The equivalence between two techniques of angular interpolation for the discrete-ordinates method

Chalhoub, E. S.; Garcia, R. D. M.

doi:10.1016/s0022-4073(99)00134-x

Cited by 38 publications

(16 citation statements)

References 21 publications

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“…Regarding our way of analyzing the results for the radiances computed by the codes, we note that while the PNMARK and PEESNA codes possess accurate angular interpolation techniques (the sourcefunction integration technique (Garcia, 2000) and the dummy-node inclusion technique (Chalhoub and Garcia, 2000), respectively) and the LTSN code possesses a simple linear interpolation scheme in , the HYDROLIGHT code does not possess any and restricts the allowed directions to the discrete angles generated by the quad partitioning performed by HYDROLIGHT-1. In principle, this restriction could be overcome by means of an external interpolation scheme, but this could introduce additional errors into the results of HYDROLIGHT.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…In this section, we present a summary of an improved version of the analytical discrete-ordinates method that has been the subject of some recent works (Barichello and Siewert, 1999;Barichello et al, 2000;Chalhoub and Garcia, 2000;Siewert, 2000). In particular, the method incorporates some recently developed techniques for finding particular solutions (Barichello et al, 2000;Siewert, 2000) and dummy-node inclusion (Chalhoub and Garcia, 2000) as its angular interpolation technique.…”

Section: The Analytical Discrete-ordinates Methodsmentioning

confidence: 99%

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A Comparison of Radiances Generated by Selected Methods of Solving the Radiative-Transfer Equation

Chalhoub

Velho

Garcia³

et al. 2003

Transport Theory and Statistical Physics

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In this work we present a comparison of radiances generated by codes that incorporate the following methods of solving the radiative-transfer equation: spherical-harmonics (P N ), analytical discrete-ordinates, LTS N , and invariant imbedding. The aim of this work is to select among the considered methods the most accurate and efficient, for future use in computational solutions of inverse problems in radiative transfer. From the performed comparison, we concluded that the P N and the analytical discrete-ordinates implementations are the most accurate and that analytical discreteordinates is the most efficient one.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: The Analytical Discrete-ordinates Methodsmentioning

confidence: 99%

A Comparison of Radiances Generated by Selected Methods of Solving the Radiative-Transfer Equation

Chalhoub

Velho

Garcia³

et al. 2003

Transport Theory and Statistical Physics

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Section: The As N Methods (Peesna Computational Code)mentioning

confidence: 99%

“…In particular, the method incorporates some recently developed techniques for finding particular solutions (Barichello et al, 2000;Siewert, 2000) and dummy-node inclusion (Chalhoub and Garcia, 2000) as its angular interpolation technique. Note that we only present here a simplified version for treating the type of problems described in the test problem section.…”

Section: The As N Methods (Peesna Computational Code)mentioning

confidence: 99%

Evaluation of radiances generated by solving the radiative-transfer equation with different approaches

Chalhoub¹,

Velho²,

Neto³

2012

J. Braz. Soc. Mech. Sci. & Eng.

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“…The scattering phase function b(t, m, w; m 0 , w 0 ) gives the scattering beam angular distribution, and the source term is S(t, m, w). PEESNA (Chalhoub and Garcia 2000) ad LTSN (Barichello and Vilhena 1993) are analytical methods based on the discrete-ordinate solution of the RTE. As an example of the formers, we can cite Monte Carlo method.…”

Section: Radiative Transfer Equationmentioning

confidence: 99%

Performance Analysis of Radiative Transfer Algorithms for Inverse Hydrologic Optics in a Parallel Environment

Souto

Velho

Stephany

et al. 2004

Transport Theory and Statistical Physics

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Three algorithms for solving the radiative transfer equation (RTE) were studied: Hydrolight, PEESNA, and LTSN. These algorithms correspond, respectively, to implementations of the invariant imbedding, analytical discrete-ordinates, ant LTS N methods. As a first step, the performance of each algorithm was evaluated running in the same sequential machine. The related codes were used in a hydrologic-optics test case for coastal ocean type of water, in order to calculate the surface-emergent radiation intensities (radiances) given the incident radiances and inherent optical properties such as the absorption and the scattering coefficients. Timing and profiling of the three codes was performed in order to evaluate processing times and identify performance bottlenecks. Next, each algorithm was studied concerning the feasibility of its parallelization using the Message Passing Interface (MPI) messagepassing communication library and execution in a distributed-memory machine, a multicomputer based on IA-32 architecture. The three codes perform spatial discretization of the domain and Fourier decomposition of the radiances obtaining independent azimuthal modes. Therefore, an independent RTE can be written for each azimuthal mode and can be assigned to a different processor, in a parallel implementation. The speed-up that can be achieved increases with the fraction of time spent in the azimuthal mode, but total execution time is also an important issue. Results are discussed and further strategies are proposed.

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The equivalence between two techniques of angular interpolation for the discrete-ordinates method

Cited by 38 publications

References 21 publications

A Comparison of Radiances Generated by Selected Methods of Solving the Radiative-Transfer Equation

A Comparison of Radiances Generated by Selected Methods of Solving the Radiative-Transfer Equation

Evaluation of radiances generated by solving the radiative-transfer equation with different approaches

Performance Analysis of Radiative Transfer Algorithms for Inverse Hydrologic Optics in a Parallel Environment

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