sahilm89/lhsmdu: Latin Hypercube Sampling with Multi-Dimensional Uniformity (LHSMDU): Speed Boost minor compatibility fixes

Moza, Sahil

doi:10.5281/zenodo.3929531

Cited by 9 publications

(5 citation statements)

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“…There are many techniques for ensuring spatial uniformity in multidimensional spaces. We adopt the scheme described in Deutsch & Deutsch (2012), as implemented in the LHSMDU Python package (Moza 2020). This procedure results in models that span a more continuous range of values than a regular grid and are more uniformly spaced than random sampling.…”

Section: Parameter Search Using Latin Hypercube Samplingmentioning

confidence: 99%

Triaxial Orbit-based Dynamical Modeling of Galaxies with Supermassive Black Holes and an Application to Massive Elliptical Galaxy NGC 1453

Quenneville

Liepold

2022

ApJ

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Most stellar-dynamical determinations of the masses of nearby supermassive black holes (SMBHs) have been obtained with the orbit superposition technique under the assumption of axisymmetry. However, few galaxies—in particular massive early-type galaxies—obey exact axisymmetry. Here we present a revised orbit superposition code and a new approach for dynamically determining the intrinsic shapes and mass parameters of triaxial galaxies based on spatially resolved stellar kinematic data. The triaxial TriOS code described here corrects an error in the original van den Bosch et al. code that gives rise to incorrect projections for most orbits in triaxial models and can significantly impact parameter search results. The revised code also contains significant improvements in orbit sampling, mass constraints, and run time. Furthermore, we introduce two new parameter-searching strategies—a new set of triaxial shape parameters and a novel grid-free sampling technique—that together lead to a remarkable gain in efficiency in locating the best-fit model. We apply the updated code and search method to NGC 1453, a fast-rotating massive elliptical galaxy. A full 6D parameter search finds p = b / a = 0.933 − 0.015 + 0.014 and q = c/a = 0.779 ± 0.012 for the intrinsic axis ratios and T = 0.33 ± 0.06 for the triaxiality parameter. Despite the deviations from axisymmetry, the best-fit SMBH mass, stellar mass-to-light ratio, and dark matter enclosed mass for NGC 1453 are consistent with the axisymmetric results. More comparisons between axisymmetric and triaxial modeling are needed before drawing general conclusions.

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Section: Parameter Search Using Latin Hypercube Samplingmentioning

confidence: 99%

Triaxial Orbit-based Dynamical Modeling of Galaxies with Supermassive Black Holes and an Application to Massive Elliptical Galaxy NGC 1453

Quenneville

Liepold

2022

ApJ

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“…Second, to explore how the CTF enables us to re-use past execution data to infer the outcome of metamorphic test cases, we simulated an observational data set comprising 1000 executions of the PLT model. To produce this data set, we generated 1000 random input configurations using Latin hypercube sampling [30,67] over the distributions 𝑊 , 𝐻 ∼ U(0, 10) and 𝐼 ∼ U(0, 16). This sampling method provides even coverage of the input space and thus reduces our dependence on a statistical model to fill gaps in the data.…”

Section: Testing Activitymentioning

confidence: 99%

Testing Causality in Scientific Modelling Software

Clark

Foster

Prifling

et al. 2023

ACM Trans. Softw. Eng. Methodol.

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From simulating galaxy formation to viral transmission in a pandemic, scientific models play a pivotal role in developing scientific theories and supporting government policy decisions that affect us all. Given these critical applications, a poor modelling assumption or bug could have far-reaching consequences. However, scientific models possess several properties that make them notoriously difficult to test, including a complex input space, long execution times, and non-determinism, rendering existing testing techniques impractical. In fields such as epidemiology, where researchers seek answers to challenging causal questions, a statistical methodology known as Causal Inference has addressed similar problems, enabling the inference of causal conclusions from noisy, biased, and sparse data instead of costly experiments. This paper introduces the Causal Testing Framework: a framework that uses Causal Inference techniques to establish causal effects from existing data, enabling users to conduct software testing activities concerning the effect of a change, such as Metamorphic Testing, a posteriori . We present three case studies covering real-world scientific models, demonstrating how the Causal Testing Framework can infer metamorphic test outcomes from reused, confounded test data to provide an efficient solution for testing scientific modelling software.

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“…In order to efficiently conduct the parametric study in both DWSIM and HYSYS, a python wrapper is made for both simulation tools in a similar fashion as previous studies [19,26,27]. The parametric study is made by random/Monte Carlo sampling using the lhsmdu [28,29] package over 10 independent variables/factors. The independent variables and their bounds are shown in Table 3.…”

Section: Parametric Studymentioning

confidence: 99%

Evaluation of an Open-source Chemical Process Simulator Using a Plant-wide Oil and Gas Separation Plant Flowsheet Model as Basis

Andreasen

2022

Period. Polytech. Chem. Eng.

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In this paper, a detailed evaluation of the open source process simulator DWSIM is presented. Using a previously published simulation model of an oil and gas separation plant, the results obtained with DWSIM are compared to a commercial process simulator widely used in the industry. The modelled flow scheme comprises a vast number of unit operations including separators (flash vessels), valves, splitters, mixers, compressors, heat exchangers, pumps and recycles (tear streams). The results obtained with DWSIM both for characterization of the inlet fluid as well as for a single operating state for the entire process, compare very well with the data obtained using a commercial tool. A rigorous comparison is made and generally, compared results are within 1% in deviation with a few exceptions. Further, an elaborate comparison is made for over 90 simulations with different settings where 10 independent variables are randomly varied over a wide range. Again, good agreement is found between the two tools. The results are very encouraging and provide fidelity in the use of the investigated open source process simulation tools in a professional environment.

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sahilm89/lhsmdu: Latin Hypercube Sampling with Multi-Dimensional Uniformity (LHSMDU): Speed Boost minor compatibility fixes

Cited by 9 publications

References 0 publications

Triaxial Orbit-based Dynamical Modeling of Galaxies with Supermassive Black Holes and an Application to Massive Elliptical Galaxy NGC 1453

Triaxial Orbit-based Dynamical Modeling of Galaxies with Supermassive Black Holes and an Application to Massive Elliptical Galaxy NGC 1453

Testing Causality in Scientific Modelling Software

Evaluation of an Open-source Chemical Process Simulator Using a Plant-wide Oil and Gas Separation Plant Flowsheet Model as Basis

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