*DECK SSPSL SUBROUTINE SSPSL (AP, N, KPVT, B) C***BEGIN PROLOGUE SSPSL C***PURPOSE Solve a real symmetric system using the factors obtained C from SSPFA. C***LIBRARY SLATEC (LINPACK) C***CATEGORY D2B1A C***TYPE SINGLE PRECISION (SSPSL-S, DSPSL-D, CHPSL-C, CSPSL-C) C***KEYWORDS LINEAR ALGEBRA, LINPACK, MATRIX, PACKED, SOLVE, SYMMETRIC C***AUTHOR Bunch, J., (UCSD) C***DESCRIPTION C C SSISL solves the real symmetric system C A * X = B C using the factors computed by SSPFA. C C On Entry C C AP REAL(N*(N+1)/2) C the output from SSPFA. C C N INTEGER C the order of the matrix A . C C KPVT INTEGER(N) C the pivot vector from SSPFA. C C B REAL(N) C the right hand side vector. C C On Return C C B the solution vector X . C C Error Condition C C A division by zero may occur if SSPCO has set RCOND .EQ. 0.0 C or SSPFA has set INFO .NE. 0 . C C To compute INVERSE(A) * C where C is a matrix C with P columns C CALL SSPFA(AP,N,KPVT,INFO) C IF (INFO .NE. 0) GO TO ... C DO 10 J = 1, P C CALL SSPSL(AP,N,KPVT,C(1,J)) C 10 CONTINUE C C***REFERENCES J. J. Dongarra, J. R. Bunch, C. B. Moler, and G. W. C Stewart, LINPACK Users' Guide, SIAM, 1979. C***ROUTINES CALLED SAXPY, SDOT C***REVISION HISTORY (YYMMDD) C 780814 DATE WRITTEN C 890531 Changed all specific intrinsics to generic. (WRB) C 890831 Modified array declarations. (WRB) C 891107 Modified routine equivalence list. (WRB) C 891107 REVISION DATE from Version 3.2 C 891214 Prologue converted to Version 4.0 format. (BAB) C 900326 Removed duplicate information from DESCRIPTION section. C (WRB) C 920501 Reformatted the REFERENCES section. (WRB) C***END PROLOGUE SSPSL