1DGBTRS(1)                LAPACK routine (version 3.1)                DGBTRS(1)
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NAME

6       DGBTRS  -  a system of linear equations  A * X = B or A' * X = B with a
7       general band matrix A using the LU factorization computed by DGBTRF
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SYNOPSIS

10       SUBROUTINE DGBTRS( TRANS, N, KL, KU, NRHS, AB, LDAB, IPIV, B, LDB, INFO
11                          )
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13           CHARACTER      TRANS
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15           INTEGER        INFO, KL, KU, LDAB, LDB, N, NRHS
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17           INTEGER        IPIV( * )
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19           DOUBLE         PRECISION AB( LDAB, * ), B( LDB, * )
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PURPOSE

22       DGBTRS solves a system of linear equations
23          A  * X = B  or  A' * X = B with a general band matrix A using the LU
24       factorization computed by DGBTRF.
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ARGUMENTS

28       TRANS   (input) CHARACTER*1
29               Specifies the form of the system of equations.  = 'N':  A * X =
30               B  (No transpose)
31               = 'T':  A'* X = B  (Transpose)
32               = 'C':  A'* X = B  (Conjugate transpose = Transpose)
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34       N       (input) INTEGER
35               The order of the matrix A.  N >= 0.
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37       KL      (input) INTEGER
38               The number of subdiagonals within the band of A.  KL >= 0.
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40       KU      (input) INTEGER
41               The number of superdiagonals within the band of A.  KU >= 0.
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43       NRHS    (input) INTEGER
44               The  number of right hand sides, i.e., the number of columns of
45               the matrix B.  NRHS >= 0.
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47       AB      (input) DOUBLE PRECISION array, dimension (LDAB,N)
48               Details of the LU factorization of the band matrix A,  as  com‐
49               puted  by  DGBTRF.   U  is  stored  as an upper triangular band
50               matrix with KL+KU superdiagonals in rows 1 to KL+KU+1, and  the
51               multipliers  used  during  the factorization are stored in rows
52               KL+KU+2 to 2*KL+KU+1.
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54       LDAB    (input) INTEGER
55               The leading dimension of the array AB.  LDAB >= 2*KL+KU+1.
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57       IPIV    (input) INTEGER array, dimension (N)
58               The pivot indices; for 1 <= i <= N, row i  of  the  matrix  was
59               interchanged with row IPIV(i).
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61       B       (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
62               On  entry, the right hand side matrix B.  On exit, the solution
63               matrix X.
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65       LDB     (input) INTEGER
66               The leading dimension of the array B.  LDB >= max(1,N).
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68       INFO    (output) INTEGER
69               = 0:  successful exit
70               < 0: if INFO = -i, the i-th argument had an illegal value
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74 LAPACK routine (version 3.1)    November 2006                       DGBTRS(1)
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