The set of all solutions to the homogeneous system of matrix equations (XA + AX,XB +BX) = (0,0), where (A,B) is a pair of symmetric matrices of the same size, is characterized. In addition, the codimension of the orbit of (A,B) under congruence is calculated. This paper is a natural continuation of the article [A. Dmytryshyn, B. K̊agström, and V.V. Sergeichuk. Skew-symmetric matrix pencils: Codi...

This paper addresses the problem of partitioning the nonzeros of sparse nonsymmetric and nonsquare matrices in order to e ciently compute parallel matrix-vector and matrix-transpose-vector multiplies. Our goal is to balance the work per processor while keeping communications costs low. Although the symmetric partitioning problem has been well-studied, the nonsymmetric and rectangular cases have...

The spectral theorem in linear algebra tells us that every symmetric matrix A (n x n) can be factored as A = PDP , where P is an orthogonal matrix and D is a diagonal matrix comprising of the eigenvalues of A. Such a diagonalization is possible only when A is symmetric. What if A is just a square matrix but not symmetric? We know that every square matrix A (symmetric or not) is diagonalizable a...

In this paper we are interested in the higher-order derivatives of functions of the eigenvalues of symmetric matrices with respect to the matrix argument. We describe the formula for the k-th derivative of such functions in two general cases. The first case concerns the derivatives of the composition of an arbitrary (not necessarily symmetric) k-times differentiable function with the eigenvalue...

We describe a new extension to ScaLAPACK [2] for computing with symmetric (Hermi-tian) matrices stored in a packed form. The new code is built upon the ScaLAPACK routines for full dense storage for a high degree of software reuse. The original ScaLAPACK stores a symmetric matrix as a full matrix but accesses only the lower or upper triangular part. The new code enables more efficient use of mem...

In this review we discuss the relationship between random matrix theories and symmetric spaces. We show that the integration manifolds of random matrix theories, the eigenvalue distribution, and the Dyson and boundary indices characterizing the ensembles are in strict correspondence with symmetric spaces and the intrinsic characteristics of their restricted root lattices. Several important resu...

In this paper, static response and buckling analysis of functionally graded saturated porous beam resting on Winkler elastic foundation is investigated. The beam is modeled using higher-order shear deformation theory in conjunction with Biot constitutive law which has not been surveyed so far. Three different patterns are considered for porosity distribution along the thickness of the beam: 1) ...

The trace of A is Tr(A) ∑di 1 Aii ∑di 1 λi(A). The trace norm of A is ‖A‖∗ ∑di 1 |λi(A)|. A symmetric matrix is positive semide nite (PSD) if all its eigenvalues are nonnegative. Note that for a PSD matrix A, we have Tr(A) ‖A‖∗. We also recall the matrix exponential eA ∑∞k 0 Ak k! which is well-de ned for all real symmetric A and is itself also a real symmetric matrix. If A is symmetric, then e...

We describe a new extension to ScaLAPACK [2] for computing with symmetric (Hermi-tian) matrices stored in a packed form. The new code is built upon the ScaLAPACK routines for full dense storage for a high degree of software reuse. The original ScaLAPACK stores a symmetric matrix as a full matrix but accesses only the lower or upper triangular part. The new code enables more efficient use of mem...

A real symmetric matrix of order n has a full set of orthogonal eigenvectors. The most used approach to compute the spectrum of such matrices reduces first the dense symmetric matrix into a symmetric structured one, i.e., either a tridiagonal matrix [2, 3] or a semiseparable matrix [4]. This step is accomplished in O(n) operations. Once the latter symmetric structured matrix is available, its s...