In this paper we study the effect of block diagonalization of a nearly diagonal matrix by iterating the related Riccati equations. We show that the iteration is fast, if a matrix is diagonally dominant or scaled diagonally dominant and the block partition follows an appropriately defined spectral gap. We also show that both kinds of diagonal dominance are not destroyed after the block diagonali...

A new high-performance general-purpose graphics processing unit (GPGPU) computational fluid dynamics (CFD) library is introduced for use with structured-grid CFD algorithms. A novel set of parallel tridiagonal matrix solvers, implemented in CUDA, is included for use with structured-grid CFD algorithms. The solver library supports both scalar and block-tridiagonal matrices suitable for approxima...

A special structure of a kind of matrices, r−block monomial and r−block diagonal matrices, is introduced. Theirs nonnegative Drazin inverses have been studied. The influence of these matrices on the positiveness of the trajectory of a descriptor system has been analyzed. Key–Words:Drazin inverse, nonnegative matrix, block monomial matrix, descriptor system.

In this paper, necessary and sufficient conditions are given for the k-regularity of block fuzzy matrices in terms of the schur complements of its k-regular diagonal blocks. A formula for k-g-inverse of a block fuzzy matrix is established. A set of conditions for a block matrix to be expressed as the sum of k-regular block matrices is obtained. Mathematics Subject Classification: 15B15; 15A09

gravity drainage is one of the important recovery mechanisms in fractured carbonate and conventional reservoirs. it occurs due to density difference between the gas in fracture and the oil in matrix as well as in conventional tilted reservoirs. oil phase will form films which are produced under gravity forces (film flow). many gas injection experiments have been done on laboratory scales with d...

A PEBAX-nano zeolite X mixed matrix membrane was fabricated and operationally characterized using single gas (CO2) permeation. X-ray diffraction (XRD) analysis was used to study the arrangement of polymer chains of mixed matrix membrane. The membranes were characterized by scanning electron microscopy (SEM) to study cross-sectional morphology. The single gas permeability were carried...

Upper and lower bounds are derived for the absolute values of the eigenvalues of a matrix polynomial (or λ-matrix). The bounds are based on norms of the coefficient matrices and involve the inverses of the leading and trailing coefficient matrices. They generalize various existing bounds for scalar polynomials and single matrices. A variety of tools are used in the derivations, including block ...

We provide a different perspective of the spectral division methods for block generalized Schur decompositions of matrix pairs. The new approach exposes more algebraic structures of the successive matrix pairs in the spectral division iterations and reveals some potential computational difficulties. We present modified algorithms to reduce the arithmetic cost by nearly 50%, remove inconsistency...

The general block distribution of a matrix is a rectilinear partition of the matrix into orthogonal blocks such that the maximum sum of the elements within a single block is minimized. This corresponds to partitioning the matrix onto parallel processors so as to minimize processor load while maintaining regular communication patterns. Applications of the problem include various parallel sparse ...

Composites with negative stiffness inclusions in a viscoelastic matrix are shown to have higher stiffness and mechanical damping tandelta than that of either constituent and exceeding conventional bounds. The causal mechanism is a greater deformation in and near the inclusions than the composite as a whole. Though a block of negative stiffness is unstable, negative stiffness inclusions in a com...