Computer Physics Communications Program LibraryPrograms in Physics & Physical Chemistry |

[Licence| Download | New Version Template] adfj_v1_0.gz(9 Kbytes) | ||
---|---|---|

Manuscript Title: Calculation of general recoupling coefficients using graphical
methods. | ||

Authors: V. Fack, S.N. Pitre, J. Van der Jeugt | ||

Program title: NEWGRAPH | ||

Catalogue identifier: ADFJ_v1_0Distribution format: gz | ||

Journal reference: Comput. Phys. Commun. 101(1997)155 | ||

Programming language: C. | ||

Computer: 486-based PCs. | ||

Operating system: MS-DOS, Linux, Unix. | ||

Keywords: General purpose, Rotation group, Atomic structure, Nuclear structure, Scattering, General recoupling Coefficient, Angular momentum, Racah coefficient, Sn-j coefficient, Coupling tree, Binary trees, Yutsis graphs. | ||

Classification: 4.1. | ||

Subprograms used: | ||

Cat
Id | Title | Reference |

ADBA_v1_0 | NJSUMMATION, NJSUMPAR | CPC 86(1995)105 |

Nature of problem:A general recoupling coefficient for an arbitrary number of (integer or half-integer) angular momenta is expressed as a multiple sum over products of 6-j coefficients, including phase factors and square root factors. This summation formula can then be evaluated for given values of the angular momenta (for this purpose we use the program NJSUMMATION [4]). | ||

Solution method:A summation formula for a general recoupling coefficient is obtained by representing the coefficient by a Yutsis graph, and by performing a number of reduction rules valid for such graphs. Each reduction rule contributes to the final summation formula either just by a numerical factor, or else by an additional summation variable. The purpose is to find an optimal summation formula, i.e. with a minimum number of summation variables. With this in mind special attention is paid to implementing the graphical rules whereby N-cycles are reduced in the most optimal way. | ||

Unusual features:The program has been tested using the Linux [1] operating system. The compilers TURBO C++ [2], GNU CC [3] and SPARCompiler C were used. | ||

Running time:less than 0.1 s on a 486-based PC running Linux. | ||

References: | ||

[1] | Linux version 2.0.0 (Unix clone for 386/486-based PCs); publicly available via the Internet, see e.g. http://www.yahoo.com/Computers/Operating_Systems/Unix/Linux/. | |

[2] | Turbo C++ version 1.01, User Guide (Borland, 1990). | |

[3] | GNU CC version 2.5 (Free Software Foundation, Cambridge, MA, USA); publicly available via the Internet, see e.g. http://www.gnu.ai.mit.edu/home.html. | |

[4] | V. Fack, S.N. Pitre, J. Van der Jeugt, Comput. Phys. Commun. 86(1995)105. |

Disclaimer | ScienceDirect | CPC Journal | CPC | QUB |