Neural Networks for Predicting Algorithm Runtime Distributions - - PowerPoint PPT Presentation

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Neural Networks for Predicting Algorithm Runtime Distributions - - PowerPoint PPT Presentation

Neural Networks for Predicting Algorithm Runtime Distributions Katharina Eggensperger, Marius Lindauer & Frank Hutter Paper ID #2772 Eggensperger, Lindauer and Hutter DistNet: Runtime Distribution Prediction #2772 IJCAI2018 Motivation


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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Neural Networks for Predicting Algorithm Runtime Distributions

Katharina Eggensperger, Marius Lindauer & Frank Hutter Paper ID #2772

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Motivation

Algorithm portfolios yield state-of-the-art performance for SAT, ASP, Planning, … → to build these we can make use of runtime predictions Other applications:

  • Optimal restarts
  • Algorithm selection
  • Algorithm configurations

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Describing the Runtime of an Algorithm?

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solve(instance, seed): # do something return solution, runtime runtime

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Describing the Runtime of an Algorithm?

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solve(instance, seed): # do something return solution, runtime runtime

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Contributions

1 Study how to predict parametric RTDs 2 Propose DistNet, a practical neural network for predicting RTDs 3 Evaluate DistNet and show that it can learn from only a few samples per instance

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Typical Pipeline for Runtime prediction

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Typical Pipeline for Runtime prediction

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Typical Pipeline for Runtime prediction

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Typical Pipeline for Runtime prediction

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Typical Pipeline for Runtime prediction

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Empirical RTDs

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Clasp-factoring LPG-Zenotravel SAPS-CV-VAR p(solved by this time)

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Typical Pipeline for Runtime prediction

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Considered Parametric Distribution

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Quantifying the Quality of Runtime Distributions

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(1)

  • bserved runtimes

distribution parameter

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Quantifying the Quality of Runtime Distributions

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(1) (2)

  • bserved runtimes

distribution parameter

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Typical Pipeline for Runtime prediction

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Predicting multiple Runtime Distributions

Option 1

For each training instance → fit the parametric distribution’s parameter on observed runtimes. Then for all training instances, for each distribution parameter: fit a model

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Predicting multiple Runtime Distributions

Option 1

For each training instance → fit the parametric distribution’s parameter on observed runtimes. Then for all training instances, for each distribution parameter: fit a model

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Problematic, because models

  • can only be as good as each fitted distribution
  • do not know about interaction between their outputs
  • typically minimize loss in the parameter space
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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Predicting multiple Runtime Distributions

Option 2

For each training instance → fit the parametric distribution’s parameter on observed runtimes. Then for all training instances, for each distribution parameter: fit a model with multiple outputs

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Problematic, because model

  • can only be as good as each fitted distribution
  • does not know about interaction between their outputs
  • typically minimizes loss in the parameter space
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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Predicting multiple Runtime Distributions

DistNet

For each training instance → fit the parametric distribution’s parameter on observed runtimes. Then for all training instances, for each distribution parameter: fit a neural network using negative log-likelihood as a loss function

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Results

We compared

  • DistNet
  • independent Random Forests (iRF)
  • multi-output Random Forests (mRF)
  • n 7 scenarios from SAT solving and AI

planning.

16 Table: Averaged negative log-likelihood achieved for predicting RTDs for unseen instances

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Figure: Averaged negative log-likelihood. Smaller values are better.

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Results

We compared

  • DistNet
  • independent Random Forests (iRF)
  • multi-output Random Forests (mRF)
  • n 7 scenarios from SAT solving and AI

planning.

16 Table: Averaged negative log-likelihood achieved for predicting RTDs for unseen instances

[...]

Figure: Averaged negative log-likelihood. Smaller values are better.

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Results

We compared

  • DistNet
  • independent Random Forests (iRF)
  • multi-output Random Forests (mRF)
  • n 7 scenarios from SAT solving and AI

planning. → Predicting parameters for RTDs is possible → Joint predictions work better → DistNet provides more robust predictions which are often better than those of competitors

16 Table: Averaged negative log-likelihood achieved for predicting RTDs for unseen instances

[...]

Figure: Averaged negative log-likelihood. Smaller values are better.

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

DistNet on a Low Number of Observations

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averaged NLLH

multi-ouput Random Forest Distribution fitted on all samples

DistNet

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Wrap-Up

We have proposed DistNet, which + jointly learns distribution parameters + directly optimizes the loss function of interest + performs well even if only few observations per instance are available

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Wrap-Up

We have proposed DistNet, which + jointly learns distribution parameters + directly optimizes the loss function of interest + performs well even if only few observations per instance are available Open Questions:

  • How to automatically determine a well fitting distribution family?
  • How to handle heterogeneous datasets?

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DistNet: Runtime Distribution Prediction #2772 Eggensperger, Lindauer and Hutter IJCAI’2018

Wrap-Up

We have proposed DistNet, which + jointly learns distribution parameters + directly optimizes the loss function of interest + performs well even if only few observations per instance are available Open Questions:

  • How to automatically determine a well fitting distribution family?
  • How to handle heterogeneous datasets?

Code and data: https://www.automl.org/distnet/

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