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| author | stainer_t <thomas.stainer@oecd-nea.org> | 2025-09-08 13:48:49 +0200 |
|---|---|---|
| committer | stainer_t <thomas.stainer@oecd-nea.org> | 2025-09-08 13:48:49 +0200 |
| commit | 7dfcc480ba1e19bd3232349fc733caef94034292 (patch) | |
| tree | 03ee104eb8846d5cc1a981d267687a729185d3f3 /Dragon/src/B1SOL.f | |
Initial commit from Polytechnique Montreal
Diffstat (limited to 'Dragon/src/B1SOL.f')
| -rw-r--r-- | Dragon/src/B1SOL.f | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/Dragon/src/B1SOL.f b/Dragon/src/B1SOL.f new file mode 100644 index 0000000..00598bd --- /dev/null +++ b/Dragon/src/B1SOL.f @@ -0,0 +1,65 @@ +*DECK B1SOL + SUBROUTINE B1SOL(NGRO,B,IER) +* +*----------------------------------------------------------------------- +* +*Purpose: +* Solution of a system of linear equations that appear in a B1 method. +* Use ALSBD.f for solution in thermal groups. +* +*Copyright: +* Copyright (C) 2002 Ecole Polytechnique de Montreal +* This library is free software; you can redistribute it and/or +* modify it under the terms of the GNU Lesser General Public +* License as published by the Free Software Foundation; either +* version 2.1 of the License, or (at your option) any later version +* +*Author(s): A. Hebert +* +*Parameters: input +* NGRO order of the coefficient matrix. +* +*Parameters: input/output +* B coefficient matrix augmented with the right hand vector on +* input and solution vector, starting at B(1,NGRO+1) at output. +* +*Parameters: output +* IER error flag (execution failure if IER.ne.0). +* +*----------------------------------------------------------------------- +* + IMPLICIT DOUBLE PRECISION (A-H,O-Z) +*---- +* SUBROUTINE ARGUMENTS +*---- + INTEGER NGRO,IER + DOUBLE PRECISION B(NGRO,NGRO+1) +* + IER=0 + NGROIN=0 + DO 30 I=1,NGRO + DO 10 J=I+1,NGRO + IF(B(I,J).NE.0.0D0) GO TO 40 + 10 CONTINUE + NGROIN=I + IF(B(I,I).EQ.0.0D0) THEN + IER=-1 + RETURN + ENDIF + ZGAR=B(I,NGRO+1) + DO 20 J=1,I-1 + ZGAR=ZGAR-B(I,J)*B(J,NGRO+1) + 20 CONTINUE + B(I,NGRO+1)=ZGAR/B(I,I) + 30 CONTINUE + 40 IF(NGROIN.EQ.NGRO) RETURN + DO 60 I=NGROIN+1,NGRO + ZGAR=B(I,NGRO+1) + DO 50 J=1,NGROIN + ZGAR=ZGAR-B(I,J)*B(J,NGRO+1) + 50 CONTINUE + B(I,NGRO+1)=ZGAR + 60 CONTINUE + CALL ALSBD(NGRO-NGROIN,1,B(NGROIN+1,NGROIN+1),IER,NGRO) + RETURN + END |