Programs in Physics & Physical Chemistry
|[Licence| Download | New Version Template] admg_v3_0.tar.gz(4838 Kbytes)|
|Manuscript Title: SCELib3.0: the new revision of SCELib, the parallel computational library of molecular properties in the Single Center Approach|
|Authors: N. Sanna, I. Baccarelli, G. Morelli|
|Program title: SCELib3.0|
|Catalogue identifier: ADMG_v3_0|
Distribution format: tar.gz
|Journal reference: Comput. Phys. Commun. 180(2009)2544|
|Programming language: C. Compilers used: xlc V8.x, Intel C V10.x, Portland Group V7.x, nvcc V2.x.|
|Computer: All SMP platforms based on AIX, Linux and SUNOS operating systems over SPARC, POWER, Intel Itanium2, X86, em64t and Opteron processors.|
|Operating system: SUNOS, IBM AIX, Linux RedHat (Enterprise), Linux SuSE (SLES).|
|Has the code been vectorised or parallelized?: Yes. 1 to 32 (CPU or GPU) used|
|RAM: Up to 32GB depending on the molecular system and runtime parameters|
|Keywords: Single Center Expansion Library, SCE molecular properties, electronmolecule scattering.|
|PACS: 34.50Gb, 34.80Bm.|
External routines: CUDA libraries (SDK V2.x).
Does the new version supersede the previous version?: Yes
Nature of problem:
In this set of codes an efficient procedure is implemented to describe the wavefunction and related molecular properties of a polyatomic molecular system within the Single Center of Expansion (SCE) approximation. The resulting SCE wavefunction, electron density, electrostatic and correlation/polarisation potentials can then be used in a wide variety of applications, such as electron-molecule scattering calculations, quantum chemistry studies, biomodelling and drug design.
The polycentre Hartee-Fock solution for a molecule of arbitrary geometry, based on linear combination of Gaussian-Type Orbital (GTO), is expanded over a single center, typically the Center Of Mass (C.O.M.), by means of a Gauss Legendre/Chebyschev quadrature over the θ φ angular coordinates. The resulting SCE numerical wavefunction is then used to calculate the one-particle electron density, the electrostatic potential and two different models for the correlation/polarization potentials induced by the impinging electron, which have the correct asymptotic behaviour for the leading dipole molecular polarizabilities.
Reasons for new version:
The present release of SCELib allows the study of larger molecular systems with respect to the previous versions by means of theoretical and technological advances, with the first implementation of the code over a many-core computing system.
Summary of revisions:
The major features added with respect to SCELib Version 2.0 are
Depending on the molecular system under study and on the operating conditions the program may or may not fit into available RAM memory. In this case a feature of the program is to memory map a disk file in order to efficiently access the memory data through a disk device. The parallel GP-GPU implementation limits the number of CPU threads to the number of GPU cores present.
The execution time strongly depends on the molecular target description and on the hardware/OS chosen, it is directly proportional to the (τ,θ,φ) grid size and to the number of angular basis functions used. Thus, from the program printout of the main arrays memory occupancy, the user can approximately derive the expected computer time needed for a given calculation executed in serial mode. For parallel executions the overall efficiency must be further taken into account, and this depends on the no. of processors used as well as on the parallel architecture chosen, so a simple general law is at present not determinable.
|||P. J. Hay and W. R. Wadt, J. Chem. Phys. 82, 270 (1985); W. R. Wadt and P. J. Hay, ibid. 284 (1985); P. J. Hay and W.R. Wadt, ibid. 299 (1985).|
|||M.J. Frisch et al, Gaussian 03, revision C.02, Gaussian, Inc.,Wallingford, CT, 2004.|
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