8,604 research outputs found
Excessive Memory Usage of the ELLPACK Sparse Matrix Storage Scheme throughout the Finite Element Computations
Sparse matrices are occasionally encountered during solution of various problems by means of numerical methods, particularly the finite element method. ELLPACK sparse matrix storage scheme, one of the most widely used methods due to its implementation ease, is investigated in this study. The scheme uses excessive memory due to its definition. For the conventional finite element method, where the node elements are used, the excessive memory caused by redundant entries in the ELLPACK sparse matrix storage scheme becomes negligible for large scale problems. On the other hand, our analyses show that the redundancy is still considerable for the occasions where facet or edge elements have to be used
Spinodal Instabilities in Nuclear Matter in a Stochastic Relativistic Mean-Field Approach
Spinodal instabilities and early growth of baryon density fluctuations in
symmetric nuclear matter are investigated in the basis of stochastic extension
of relativistic mean-field approach in the semi-classical approximation.
Calculations are compared with the results of non-relativistic calculations
based on Skyrme-type effective interactions under similar conditions. A
qualitative difference appears in the unstable response of the system: the
system exhibits most unstable behavior at higher baryon densities around
in the relativistic approach while most unstable
behavior occurs at lower baryon densities around in
the non-relativistic calculationsComment: 18 pages, 7 figure
Quenched large deviations for multidimensional random walk in random environment with holding times
We consider a random walk in random environment with random holding times,
that is, the random walk jumping to one of its nearest neighbors with some
transition probability after a random holding time. Both the transition
probabilities and the laws of the holding times are randomly distributed over
the integer lattice. Our main result is a quenched large deviation principle
for the position of the random walk. The rate function is given by the Legendre
transform of the so-called Lyapunov exponents for the Laplace transform of the
first passage time. By using this representation, we derive some asymptotics of
the rate function in some special cases.Comment: This is the corrected version of the paper. 24 page
Dualisation of the D=7 Heterotic String
The dualisation and the first-order formulation of the D=7 abelian Yang-Mills
supergravity which is the low energy effective limit of the D=7 fully Higssed
heterotic string is discussed. The non-linear coset formulation of the scalars
is enlarged to include the entire bosonic sector by introducing dual fields and
by constructing the Lie superalgebra which generates the dualized coset
element.Comment: 20 page
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