Model optimization and selection: Variational Approach for Markov Processes (VAMP) Frank Noé (FU Berlin) frank.noe@fu-berlin.de
Motivation How many states? Which features? Which parameters? (x 1 , x 2 , …, x T ) (s 1 , s 2 , …, s T ) 2 ? Ca-coordinates ? transition matrix? 10 ? distances ? 1000 ? contacts ? Parameter optimization Hyperparameter optimization / problem model selection problem
Solving model selection problem requires two ingredients: 1) A score to rank models (MSMs, TICA, etc) by goodness ==> Variational principle 2) A statistical validation method to avoid overfitting ==> Cross-validation https://en.wikipedia.org/wiki/Cross-validation_(statistics)
Slow processes Backward propagator Spectral decomposition Processes: Eigenvalues / timescales κ i-1 Schütte et al: J. Comput. Phys. (1999), Prinz et al.: J. Chem. Phys. 134, p174105 (2011)
Part I : Variational score Noé and Nüske, MMS 11, 635-655 (2013) Nüske et al, JCTC 10, 1739-1752 (2014)
Part I : Variational score Noé and Nüske, MMS 11, 635-655 (2013) Nüske et al, JCTC 10, 1739-1752 (2014)
Part I : Variational score * Noé and Nüske, MMS 11, 635-655 (2013) Nüske et al, JCTC 10, 1739-1752 (2014) *Noé and Clementi, JCTC 11, 5002—5011 (2015)
Variational Approach for Markov processes (VAMP) *
Variational Approach for Markov processes (VAMP) Wu and Noé, arXiv: 1707.04659 (2017) * Noé and Clementi, JCTC 11, 5002-5011 (2015)
Part II : Statistical validation
Part II : Statistical validation
Part II : Statistical validation Cross-validation
Part II : Statistical validation
How many states in BPTI?
Which features for BPTI?
Validation
Acknowledgements Funding Collaborations Funding Cecilia Clementi (Rice University) Vijay Pande (Stanford) Christof Schütte (FU Berlin) Volker Haucke (FMP Berlin) Eric Vanden-Eijnden (Courant NY) Stephan Sigrist (FU Berlin) Thomas Weikl (MPI Potsdam) Oliver Daumke (MDC) Edina Rosta (King’s College London) John Chodera (MSKCC NY) Bettina Keller (FU Berlin) Gianni de Fabritiis (Barcelona)
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