Computes the solution to a system of linear equations A * X = B for symmetric matrices.
?sysvroutine computes the solution to a complex system of linear equations A * X = B, where A is an
nsymmetric matrix and X and B are
Aasen's algorithm is used to factor A as A = U * T * U
'U', or A = L * T * L
'L', where U (or L) is a product of permutation and unit upper (lower) triangular matrices, and T is symmetric tri-diagonal. The factored form of A is then used to solve the system of equations A * X= B.
- ='U': The upper triangle of A is stored.
- ='L': The lower triangle of A is stored.
- INTEGERThe number of linear equations; that is, the order of the matrix A.n≥ 0.
- INTEGERThe number of right-hand sides; that is, the number of columns of the matrix B.nrhs≥ 0.
- REALforssysv_aaDOUBLE PRECISIONfordsysv_aaCOMPLEXforcsysv_aaCOMPLEX*16forzsysv_aaArray, dimension (On entry, the symmetric matrix A. Iflda,n).uplo='U', the leadingn-by-nupper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. Ifuplo='L', the leadingn-by-nlower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced.
- INTEGERThe leading dimension of the arrayA.lda≥ max(1,n).
- REALforssysv_aaDOUBLE PRECISIONfordsysv_aaCOMPLEXforcsysv_aaCOMPLEX*16forzsysv_aaArray, dimension (On entry, theldb,nrhs).n-by-nrhsright-hand side matrix B.
- INTEGERThe leading dimension of the arrayB.ldb≥ max(1,n).
- INTEGERThe length of the arraywork.Iflwork=, a workspace query is assumed; the routine calculates only the optimal size of the work array and returns this value as the first entry of the work array, and no error message related to-1lworkis issued by XERBLA.
- REALforssysv_aaDOUBLE PRECISIONfordsysv_aaCOMPLEXforcsysv_aa