Characterization of sign patterns that allow diagonalizability has been a long-standing open problem.In this paper,we obtain some sufficient and/or necessary conditions for a sign pattern to allow diagonalizability.Mo...Characterization of sign patterns that allow diagonalizability has been a long-standing open problem.In this paper,we obtain some sufficient and/or necessary conditions for a sign pattern to allow diagonalizability.Moreover,we determine how many entries need to be changed to obtain a matrix B′∈Q(A)with rank MR(A)from a matrix B∈Q(A)with rank mr(A).Finally,we also obtain some results on a sign pattern matrix in Frobenius normal form that allows diagonalizability.展开更多
In this paper,a sequential algorithm computing the all vertex pair distance matrix D and the path matrix Pis given.On a PRAM EREW model with p,1≤p≤n^2,processors,a parallel version of the sequential algorithm is sho...In this paper,a sequential algorithm computing the all vertex pair distance matrix D and the path matrix Pis given.On a PRAM EREW model with p,1≤p≤n^2,processors,a parallel version of the sequential algorithm is shown.This method can also be used to get a parallel algorithm to compute transitive closure arrayof an undirected graph.The time complexify of the parallel algorithm is O(n^3/p).If D,P andare known,it is shown that the problems to find all connected components, to compute the diameter of an undirected graph,to determine the center of a directed graph and to search for a directed cycle with the minimum(maximum)length in a directed graph can all be solved in O(n^2/p^+ logp)time.展开更多
基金Supported by Research Project of Leshan Normal University(Grant No.LZD016)。
文摘Characterization of sign patterns that allow diagonalizability has been a long-standing open problem.In this paper,we obtain some sufficient and/or necessary conditions for a sign pattern to allow diagonalizability.Moreover,we determine how many entries need to be changed to obtain a matrix B′∈Q(A)with rank MR(A)from a matrix B∈Q(A)with rank mr(A).Finally,we also obtain some results on a sign pattern matrix in Frobenius normal form that allows diagonalizability.
基金Research supported by the Science Foundation of Shandong Province.
文摘In this paper,a sequential algorithm computing the all vertex pair distance matrix D and the path matrix Pis given.On a PRAM EREW model with p,1≤p≤n^2,processors,a parallel version of the sequential algorithm is shown.This method can also be used to get a parallel algorithm to compute transitive closure arrayof an undirected graph.The time complexify of the parallel algorithm is O(n^3/p).If D,P andare known,it is shown that the problems to find all connected components, to compute the diameter of an undirected graph,to determine the center of a directed graph and to search for a directed cycle with the minimum(maximum)length in a directed graph can all be solved in O(n^2/p^+ logp)time.
