The Study Of Parallel Algorithms For Laser Control Of Chemical Reaction Simulations

The development of ultrashort laser pulse allows us to study photochemicalreactions at atomic level. Many chemical reactions that can not be realized bytraditional techniques become possible due to ultrashort laser technology. The mostpopular technique for studying laser induced chemical reactions is Pump-Probespectroscopy. Computer simulation of photochemical reactions is a complementaryapproch to the investigations of the photochemical reactions. Following aphotochemical reaction using computer simulation, researchers can view the chemicalreaction from reactants to products and gain the information about reactionmechanisms.1.A model for realistic parallel simulations of photochemical reactions induced byan ultrashort laser pulses is developed and realized by Fortran90language. Theinterreaction between laser pulses and molecules is unambiguously included in themodel. The technique allows researchers to investigate the influence of the properties oflaser pulses on the outcome of chemical reactions and therefore is a realistic approach tothe study of laser control of chemical reactions. The efficiency of the program isimproved by parallel design, It provides a practical technique for performingphotochemical reactions starting from laser excitation high efficiently. In addition, itprovides many details that could not be observed experimentally.2.An optical algorithm of special matrix multiplication is suggested in semiclassicalmolecular dynamics simulations. Based on the analysis of the serial program, the matrixmultiplication cost most time of the force calculation in semiclassical moleculardynamics simulations. The computation of these gradient matrices and theirmultiplication plays a key role in the Ehrenfest force calculation. Simplifying and thenparallelizing the computation of these nuclear gradients and the matrix multiplicationsnumerically eventually enhance the capacity of Ehrenfest MD simulation.3.A high performance hybrid parallel algorithm for simulating photochemicalreaction is developed by introducing the concept of two layers of parallel capacity. MPIis used in conjunction with OpenMP multithreading to achieve two level parallism of the data and tasks. It is realized based on SMP cluster. It is proved that this method is afeasible parallel algorithm for simulating the photochemical reactions high-efficiently.4.To improve the parallel efficiency on unbalancing system, A dynamic loadbalancing algorithm is designed based on the feedback model. All Tasks areredistributed by load feedback and processing ability forecast. This algorithm adoptedthe dynamic variation of the load. In this study, the algorithm is applied andimplemented in the force calculation of semiclassical molecular dynamic simulations,an optical atomic decomposition is also implemented. Compare with the static loadbalance algorithm, this dynamic load balance algorithm shows better adaptability andscalability.