# SLATEC Routines --- BNSLV ---

```*DECK BNSLV
SUBROUTINE BNSLV (W, NROWW, NROW, NBANDL, NBANDU, B)
C***BEGIN PROLOGUE  BNSLV
C***SUBSIDIARY
C***PURPOSE  Subsidiary to BINT4 and BINTK
C***LIBRARY   SLATEC
C***TYPE      SINGLE PRECISION (BNSLV-S, DBNSLV-D)
C***AUTHOR  (UNKNOWN)
C***DESCRIPTION
C
C  BNSLV is the BANSLV routine from
C        * A Practical Guide to Splines *  by C. de Boor
C
C  Companion routine to  BNFAC . It returns the solution  X  of the
C  linear system  A*X = B  in place of  B , given the LU-factorization
C  for  A  in the work array  W from BNFAC.
C
C *****  I N P U T  ******
C  W, NROWW,NROW,NBANDL,NBANDU.....Describe the LU-factorization of a
C        banded matrix  A  of order  NROW  as constructed in  BNFAC .
C        For details, see  BNFAC .
C  B.....Right side of the system to be solved .
C
C *****  O U T P U T  ******
C  B.....Contains the solution  X , of order  NROW .
C
C *****  M E T H O D  ******
C     (With  A = L*U, as stored in  W,) the unit lower triangular system
C  L(U*X) = B  is solved for  Y = U*X, and  Y  stored in  B . Then the
C  upper triangular system  U*X = Y  is solved for  X  . The calcul-
C  ations are so arranged that the innermost loops stay within columns.
C