DGETRS solves a system of linear equations


    A * X = B  or  A**T * X = B


 with a general N-by-N matrix A using the LU factorization computed


 by DGETRF.

TRANS

          TRANS is CHARACTER*1


          Specifies the form of the system of equations:


          = 'N':  A * X = B  (No transpose)


          = 'T':  A**T* X = B  (Transpose)


          = 'C':  A**T* X = B  (Conjugate transpose = Transpose)

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 DOUBLE PRECISION array, dimension (LDA,N)


          The factors L and U from the factorization A = P*L*U


          as computed by DGETRF.

LDA

          LDA is INTEGER


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

IPIV

          IPIV is INTEGER array, dimension (N)


          The pivot indices from DGETRF; for 1<=i<=N, row i of the


          matrix was interchanged with row IPIV(i).

B

          B is DOUBLE PRECISION 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

Univ. of Colorado Denver

NAG Ltd.

November 2011