In this paper, we present an efficient multigrid (MG) algorithm for solving the three-dimensional variable coefficient diffusion equation in cylindrical coordinates. The multigrid V-cycle combines a semi-coarsening in azimuthal direction with the red-black Gauss–Seidel plane (radial-axial plane) relaxation. On each plane relaxation, we further semi-coarsen the axial direction with red-black lin...

in this paper, we apply the  homotopy analysis method (ham) for solving fuzzy  linear systems and present  the necessary and sufficient conditions for the convergence of series solution obtained via the ham. also, we present a new criterion for choosing a proper value of convergence-control parameter $hbar$ when the ham is applied to linear system of equations. comparisons are made between the ...

For iterative solution of saddle point problems, a nonsymmetric preconditioning is studied which, with respect to the upper-left block of the system matrix, can be seen as a variant of SSOR. An idealized situation where the SSOR is taken with respect to the skew-symmetric part plus the diagonal part of the upper-left block is analyzed in detail. Since action of the preconditioner involves solut...

This paper proposes a general execution scheme for paral-lelizing a class of iterative algorithms characterized by strong data dependencies between iterations. This class includes non-simultaneous iterative methods for solving systems of linear equations, such as Gauss-Seidel and SOR, and long-range methods. The paper presents a set of code transformations that make it possible to derive the pa...

Graph-based dependency parsers suffer from the sheer number of higher order edges they need to (a) score and (b) consider during optimization. Here we show that when working with LP relaxations, large fractions of these edges can be pruned before they are fully scored—without any loss of optimality guarantees and, hence, accuracy. This is achieved by iteratively parsing with a subset of highero...

This paper describes an extension to a class of surface reconstruction algorithms based on the minimization of variation of curvature, the so-called curvature consistency framework. It deals explicitly with the problem of localizing surface discontinuities, which was one of the shortcomings of the original work. Inter-pixel interactions during the variational relaxation based smoothing process ...

The internal friction of high-purity NiAl single crystals was investigated utilizing a low-frequency subresonance torsion a p m . Above lOOOK the damping increases strongly up to Q-' =0.3 at 1400K. The activation enthalpy of this viscoelastic relaxation depends on the composition and shows the highest value (2.8eV) for stoichiometric NiAl. The results are discussed in terms of diffusionantrolle...

Internal friction of deformed oriented NaCl single crystals has been measured as a function of flow stress, strain amplitude, frequency, temperature and divalent doping. In pure NaCl af er deformation a maximum of internal friction PI is observed at low temperatures. With increasing 1+ Sr doping a second but much weaker peak P2 appears at higher temperatures. The dependencies of PI on the...

Light scattering in a viscoelastic liquid is studied. The change from liquid to solid-like Brillouin spectra is explained using frequency dependent elasto-optic constants. Within a standard dielectric model microscopic formulas for these generalized frequency dependent constants and the spectra are obtained. The phenomenological pictures of light scattering in an amorphous solid and in a liquid...

This paper is devoted to the analysis of global smooth solutions to the multidimensional isentropic Euler equations with stiff relaxation. We show that the asymptotic behavior of the global smooth solution is governed by the porous media equation as the relaxation time tends to zero. The results are proved by combining some classical energy estimates with the so-called Shizuta-Kawashima condition.