John Tramm

Alternative Random Ray Volume Estimators

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# Problem As discussed in more depth in the [OpenMC docs](https://docs.openmc.org/en/stable/methods/random_ray.html#volume-dilemma), the "simulation averaged" volume estimator that OpenMC currently uses as part of the random ray solver has a few...

Random Ray Linear Source

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In the random ray method, the particle flux is treated continuously in space and angle. However, in the current random ray implementation in OpenMC, any scattering or fixed sources are...

Random Ray First Collided Source

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The current fixed source random ray solver implementation in OpenMC (via #2829 and #2988) only allows for user definition of volumetric sources. If other types of sources are needed for...

Currently in OpenMC, both the MGMC mode and random ray both require the user to input multigroup cross sections. This is a generally good policy given the approximations inherent with...

The current implementation of random ray in OpenMC uses a domain replication technique for distributed memory parallelism with MPI. However, in random ray, use of domain replication does not scale...

# Overview Currently, particles starting in regions with very low weight window values may aggressively split shortly after being born. This reduces sampling efficiency as there is no reason to...

Fix Weight Window Infinite Loop Bug

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# The Problem I have been working a lot with weight windows recently, and ran into a case where an infinite loop was triggering on a JET-like model. The particle...

## Bug Description Currently if there are multiple point sources that end up residing within a single subdivided source region, the random ray solver will only use the one with...