START: Smoothed particle hydrodynamics with tree-based accelerated radiative transfer

Kenji Hasegawa; Masayuki Umemura

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START: Smoothed particle hydrodynamics with tree-based accelerated radiative transfer

Kenji Hasegawa, Masayuki Umemura

Instrumentation and Methods for Astrophysics · Submitted 28 May 2010

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim We find that the results agree well with each other if we set the tolerance parameter as < 1.0, and then it demonstrates that START can solve radiative transfer faster without reducing the accuracy.

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arXiv ID1005.5312 (version 1)

Pith ID5E5ZBLLJ, Pith's permanent record of this paper and its review

CitationKenji Hasegawa, Masayuki Umemura. "START: Smoothed particle hydrodynamics with tree-based accelerated radiative transfer." arXiv:1005.5312 (2010). https://pith.science/paper/5E5ZBLLJ

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The compiled record

The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

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Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 7,586 input tokens, $0.0003 reported.

What the abstract itself states, as probabilities: claims first 0.14 · states limitation 0.31 · human participants 0.01 · controlled comparison 0.90 · randomized assignment 0.01 · states quantitative result 0.89 · compares with prior results 0.97 · mentions code or data availability 0.04.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; show every role.

We present a novel radiation hydrodynamics code, START, which is a smoothed particle hydrodynamics (SPH) scheme coupled with accelerated radiative transfer. The basic idea for the acceleration of radiative transfer is parallel to the tree algorithm that is hitherto used to speed up the gravitational force calculation in an N-body system. It is demonstrated that the radiative transfer calculations can be dramatically accelerated, where the computational time is scaled as Np log Ns for Np SPH particles and Ns radiation sources. Such acceleration allows us to readily include not only numerous sources but also scattering photons, even if the total number of radiation sources is comparable to that of SPH particles. Here, a test simulation is presented for a multiple source problem, where the results with START are compared to those with a radiation SPH code without tree-based acceleration. We find that the results agree well with each other if we set the tolerance parameter as < 1.0, and then it demonstrates that START can solve radiative transfer faster without reducing the accuracy. One of important applications with START is to solve the transfer of diffuse ionizing photons, where each SPH particle is regarded as an emitter. To illustrate the competence of START, we simulate the shadowing effect by dense clumps around an ionizing source. As a result, it is found that the erosion of shadows by diffuse recombination photons can be solved. Such an effect is of great significance to reveal the cosmic reionization process.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	We present a novel radiation hydrodynamics code, START, which is a smoothed particle hydrodynamics (SPH) scheme coupled with accelerated radiative transfer.	contribution 0.99	0.90	0.10	asserted 1.00
s1	The basic idea for the acceleration of radiative transfer is parallel to the tree algorithm that is hitherto used to speed up the gravitational force calculation in an N-body system.	method 0.96	0.20	0.04	asserted 1.00
s2	It is demonstrated that the radiative transfer calculations can be dramatically accelerated, where the computational time is scaled as Np log Ns for Np SPH particles and Ns radiation sources.	result 0.95	0.87	0.32	asserted 1.00
s3	Such acceleration allows us to readily include not only numerous sources but also scattering photons, even if the total number of radiation sources is comparable to that of SPH particles.	result 0.42	0.75	0.16	asserted 0.77
s4	Here, a test simulation is presented for a multiple source problem, where the results with START are compared to those with a radiation SPH code without tree-based acceleration.	method 0.82	0.92	0.04	asserted 0.92
s5	We find that the results agree well with each other if we set the tolerance parameter as < 1.0, and then it demonstrates that START can solve radiative transfer faster without reducing the accuracy.	result 0.98	0.96	0.43	asserted 1.00
s6	One of important applications with START is to solve the transfer of diffuse ionizing photons, where each SPH particle is regarded as an emitter.	contribution 0.65	0.33	0.06	asserted 0.91
s7	To illustrate the competence of START, we simulate the shadowing effect by dense clumps around an ionizing source.	contribution 0.50	0.93	0.04	asserted 0.92
s8	As a result, it is found that the erosion of shadows by diffuse recombination photons can be solved.	result 1.00	0.95	0.14	asserted 1.00
s9	Such an effect is of great significance to reveal the cosmic reionization process.	interpretation 1.00	0.24	0.14	asserted 0.98

What kind of paper the classifier reports this is: method or tool 1.00 · evidence from simulation or computation 1.00.

What was examined, and what was not

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arXiv listing abstract v1

not examined

full text
figures and tables
references and citing sentences
relations to other papers

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P abstract

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S sections
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C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

We present a novel radiation hydrodynamics code, START, which is a smoothed particle hydrodynamics (SPH) scheme coupled with accelerated radiative transfer. The basic idea for the acceleration of radiative transfer is parallel to the tree algorithm that is hitherto used to speed up the gravitational force calculation in an N-body system. It is demonstrated that the radiative transfer calculations can be dramatically accelerated, where the computational time is scaled as Np log Ns for Np SPH particles and Ns radiation sources. Such acceleration allows us to readily include not only numerous sources but also scattering photons, even if the total number of radiation sources is comparable to that of SPH particles. Here, a test simulation is presented for a multiple source problem, where the results with START are compared to those with a radiation SPH code without tree-based acceleration. We find that the results agree well with each other if we set the tolerance parameter as < 1.0, and then it demonstrates that START can solve radiative transfer faster without reducing the accuracy. One of important applications with START is to solve the transfer of diffuse ionizing photons, where each SPH particle is regarded as an emitter. To illustrate the competence of START, we simulate the shadowing effect by dense clumps around an ionizing source. As a result, it is found that the erosion of shadows by diffuse recombination photons can be solved. Such an effect is of great significance to reveal the cosmic reionization process.

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References

How the literature uses it

2 arXiv papers cite this in 3 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 1 sentence without a confident label

Uses its method or tool 1 paper

We utilize a hydrodynamic simulation code START, [ref] which employs smoothed particle hydrodynamics (SPH) method.

Survival of Gas in Subhalos and Its Impact on the 21 cm Forest Signals: Insights from Hydrodynamic Simulations · Hydrodynamic simulations · 1.00

Cites it as background 1 paper

To accomplish it, existing approaches (e.g., [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ; [ref] ) to transport ionising photons must often resort to a number of approximations.

Multi-frequency, thermally coupled radiative transfer with TRAPHIC: Method and tests · Introduction · 0.87

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