Abstract: Abstract We provide a decomposition that is sufficient in showing when a symmetric tridiagonal matrix A A is completely positive. Our decomposition can be applied to a wide range of matrices. We give alternate proofs for a number of related results found in the literature in a simple, straightforward manner. We show that the cp-rank of any completely positive irreducible tridiagonal doubly stochastic matrix is equal to its rank. We then consider symmetric pentadiagonal matrices, proving some analogous results and providing two different decompositions sufficient for complete positivity. We illustrate our constructions with a number of examples.

Abstract: In this paper we give an algorithm for inverting complex tridiagonal Hermitian matrices with optimal computational efforts. For matrices of a special form and, in particular, for Toeplitz matrices, the derived formulas lead to closed-form expressions for the elements of inverse matrices.

Abstract: There are many practical problems in real life, which are finally attributed to solving large sparse linear equations. In order to solve sparse linear equations in parallel, this paper first analyzes the potential parallel process of solving tridiagonal sparse linear equations by Gaussian elimination method and matrix splitting method, and designs and implements these two parallel algorithms to solve sparse linear equations, Through different process tests and performance analysis, it shows that the Gaussian elimination method has poor time performance, while the matrix splitting method has good efficiency in both space and time.

Abstract: In this paper, we firstly derive a general expression for the entries of the m th ( m ∈ ℕ ) power for two certain types of tridiagonal matrices of arbitrary order. Secondly, we present a method for computing the positive integer powers of the anti-tridiagonal matrix corresponding to these matrices. Also, we give Maple 18 procedures in order to verify our calculations.

Abstract: The extended cyclic reduction algorithm developed by Swarztrauber in 1974 was used to solve the block-tridiagonal linear system. The paper fills in the gap of theoretical results concerning the zeros of matrix polynomial $B_{i}^{(r)}$ with respect to a tridiagonal matrix which are computed by Newton's method in the extended cyclic reduction algorithm. Meanwhile, the forward error analysis of the extended cyclic reduction algorithm for solving the block-tridiagonal system is studied. To achieve the two aims, the critical point is to find out that the zeros of matrix polynomial $B_{i}^{(r)}$ are eigenvalues of a principal submatrix of the coefficient matrix.

Abstract: The principal minors of a tridiagonal matrix satisfy two-term and three-term recurrences [1, 2]. Based on these facts, the current article presents a new efficient and reliable hybrid numerical algorithm for evaluating general n-th order tridiagonal determinants in linear time. The hybrid numerical algorithm avoid all symbolic computations. The algorithm is suited for implementation using computer languages such as FORTRAN, PASCAL, ALGOL, MAPLE, MACSYMA and MATHEMATICA. Some illustrative examples are given. Test results indicate the superiority of the hybrid numerical algorithm.

Abstract: The inverse matrix problem is a hot and active research topic in computational mathematics[1]. It has broad applications in engineering and scientific calculation, and owns a strong background in physics and practical significance[2]. This paper explores the inverse eigenvalue problem of a bordered anti-tridiagonal matrix. It first illustrates the existence and the uniqueness of its solution, the elaborates on the recursive expression of the solution and uses one numerical example to show the effectiveness of the algorithm, and finally concludes that this work is significant and points out suggestions for further study.

Abstract: Abstract This paper aims to show how some standard general results can be used to uncover the spectral theory of tridiagonal and related matrices more elegantly and simply than existing approaches. As a typical example, we apply the theory to the special tridiagonal matrices in recent papers on orthogonal polynomials arising from Jordan blocks. Consequently, we find that the polynomials and spectral theory of the special matrices are expressible in terms of the Chebyshev polynomials of second kind, whose properties yield interesting results. For special cases, we obtain results in terms of the Fibonacci numbers and Legendre polynomials.

Abstract: Abstract In this paper, a fast algorithm for solving the special tridiagonal quasi-Toeplitz system is presented where the bandwidth of a quasi-Toeplitz is larger than the one of Toeplitz. Our algorithm is quite competitive with the classic LU method. Some examples demonstrate the good efficiency and stability of our algorithm.

Abstract: A system of simultaneous algebraic equations with nonzero coefficients only on the main diagonal, the lower diagonal, and the upper diagonal is called a tridiagonal system of equations. Consider a tridiagonal system of N equations with N unknowns, u1, u2, u3,… uN as follows:

Abstract: We present some old and new results in the enumeration of random walks in one dimension, mostly developed in works of enumerative combinatorics. The relation between the trace of the $n$-th power of a tridiagonal matrix and the enumeration of weighted paths of $n$ steps allows an easier combinatorial enumeration of the paths. It also seems promising for the theory of tridiagonal random matrices .

Abstract: A parallel algorithm for solving a series of matrix equations with a constant tridiagonal matrix and different right-hand sides is proposed and studied. The process of solving the problem is represented in two steps. The first preliminary step is fixing some rows of the inverse matrix of SLAEs. The second step consists in calculating solutions for all right-hand sides. For reducing the communication interactions, based on the formulated and proved main parallel sweep theorem, we propose an original algorithm for calculating share components of the solution vector. Theoretical estimates validating the efficiency of the approach for both the common- and distributed-memory supercomputers are obtained. Direct and iterative methods of solving a 2D Poisson equation, which include procedures of tridiagonal matrix inversion, are realized using the mpi technology. Results of computational experiments on a multicomputer demonstrate a high efficiency and scalability of the parallel sweep algorithm.