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MASAMB 2016 Efficient Parameter Estimation for ODE Models from Relative Data Using Hierarchical Optimization Sabrina Krause, Carolin Loos, Jan Hasenauer Helmholtz Zentrum Mnchen Institute of Computational Biology Data-driven


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Efficient Parameter Estimation for ODE Models from 
 Relative Data Using Hierarchical Optimization

Sabrina Krause, Carolin Loos, Jan Hasenauer
 Helmholtz Zentrum München Institute of Computational Biology
 
 Data-driven Computational Modelling

Cambridge, 02/10/16

MASAMB 2016

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Parameter Estimation

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Parameter Estimation

ODE model: dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = h(θ, x(t, θ))

  • bservables
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Parameter Estimation

ODE model: dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = h(θ, x(t, θ))

  • bservables

Measurements: ¯ yk = h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt

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Parameter Estimation

Measurements: Maximize the likelihood function: ODE model: dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = h(θ, x(t, θ))

  • bservables

¯ yk = h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt max

θ

  • p(D|θ) =
  • k

1 √ 2πσ2 exp

  • −1

2 ¯ yk − h(θ, x(tk, θ)) σ 2

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SLIDE 6

Parameter Estimation

Minimize the negative log likelihood function: Measurements: ODE model: dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = h(θ, x(t, θ))

  • bservables

¯ yk = h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt min

θ

  • J(θ) = 1

2

  • k

log(2πσ2) + ¯ yk − h(θ, x(tk, θ)) σ 2

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SLIDE 7

Parameter Estimation

Minimize the negative log likelihood function: Measurements: ODE model: dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = h(θ, x(t, θ))

  • bservables

Optimization problem with nθ parameters min

θ

  • J(θ) = 1

2

  • k

log(2πσ2) + ¯ yk − h(θ, x(tk, θ)) σ 2 ¯ yk = h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt

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SLIDE 8

parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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SLIDE 14

parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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SLIDE 16

parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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SLIDE 17

parameter 1 parameter 2 time

  • utput

Multi-Start Optimization

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SLIDE 18

parameter 1 parameter 2 time

  • utput
  • ptimizer runs

negative log-likelihood

global

  • ptimum
  • 1. local
  • ptimum

Multi-Start Optimization

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SLIDE 19

parameter 1 parameter 2 time

  • utput
  • ptimizer runs

negative log-likelihood

global

  • ptimum
  • 1. local
  • ptimum

https://github.com/ICB-DCM/PESTO https://github.com/ICB-DCM/AMICI

Multi-Start Optimization

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SLIDE 20

Parameter Estimation

Minimize the negative log likelihood function: Measurements: ODE model: dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = h(θ, x(t, θ))

  • bservables

Optimization problem with nθ parameters min

θ

  • J(θ) = 1

2

  • k

log(2πσ2) + ¯ yk − h(θ, x(tk, θ)) σ 2 ¯ yk = h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt

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SLIDE 21

Problem Statement

ODE model: Measurements that provide relative data: with unknown variance σ2 of the measurement noise and unknown proportionality factor c dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = c·h(θ, x(t, θ))

  • bservables

¯ yk = c·h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt

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SLIDE 22

Standard Approach

Minimize the negative log likelihood function: ODE model: Measurements that provide relative data: with unknown variance σ2 of the measurement noise and unknown proportionality factor c dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = c·h(θ, x(t, θ))

  • bservables

¯ yk = c·h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt min

θ,c,σ2

  • J(θ, c, σ2) = 1

2

  • k

log(2πσ2) + ¯ yk − c·h(θ, x(tk, θ)) σ 2

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SLIDE 23

Standard Approach

Minimize the negative log likelihood function: ODE model: Measurements that provide relative data: with unknown variance σ2 of the measurement noise and unknown proportionality factor c dx dt = f(θ, x(t, θ)), x(0, θ) = x0(θ) dynamics y(t) = c·h(θ, x(t, θ))

  • bservables

min

θ,c,σ2

  • J(θ, c, σ2) = 1

2

  • k

log(2πσ2) + ¯ yk − c·h(θ, x(tk, θ)) σ 2 Number of parameters: nθ+ number of proportionality factors + number of variances ¯ yk = c·h(θ, x(tk, θ)) + εk, εk ∼ N(0, σ2), k = 1, . . . , nt

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SLIDE 24

Hierarchical Approach

Hierarchical optimization problem: min

θ

  • min

c,σ2

  • J(θ, c, σ2) = 1

2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2

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SLIDE 25

Hierarchical Approach

In each step of the optimization:

  • 1. Calculate optimal proportionality

factors and variances analytically for a given θ

  • 2. Use analytical results to do the

update step in the outer optimiza- tion to estimate the remaining dynamical parameters min

c,σ2

min

θ

update θ current θ compute optimal c and σ2

Hierarchical optimization problem: min

θ

  • min

c,σ2

  • J(θ, c, σ2) = 1

2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2

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SLIDE 26

Hierarchical Approach

In each step of the optimization:

  • 1. Calculate optimal proportionality

factors and variances analytically for a given θ

  • 2. Use analytical results to do the

update step in the outer optimiza- tion to estimate the remaining dynamical parameters min

c,σ2

min

θ

update θ current θ compute optimal c and σ2

Hierarchical optimization problem: Advantage: Outer optimization problem has nθ parameters min

θ

  • min

c,σ2

  • J(θ, c, σ2) = 1

2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2

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SLIDE 27

Analytical Derivation of the Proportionality Factors and Variances

Necessary first order optimality condition: Is (ˆ θ, ˆ c, ˆ σ

2)T a local minimum of J, with J continuously differentiable, then

J(ˆ θ, ˆ c, ˆ σ

2) = 0.

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SLIDE 28

Analytical Derivation of the Proportionality Factors and Variances

Necessary first order optimality condition: Is (ˆ θ, ˆ c, ˆ σ

2)T a local minimum of J, with J continuously differentiable, then

J(ˆ θ, ˆ c, ˆ σ

2) = 0.

J(θ, c, σ2) = 1 2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2

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SLIDE 29

Analytical Derivation of the Proportionality Factors and Variances

Necessary first order optimality condition: Is (ˆ θ, ˆ c, ˆ σ

2)T a local minimum of J, with J continuously differentiable, then

J(ˆ θ, ˆ c, ˆ σ

2) = 0.

J(θ, c, σ2) = 1 2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2 ∂J ∂c

  • (θ,ˆ

c,ˆ σ2) !

= 0 − 1 ˆ σ

2

  • k

¯ ykh(θ, x(tk, θ)) − ˆ c · h(θ, x(tk, θ))2 = 0

  • k

¯ ykh(θ, x(tk, θ)) = ˆ c

  • k

h(θ, x(tk, θ))2

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SLIDE 30

Analytical Derivation of the Proportionality Factors and Variances

Necessary first order optimality condition: Is (ˆ θ, ˆ c, ˆ σ

2)T a local minimum of J, with J continuously differentiable, then

J(ˆ θ, ˆ c, ˆ σ

2) = 0.

∂J ∂c

  • (θ,ˆ

c,ˆ σ2) !

= 0 − 1 ˆ σ

2

  • k

¯ ykh(θ, x(tk, θ)) − ˆ c · h(θ, x(tk, θ))2 = 0

  • k

¯ ykh(θ, x(tk, θ)) = ˆ c

  • k

h(θ, x(tk, θ))2 J(θ, c, σ2) = 1 2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2 ˆ c(θ) =

  • k

¯ ykh(θ, x(tk, θ))

  • k

h(θ, x(tk, θ))2

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SLIDE 31

Analytical Derivation of the Proportionality Factors and Variances

Necessary first order optimality condition: Is (ˆ θ, ˆ c, ˆ σ

2)T a local minimum of J, with J continuously differentiable, then

J(ˆ θ, ˆ c, ˆ σ

2) = 0.

J(θ, c, σ2) = 1 2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2

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SLIDE 32

Analytical Derivation of the Proportionality Factors and Variances

Necessary first order optimality condition: Is (ˆ θ, ˆ c, ˆ σ

2)T a local minimum of J, with J continuously differentiable, then

J(ˆ θ, ˆ c, ˆ σ

2) = 0.

J(θ, c, σ2) = 1 2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2 ∂J ∂σ2

  • (θ,ˆ

c,ˆ σ2) !

= 0 1 2ˆ σ

2

  • k

1 − ¯ yk − ˆ c · h(θ, x(tk, θ)) 2 ˆ σ

2

= 0

  • k

1 = 1 ˆ σ

2

  • k

¯ yk − ˆ c · h(θ, x(tk, θ)) 2

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SLIDE 33

Analytical Derivation of the Proportionality Factors and Variances

Necessary first order optimality condition: Is (ˆ θ, ˆ c, ˆ σ

2)T a local minimum of J, with J continuously differentiable, then

J(ˆ θ, ˆ c, ˆ σ

2) = 0.

J(θ, c, σ2) = 1 2

  • k

log(2πσ2) + ¯ yk − c · h(θ, x(tk, θ)) σ 2 ∂J ∂σ2

  • (θ,ˆ

c,ˆ σ2) !

= 0 1 2ˆ σ

2

  • k

1 − ¯ yk − ˆ c · h(θ, x(tk, θ)) 2 ˆ σ

2

= 0

  • k

1 = 1 ˆ σ

2

  • k

¯ yk − ˆ c · h(θ, x(tk, θ)) 2 ˆ σ

2(θ) = 1

nt

  • k

¯ yk − ˆ c · h(θ, x(tk, θ)) 2

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SLIDE 34

Several experiments, observables and replicates

Proportionality factors cil and variances σ2

il for each observable and

replicate, i = 1, . . . , ny, l = 1, . . . , nr Analytical solutions for the proportionality factors and the variances: ˆ σ

2 il(θ) =

  • j∈Ei

ntjil

  • k=1

¯ yjilk − ˆ cil(θ)hji(θ, x(tk, θ)) 2

  • j∈Ei

ntjil ˆ cil(θ) =

  • j∈Ei

ntjil

  • k=1

¯ yjilkhji(θ, x(tk, θ))

  • j∈Ei

ntjil

  • k=1

hji(θ, x(tk, θ))2 J(θ, c, σ2) = 1 2

ne

  • j=1
  • i∈Ij

nrji

  • l=1

ntjil

  • k=1
  • log(2πσ2

il) +

¯ yjilk − cil · hji(θ, x(tk, θ)) 2 σ2

il

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SLIDE 35

JAK-STAT Signaling Pathway

pEpoR

CYTOPLASM NUCLEUS

tSTAT pSTAT

phospho- rylation dimerization nuclear import dissociation + delayed export

p1 p2 p3 p4

R1 R2 R3 R4 R5 R6 R7 R8 R9 R1 R2 R3 R4 R5 R6 R7 R8 R9

nSTAT5 nSTAT4 nSTAT3 nSTAT2 2nSTAT1 npSTAT:npSTAT pSTAT:pSTAT pSTAT STAT nSTAT4 nSTAT3 nSTAT2 nSTAT1 nSTAT5 STAT 2pSTAT pSTAT:pSTAT npSTAT:npSTAT

p1 p2 p2 p4 p4 p4 p4 p4 p4

Fröhlich F et al. (2016) PLoS Comput Biol 12(7)

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SLIDE 36

Fitting and Convergence

20 40 60 0.5 1

Fitting

20 40 60 0.5 1

  • utput

20 40 60

time [min]

0.5 1

hierarchical approach standard approach measurements

Data from: Swaneye et al. (2003) Proc. Natl. Acad.

  • Sci. USA, 10.1073/pnas.0237333100
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SLIDE 37

Fitting and Convergence

20 40 60 0.5 1

Fitting

20 40 60 0.5 1

  • utput

20 40 60

time [min]

0.5 1

hierarchical approach standard approach measurements

Fits of same quality

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SLIDE 38

Fitting and Convergence

20 40 60 0.5 1

Fitting

20 40 60 0.5 1

  • utput

20 40 60

time [min]

0.5 1

hierarchical approach standard approach measurements

Fits of same quality

10 20 30 40 50 60

  • ptimizer runs
  • 100
  • 50

50 100

negative log-likelihood Convergence

hierarchical appoach standard approach

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SLIDE 39

Fitting and Convergence

20 40 60 0.5 1

Fitting

20 40 60 0.5 1

  • utput

20 40 60

time [min]

0.5 1

hierarchical approach standard approach measurements

Fits of same quality

10 20 30 40 50 60

  • ptimizer runs
  • 100
  • 50

50 100

negative log-likelihood Convergence

hierarchical appoach standard approach

Better convergence

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SLIDE 40

Comparison of Computation Times

standard hierarchical 20 40 60 80 100 120 140 160 180 200 cpu time [s] per converged starts Cpu times per converged starts

15 fold

10-1 100 101 102 103 104 105

log

10(cpu time single starts)[s]

2 4 6 8 10 12 14 16 18 20

frequency Cpu time per optimization

standard approach hierarchical approach

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SLIDE 41

Comparison of Computation Times

standard hierarchical 20 40 60 80 100 120 140 160 180 200 cpu time [s] per converged starts Cpu times per converged starts

15 fold

10-1 100 101 102 103 104 105

log

10(cpu time single starts)[s]

2 4 6 8 10 12 14 16 18 20

frequency Cpu time per optimization

standard approach hierarchical approach

Speed up in computation time

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SLIDE 42

Summary

  • Development of an hierarchical approach to parameter estimation for 


models with relative data


  • Analytical derivation of equations for proportionality factors and


variances


  • Implementation of the method

  • Evaluation of the method for JAK-STAT signaling pathway with


better convergence results and a substantial speed up in computation
 time

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SLIDE 43

Acknowledgements

Institute of Computational Biology Jan Hasenauer Carolin Loos Data-driven Computational Modelling

This project has received funding through the European Union's Horizon 2020 research and innovation programme under grant agreement no. 686282