Vectorizable approach to molecular CI problems using determinantal basis

Zarrabian, Sohrab; Sarma, C. R.; Paldus, Josef

doi:10.1016/0009-2614(89)85346-1

Cited by 100 publications

(30 citation statements)

References 12 publications

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“…This eliminates the communication for 2 . The term 4 involves double excitations of alpha strings and it is treated separately. Intensive network communication occurs here in order to get the remote alpha blocks for the calculation of 4 .…”

Section: Alpha-alpha Routinementioning

confidence: 99%

“…The term 4 involves double excitations of alpha strings and it is treated separately. Intensive network communication occurs here in order to get the remote alpha blocks for the calculation of 4 . The communication is handled in the same way as in the alpha-beta routine, so repeated communication is avoided.…”

Section: Alpha-alpha Routinementioning

confidence: 99%

“…A major step forward in determinant-based FCI was introduced by Handy 2 with the idea of separate alpha and beta strings for alpha and beta spins. Following this innovation, more efficient algorithms have been proposed and implemented, including the work by Olsen et al, 3 Zarrabian et al, 4 Michael et al, 5 Rossi et al, 6 Sherrill et al, 7 Ivanic et al, 9 and others. However, despite the diversity of the algorithms, the implementations of FCI programs remain essentially in two different ways, either the integral driven approach or the configuration driven approach.…”

Section: Introductionmentioning

confidence: 99%

“…Because the FCI calculation is carried out at every CASSCF iteration, considerable effort has been expended to develop and implement efficient FCI algorithms to handle the relatively large active spaces, required by complex chemical systems. [1][2][3][4][5] Because of the simplicity in computing the coupling coefficients, almost all modern FCI algorithms are based on determinants instead of configuration state functions ͑CSFs͒. A major step forward in determinant-based FCI was introduced by Handy 2 with the idea of separate alpha and beta strings for alpha and beta spins.…”

Section: Introductionmentioning

confidence: 99%

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The parallel implementation of a full configuration interaction program

Gan

Alexeev

Gordon

et al. 2003

The Journal of Chemical Physics

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Both the replicated and distributed data parallel full configuration interaction (FCI) implementations are described. The implementation of the FCI algorithm is organized in a hybrid strings-integral driven approach. Redundant communication is avoided, and the network performance is further optimized by an improved distributed data interface library. Examples show linear scalability of the distributed data code on both PC and workstation clusters. The new parallel implementation greatly extends the hardware on which parallel FCI calculations can be performed. The timing data on the workstation cluster show great potential for using the new parallel FCI algorithm in expanding applications of complete active space self-consistent field applications. Keywords Configuration interaction Disciplines Chemistry CommentsThe following article appeared in Journal of Chemical Physics 119 (2003) Both the replicated and distributed data parallel full configuration interaction ͑FCI͒ implementations are described. The implementation of the FCI algorithm is organized in a hybrid strings-integral driven approach. Redundant communication is avoided, and the network performance is further optimized by an improved distributed data interface library. Examples show linear scalability of the distributed data code on both PC and workstation clusters. The new parallel implementation greatly extends the hardware on which parallel FCI calculations can be performed. The timing data on the workstation cluster show great potential for using the new parallel FCI algorithm in expanding applications of complete active space self-consistent field applications.

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Section: Alpha-alpha Routinementioning

confidence: 99%

Section: Alpha-alpha Routinementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The parallel implementation of a full configuration interaction program

Gan

Alexeev

Gordon

et al. 2003

The Journal of Chemical Physics

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“…If singly excited strings are stored according to categories such excitations can simply be eliminated. With suitable string de®nitions and organization, loop structures for the evaluation of r 1 Y r 2 , and r 3 for the RAS expansion require only minor modi®cation to full CI algorithms, a procedure which is well documented in the literature [15,17,19,22].…”

Section: Computational Implementationmentioning

confidence: 99%

The unrestricted natural orbital-restricted active space method: methodology and implementation

Kozłowski

Pulay

1998

Theoretical Chemistry Accounts: Theory, Computation, and Modeli

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The full con®guration interaction method in the space of fractionally occupied unrestricted natural orbitals (UNO-CAS method) is extended to excited states as well as to strongly correlated and reactive systems with large active spaces. This is accomplished by using restricted active space (RAS) wave functions introduced by Olsen et al. [(1988) J Chem Phys 89: 2185] and using the UNOs without the expensive orbital optimization step. In RAS, the space of active orbitals is subdivided into three groups: a group with essentially doubly occupied orbitals (RAS1), the usual CAS space (RAS2), and a space with weakly occupied active orbitals (RAS3). We select these spaces on the basis of the occupation numbers of the UNOs. All possible electron distributions are allowed in the usual CAS space, but the number of vacancies is limited in RAS1 and the number of electrons is limited in RAS3. We discuss an ecient algorithm for generating a RAS wave function. This is based on the Handy-Knowles determinantal expansion with an addressing scheme adopted for the restricted expansion. Results for both ground and excited states of azulene and free base porphyrin are presented.

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Relative stability of the3A2,1A2, and1A1 states of phenylnitrene: A difference-dedicated configuration interaction calculation

Castell

García

et al. 1996

J. Comput. Chem.

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The relative stability of the 3A2, 1A2, and 1A1 states of phenylnitrene is evaluated by means of ab initio calculations followed by difference‐dedicated configuration interaction (DDCI). This approach is based on effective Hamiltonian theory at a low order of perturbation to select rationally the determinants which contribute to the energy difference. The CI space built on this criterion is then treated variationally. The method allows a considerable reduction of the CI space compared with a complete CAS*SDCI calculation (where CAS stands for complete active space). Depending on the concerned energy difference, different model spaces may be chosen, as illustrated in the 3A2 → 1A2 and the 3A2 → 1A1 transitions in phenylnitrene. Since the CI space may reach considerable dimensions, a direct CI algorithm for selected CI spaces, the SCIEL algorithm, has been used to perform the calculations. The results are in excellent agreement with previous calculations and with available experimental data. © 1996 by John Wiley & Sons, Inc.

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Vectorizable approach to molecular CI problems using determinantal basis

Cited by 100 publications

References 12 publications

The parallel implementation of a full configuration interaction program

The parallel implementation of a full configuration interaction program

The unrestricted natural orbital-restricted active space method: methodology and implementation

Relative stability of the3A2,1A2, and1A1 states of phenylnitrene: A difference-dedicated configuration interaction calculation

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