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Main Authors: Aehle, Max, Novák, Mihály, Vassilev, Vassil, Gauger, Nicolas R., Heinrich, Lukas, Kagan, Michael, Lange, David
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2405.07944
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author Aehle, Max
Novák, Mihály
Vassilev, Vassil
Gauger, Nicolas R.
Heinrich, Lukas
Kagan, Michael
Lange, David
author_facet Aehle, Max
Novák, Mihály
Vassilev, Vassil
Gauger, Nicolas R.
Heinrich, Lukas
Kagan, Michael
Lange, David
contents Among the well-known methods to approximate derivatives of expectancies computed by Monte-Carlo simulations, averages of pathwise derivatives are often the easiest one to apply. Computing them via algorithmic differentiation typically does not require major manual analysis and rewriting of the code, even for very complex programs like simulations of particle-detector interactions in high-energy physics. However, the pathwise derivative estimator can be biased if there are discontinuities in the program, which may diminish its value for applications. This work integrates algorithmic differentiation into the electromagnetic shower simulation code HepEmShow based on G4HepEm, allowing us to study how well pathwise derivatives approximate derivatives of energy depositions in a sampling calorimeter with respect to parameters of the beam and geometry. We found that when multiple scattering is disabled in the simulation, means of pathwise derivatives converge quickly to their expected values, and these are close to the actual derivatives of the energy deposition. Additionally, we demonstrate the applicability of this novel gradient estimator for stochastic gradient-based optimization in a model example.
format Preprint
id arxiv_https___arxiv_org_abs_2405_07944
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimization Using Pathwise Algorithmic Derivatives of Electromagnetic Shower Simulations
Aehle, Max
Novák, Mihály
Vassilev, Vassil
Gauger, Nicolas R.
Heinrich, Lukas
Kagan, Michael
Lange, David
Computational Physics
Among the well-known methods to approximate derivatives of expectancies computed by Monte-Carlo simulations, averages of pathwise derivatives are often the easiest one to apply. Computing them via algorithmic differentiation typically does not require major manual analysis and rewriting of the code, even for very complex programs like simulations of particle-detector interactions in high-energy physics. However, the pathwise derivative estimator can be biased if there are discontinuities in the program, which may diminish its value for applications. This work integrates algorithmic differentiation into the electromagnetic shower simulation code HepEmShow based on G4HepEm, allowing us to study how well pathwise derivatives approximate derivatives of energy depositions in a sampling calorimeter with respect to parameters of the beam and geometry. We found that when multiple scattering is disabled in the simulation, means of pathwise derivatives converge quickly to their expected values, and these are close to the actual derivatives of the energy deposition. Additionally, we demonstrate the applicability of this novel gradient estimator for stochastic gradient-based optimization in a model example.
title Optimization Using Pathwise Algorithmic Derivatives of Electromagnetic Shower Simulations
topic Computational Physics
url https://arxiv.org/abs/2405.07944