Extrapolation of the Umbrella Potential:

Application:Threonine Dipeptide

  • System setup
    • adaptive umbrella sampling runs were performed at 303 K.
    • T-min was set equal to 280 K, while T-max was set equal to 2000 K.
    • V-min ~ V-max set as -50 to 100 kcal/mol.
    • 200 bins.
    • The umbrella potential was represented as a linear combination of 40 trigonometric functions

  • Results


 

References


  1. Ulrich H.E. Hansmann a, Yuko Okamoto, Comparative study of multicanonical and simulated annealing algorithms in the protein folding problem. Physica A 212 (1994) 415-437
  2. MIHALY MEZEI, Adaptive Umbrella Sampling: Self-consistent Determination of the Non-Boltzmann Bias. JOURNAL OF COMPUTATIONAL PHYSICS Vol. 68, No. 1, 1987
  3. Christian Bartels and Martin Karplus, Probability Distributions for Complex Systems: Adaptive Umbrella Sampling of the Potential Energy. J. Phys. Chem. B 1998, 102, 865-880
  4. Christian Bartels and Martin Karplus, Multidimensional Adaptive Umbrella Sampling Applications to Main Chain and Side Chain Peptide Conformations. Journal of Computational Chemistry, Vol. 18, No. 12, 1450-1462(1997)