An R-matrix package for coupled-channel problems in nuclear physics
An R-matrix package for coupled-channel problems in nuclear physics
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用于核物理中耦合通道问题的 R 矩阵包
DOI：
10.1016/j.cpc.2015.10.015
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
P. Descouvemont
中科院分区：
文献类型：
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作者：
P. Descouvemont
我们提出了一个 R 矩阵 Fortran 包来解决核物理中的耦合通道问题。基函数被选择为拉格朗日函数，它允许对矩阵元素进行简单的计算。主要输入是程序指定的某些核-核距离处的耦合势。该程序提供碰撞矩阵以及可选的相关波函数。本方法同时处理开放通道和封闭通道，没有与封闭通道相关的数值不稳定。它还可以解决非局部势的耦合通道问题。可以使用传播技术来处理长程电势，从而显着加快计算速度。我们首先概述 R 矩阵理论和拉格朗日网格方法。然后提供该软件包及其在 UNIX 计算机上的安装的描述。最后讨论了五个典型例子。程序摘要 程序标题：rmatrix 目录标识符：AEYP_v1_0 程序摘要 URL：http://cpc。 CS。问题。交流。英国/摘要/AEYP_v1_0。 html 程序可从：北爱尔兰贝尔法斯特女王大学 CPC 程序图书馆获取 许可条款：标准 CPC 许可证，http://cpc.html CS。问题。交流。英国/执照/执照。 html 分布式程序行数，包括测试数据等：6090 分布式程序字节数，包括测试数据等：86122 分发格式：tar.gz gz 编程语言：Fortran 90。 RAM：内存使用很大程度上取决于问题的性质（通道数、基础大小）。分类：17.8。外部例程：如果可用，LAPACK 库可用于矩阵求逆（比包中包含的子例程更快）。问题性质：解决正能量的耦合通道问题；该软件包提供给定能量、自旋和宇称的碰撞矩阵和相关波函数。求解方法：耦合通道系统采用R矩阵法求解，采用拉格朗日函数。可以执行 R 矩阵的传播。限制：对于非局部势，不能使用传播技术。运行时间：很大程度上取决于问题的性质。对于单通道计算，运行类型通常小于1 s。对于大规模计算（通常超过 100 个通道），在多 CPU Linux 计算机上运行时间可能会增加长达几分钟。
We present an R-matrix Fortran package to solve coupled-channel problems in nuclear physics. The basis functions are chosen as Lagrange functions, which permits simple calculations of the matrix elements. The main input is the coupling potentials at some nucleus–nucleus distances, specified by the program. The program provides the collision matrix and, optionally, the associated wave function. The present method deals with open and closed channels simultaneously, without numerical instability associated with closed channels. It can also solve coupled-channel problems for non-local potentials. Long-range potentials can be treated with propagation techniques, which significantly speed up the calculations. We first present an overview of the R-matrix theory, and of the Lagrange-mesh method. A description of the package and its installation on a UNIX machine is then provided. Finally, five typical examples are discussed. Program summary Program title: rmatrix Catalogue identifier: AEYP_v1_0 Program summary URL: http://cpc. cs. qub. ac. uk/summaries/AEYP_v1_0. html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc. cs. qub. ac. uk/licence/licence. html No. of lines in distributed program, including test data, etc.: 6090 No. of bytes in distributed program, including test data, etc.: 86122 Distribution format: tar. gz Programming language: Fortran 90. RAM: Memory usage strongly depends on the nature of the problem (number of channels, size of the basis). Classification: 17.8. External routines: If available, the LAPACK library can be used for matrix inversion (faster than the sub-routine included in the package). Nature of problem: Solving coupled-channel problems for positive energies; the package provides the collision matrix and the associated wave function for given energy, spin and parity. Solution method: The coupled-channel system is solved with the R-matrix method, and Lagrange functions are adopted. Propagation of the R-matrix can be performed. Restrictions: For non-local potentials, the propagation technique cannot be used. Running time: strongly depends on the nature of the problem. For single-channel calculations, the running type is typically less than 1 s. For large scale calculations (typically more than 100 channels), the running time may increase up to several minutes on a multi-CPU Linux machine.