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cgbsv.f(3)				      LAPACK				       cgbsv.f(3)

       cgbsv.f -

       subroutine cgbsv (N, KL, KU, NRHS, AB, LDAB, IPIV, B, LDB, INFO)
	    CGBSV computes the solution to system of linear equations A * X = B for GB matrices
	   (simple driver)

Function/Subroutine Documentation
   subroutine cgbsv (integerN, integerKL, integerKU, integerNRHS, complex, dimension( ldab, *
       )AB, integerLDAB, integer, dimension( * )IPIV, complex, dimension( ldb, * )B, integerLDB,
	CGBSV computes the solution to system of linear equations A * X = B for GB matrices
       (simple driver)


	    CGBSV computes the solution to a complex system of linear equations
	    A * X = B, where A is a band matrix of order N with KL subdiagonals
	    and KU superdiagonals, and X and B are N-by-NRHS matrices.

	    The LU decomposition with partial pivoting and row interchanges is
	    used to factor A as A = L * U, where L is a product of permutation
	    and unit lower triangular matrices with KL subdiagonals, and U is
	    upper triangular with KL+KU superdiagonals.  The factored form of A
	    is then used to solve the system of equations A * X = B.


		     N is INTEGER
		     The number of linear equations, i.e., the order of the
		     matrix A.	N >= 0.


		     KL is INTEGER
		     The number of subdiagonals within the band of A.  KL >= 0.


		     KU is INTEGER
		     The number of superdiagonals within the band of A.  KU >= 0.


		     NRHS is INTEGER
		     The number of right hand sides, i.e., the number of columns
		     of the matrix B.  NRHS >= 0.


		     AB is COMPLEX array, dimension (LDAB,N)
		     On entry, the matrix A in band storage, in rows KL+1 to
		     2*KL+KU+1; rows 1 to KL of the array need not be set.
		     The j-th column of A is stored in the j-th column of the
		     array AB as follows:
		     AB(KL+KU+1+i-j,j) = A(i,j) for max(1,j-KU)<=i<=min(N,j+KL)
		     On exit, details of the factorization: U is stored as an
		     upper triangular band matrix with KL+KU superdiagonals in
		     rows 1 to KL+KU+1, and the multipliers used during the
		     factorization are stored in rows KL+KU+2 to 2*KL+KU+1.
		     See below for further details.


		     LDAB is INTEGER
		     The leading dimension of the array AB.  LDAB >= 2*KL+KU+1.


		     IPIV is INTEGER array, dimension (N)
		     The pivot indices that define the permutation matrix P;
		     row i of the matrix was interchanged with row IPIV(i).


		     B is COMPLEX array, dimension (LDB,NRHS)
		     On entry, the N-by-NRHS right hand side matrix B.
		     On exit, if INFO = 0, the N-by-NRHS solution matrix X.


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


		     INFO is INTEGER
		     = 0:  successful exit
		     < 0:  if INFO = -i, the i-th argument had an illegal value
		     > 0:  if INFO = i, U(i,i) is exactly zero.  The factorization
			   has been completed, but the factor U is exactly
			   singular, and the solution has not been computed.

	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

	   November 2011

       Further Details:

	     The band storage scheme is illustrated by the following example, when
	     M = N = 6, KL = 2, KU = 1:

	     On entry:			     On exit:

		 *    *    *	+    +	  +	  *    *    *	u14  u25  u36
		 *    *    +	+    +	  +	  *    *   u13	u24  u35  u46
		 *   a12  a23  a34  a45  a56	  *   u12  u23	u34  u45  u56
		a11  a22  a33  a44  a55  a66	 u11  u22  u33	u44  u55  u66
		a21  a32  a43  a54  a65   *	 m21  m32  m43	m54  m65   *
		a31  a42  a53  a64   *	  *	 m31  m42  m53	m64   *    *

	     Array elements marked * are not used by the routine; elements marked
	     + need not be set on entry, but are required by the routine to store
	     elements of U because of fill-in resulting from the row interchanges.

       Definition at line 163 of file cgbsv.f.

       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2				 Tue Sep 25 2012			       cgbsv.f(3)
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