SSYTRS_AA_2STAGE solves a system of linear equations A*X = B with a real


 symmetric matrix A using the factorization A = U*T*U**T or


 A = L*T*L**T computed by SSYTRF_AA_2STAGE.

UPLO

          UPLO is CHARACTER*1


          Specifies whether the details of the factorization are stored


          as an upper or lower triangular matrix.


          = 'U':  Upper triangular, form is A = U*T*U**T;


          = 'L':  Lower triangular, form is A = L*T*L**T.

N

          N is INTEGER


          The order of the matrix A.  N >= 0.

NRHS

          NRHS is INTEGER


          The number of right hand sides, i.e., the number of columns


          of the matrix B.  NRHS >= 0.

A

          A is REAL array, dimension (LDA,N)


          Details of factors computed by SSYTRF_AA_2STAGE.

LDA

          LDA is INTEGER


          The leading dimension of the array A.  LDA >= max(1,N).

TB

          TB is REAL array, dimension (LTB)


          Details of factors computed by SSYTRF_AA_2STAGE.

LTB

          The size of the array TB. LTB >= 4*N.

IPIV

          IPIV is INTEGER array, dimension (N)


          Details of the interchanges as computed by


          SSYTRF_AA_2STAGE.

IPIV2

          IPIV2 is INTEGER array, dimension (N)


          Details of the interchanges as computed by


          SSYTRF_AA_2STAGE.

B

          B is REAL array, dimension (LDB,NRHS)


          On entry, the right hand side matrix B.


          On exit, the solution matrix X.

LDB

          LDB is INTEGER


          The leading dimension of the array B.  LDB >= max(1,N).

INFO

          INFO is INTEGER


          = 0:  successful exit


          < 0:  if INFO = -i, the i-th argument had an illegal value

Univ. of Tennessee

Univ. of California Berkeley

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NAG Ltd.

November 2017