DGBSL(3F)							     DGBSL(3F)

NAME    [Toc]    [Back]

     DGBSL   - DGBSL solves the	double precision band system A * X = B	or
     TRANS(A) *	X = B using the	factors	computed by DGBCO or DGBFA.

SYNOPSYS    [Toc]    [Back]

      SUBROUTINE DGBSL(ABD,LDA,N,ML,MU,IPVT,B,JOB)

DESCRIPTION    [Toc]    [Back]

     On	Entry

     ABD DOUBLE	PRECISION(LDA, N)
	the output from	DGBCO or DGBFA.

     LDA INTEGER
	the leading dimension of the array  ABD	.

     N INTEGER
	the order of the original matrix.

     ML	INTEGER
	number of diagonals below the main diagonal.

     MU	INTEGER
	number of diagonals above the main diagonal.

     IPVT INTEGER(N)
	the pivot vector from DGBCO or DGBFA.

     B DOUBLE PRECISION(N)
	the right hand side vector.

     JOB INTEGER
	= 0	    to solve  A*X = B ,
	= nonzero   to solve  TRANS(A)*X = B , where
	TRANS(A)  is the transpose.  On	Return

     B the solution vector  X .	Error Condition

     A division	by zero	will occur if the input	factor contains	a zero on the
     diagonal.	Technically this indicates singularity but it is often caused
     by	improper arguments or improper setting of LDA .	 It will not occur if
     the subroutines are called	correctly and if DGBCO has set RCOND .GT. 0.0
     or	DGBFA has set INFO .EQ.	0 .  To	compute	 INVERSE(A) * C	 where	C  is
     a matrix with  P  columns
	CALL DGBCO(ABD,LDA,N,ML,MU,IPVT,RCOND,Z)
	IF (RCOND is too small)	GO TO ...
	DO 10 J	= 1, P
	CALL DGBSL(ABD,LDA,N,ML,MU,IPVT,C(1,J),0) 10 CONTINUE LINPACK.	This
     version dated 08/14/78 .  Cleve Moler, University of New Mexico, Argonne
     National Lab.  Subroutines	and Functions BLAS DAXPY,DDOT Fortran MIN0


									PPPPaaaaggggeeee 1111