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Bin aus Magdeburg, Jahrgang 60 und in der Systemadministration beschäftigt.
Crunchen tue ich im Team SETI.Germany

News

About GULP Application
December 24, 2015, 14:30 MSD
New application aimed at testing stability of the GULP code.GULP is a program for performing a variety of types of simulation on materials using boundary conditions of 0-D (molecules and clusters), 1-D (polymers), 2-D (surfaces, slabs and grain boundaries), or 3D (periodic solids). Adaptation of this code for BOINC is a first step to implementation of the computational materials discovery methods to the distributed computing. More specifically, USPEX evolutionary algorithm. This is an algorithm for crystal structure prediction, which is a problem of global optimization, i.e., finding the global minimum of the free energy of the crystal (per mole) with respect to variations of the structure. Successful solution of this problem requires local optimization for each structure generated during prediction. GULP is one of the methods supported by USPEX. That is why we have adapted it for BOINC and providing a test caclucation for it. This is variable cell calculation of the crystal structure of magnesium aluminate (MgAl2O4) with 28 atoms per unit cell at 100 GPa pressure.

Second experimental data set is submitted
October 03, 2014, 20:00 MSD
We submitted a new series of workunits (12289 wus). Each Wu runs local search for 32 times. So in total 131072 local searches are expected. The precision was set to 0.00001. 10 free parameters for Tersoff potential are fitted.

First experimental data set is submitted
October 03, 2014, 20:00 MSD
We submitted a series of workunits (4096 wus). Each Wu runs local search for 32 times. So in total 131072 local searches are expected. The precision was set to 0.00001. 10 free parameters for Tersoff potential are fitted.


New application is deployed!
October 03, 2014, 20:00 MSD
OPTIMA@home now hosts new application aimed at fitting parameters of the Tersoff potential. Molecular dynamics (MD) is often used for modeling various properties of crystals. The essence of this method consists in the numerical solution of the differential equations describing motion of atoms in the crystal lattice to determine the steady state. For molecular-dynamic computations, you must know the potential - a function that determines the interaction energy of atoms in the lattice. Modern potentials used in the simulations contain several parameters. Specific parameter values determine what concrete material is modeled. For example, for silicon, this will be one set, for diamond another etc. The project is aimed at fitting parameter values of the potential in order to achieve known material properties (energy of the lattice cell, the components of the elastic modulus etc.). Then this potential will be used for molecular dynamics simulation. To identify potential parameters we solve the problem of minimizing the variance of the values of the properties obtained by using the potential from known values. This task is to generate a large sequence of initial approximations, from which further methods local search is a (local) minimum. Next, from the obtained values we select tuples with objective values less than the specified precision.


New test set was launched!
July 08, 2014, 20:00 MSD
It is need for the optimization of the solver smallexpx.


...more

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