1ZGETRS(1)                LAPACK routine (version 3.1)                ZGETRS(1)
2
3
4

NAME

6       ZGETRS - a system of linear equations  A * X = B, A**T * X = B, or A**H
7       * X = B with a general N-by-N matrix A using the LU factorization  com‐
8       puted by ZGETRF
9

SYNOPSIS

11       SUBROUTINE ZGETRS( TRANS, N, NRHS, A, LDA, IPIV, B, LDB, INFO )
12
13           CHARACTER      TRANS
14
15           INTEGER        INFO, LDA, LDB, N, NRHS
16
17           INTEGER        IPIV( * )
18
19           COMPLEX*16     A( LDA, * ), B( LDB, * )
20

PURPOSE

22       ZGETRS solves a system of linear equations
23          A  *  X  = B,  A**T * X = B,  or  A**H * X = B with a general N-by-N
24       matrix A using the LU factorization computed by ZGETRF.
25
26

ARGUMENTS

28       TRANS   (input) CHARACTER*1
29               Specifies the form of the system of equations:
30               = 'N':  A * X = B     (No transpose)
31               = 'T':  A**T * X = B  (Transpose)
32               = 'C':  A**H * X = B  (Conjugate transpose)
33
34       N       (input) INTEGER
35               The order of the matrix A.  N >= 0.
36
37       NRHS    (input) INTEGER
38               The number of right hand sides, i.e., the number of columns  of
39               the matrix B.  NRHS >= 0.
40
41       A       (input) COMPLEX*16 array, dimension (LDA,N)
42               The  factors  L  and U from the factorization A = P*L*U as com‐
43               puted by ZGETRF.
44
45       LDA     (input) INTEGER
46               The leading dimension of the array A.  LDA >= max(1,N).
47
48       IPIV    (input) INTEGER array, dimension (N)
49               The pivot indices from ZGETRF; for 1<=i<=N, row i of the matrix
50               was interchanged with row IPIV(i).
51
52       B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
53               On  entry, the right hand side matrix B.  On exit, the solution
54               matrix X.
55
56       LDB     (input) INTEGER
57               The leading dimension of the array B.  LDB >= max(1,N).
58
59       INFO    (output) INTEGER
60               = 0:  successful exit
61               < 0:  if INFO = -i, the i-th argument had an illegal value
62
63
64
65 LAPACK routine (version 3.1)    November 2006                       ZGETRS(1)
Impressum