1ZGESV(1)              LAPACK driver routine (version 3.2)             ZGESV(1)
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NAME

6       ZGESV  -  computes the solution to a complex system of linear equations
7       A * X = B,
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SYNOPSIS

10       SUBROUTINE ZGESV( N, NRHS, A, LDA, IPIV, B, LDB, INFO )
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12           INTEGER       INFO, LDA, LDB, N, NRHS
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14           INTEGER       IPIV( * )
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16           COMPLEX*16    A( LDA, * ), B( LDB, * )
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PURPOSE

19       ZGESV computes the solution to a complex system of linear equations
20          A * X = B, where A is an N-by-N matrix and X  and  B  are  N-by-NRHS
21       matrices.   The  LU  decomposition with partial pivoting and row inter‐
22       changes is used to factor A as
23          A = P * L * U,
24       where P is a permutation matrix, L is unit lower triangular, and  U  is
25       upper  triangular.   The  factored  form of A is then used to solve the
26       system of equations A * X = B.
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ARGUMENTS

29       N       (input) INTEGER
30               The number of linear equations, i.e., the order of  the  matrix
31               A.  N >= 0.
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33       NRHS    (input) INTEGER
34               The  number of right hand sides, i.e., the number of columns of
35               the matrix B.  NRHS >= 0.
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37       A       (input/output) COMPLEX*16 array, dimension (LDA,N)
38               On entry, the N-by-N coefficient matrix A.  On exit,  the  fac‐
39               tors  L and U from the factorization A = P*L*U; the unit diago‐
40               nal elements of L are not stored.
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42       LDA     (input) INTEGER
43               The leading dimension of the array A.  LDA >= max(1,N).
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45       IPIV    (output) INTEGER array, dimension (N)
46               The pivot indices that define the permutation matrix P;  row  i
47               of the matrix was interchanged with row IPIV(i).
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49       B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS)
50               On entry, the N-by-NRHS matrix of right hand side matrix B.  On
51               exit, if INFO = 0, the N-by-NRHS solution matrix X.
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53       LDB     (input) INTEGER
54               The leading dimension of the array B.  LDB >= max(1,N).
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56       INFO    (output) INTEGER
57               = 0:  successful exit
58               < 0:  if INFO = -i, the i-th argument had an illegal value
59               > 0:  if INFO = i, U(i,i) is exactly zero.   The  factorization
60               has  been  completed,  but the factor U is exactly singular, so
61               the solution could not be computed.
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65 LAPACK driver routine (version 3.N2o)vember 2008                        ZGESV(1)
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