SPBSL(3F)							     SPBSL(3F)

NAME    [Toc]    [Back]

     SPBSL   - SPBSL solves the	real symmetric positive	definite band system
     A*X = B using the factors computed	by SPBCO or SPBFA.

SYNOPSYS    [Toc]    [Back]

      SUBROUTINE SPBSL(ABD,LDA,N,M,B)

DESCRIPTION    [Toc]    [Back]

     On	Entry

     ABD REAL(LDA, N)
	the output from	SPBCO or SPBFA.

     LDA INTEGER
	the leading dimension of the array  ABD	.

     N INTEGER
	the order of the matrix	 A .

     M INTEGER
	the number of diagonals	above the main diagonal.

     B REAL(N)
	the right hand side vector.  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 usually
     caused by improper	subroutine arguments.  It will not occur if the
     subroutines are called correctly and  INFO	.EQ. 0 .  To compute
     INVERSE(A)	* C  where  C  is a matrix with	 P  columns
	CALL SPBCO(ABD,LDA,N,RCOND,Z,INFO)
	IF (RCOND is too small .OR. INFO .NE. 0) GO TO ...
	DO 10 J	= 1, P
	CALL SPBSL(ABD,LDA,N,C(1,J)) 10	CONTINUE LINPACK.  This	version	dated
     08/14/78 .	 Cleve Moler, University of New	Mexico,	Argonne	National Lab.
     Subroutines and Functions BLAS SAXPY,SDOT Fortran MIN0


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