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Diffstat (limited to 'Utilib/src/ALGJP.f')
| -rw-r--r-- | Utilib/src/ALGJP.f | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/Utilib/src/ALGJP.f b/Utilib/src/ALGJP.f new file mode 100644 index 0000000..b78db9f --- /dev/null +++ b/Utilib/src/ALGJP.f @@ -0,0 +1,131 @@ +*DECK ALGJP + SUBROUTINE ALGJP(NGPT,ZJKSI,WJKSI) +* +*----------------------------------------------------------------------- +* +*Purpose: +* returns Gauss-Jacobi integration points and weights for integration +* between 0.0 and 1.0 to the order specified +* +*Copyright: +* Copyright (C) 1991 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): R. Roy +* +*Reference: +* integral of X F(X) DX , from 0.0 to 1.0 is given by summ from i=1 to +* NGPT of F(ZJKSI(I))*WJKSI(I) +* the points ZGKSI and weights WJKSI are generated according +* to the technique described in Handbook of mathematical functions +* M. Abramowitz and I. Stegun, Dover Publication Inc. (1972). +* +*Parameters: input +* NGPT number of gauss-jacobi points +* +*Parameters: output +* ZGKSI integration points +* WGKSI integration weights +* +*----------------------------------------------------------------------- +* +*---- +* SUBROUTINE ARGUMENTS +*---- + INTEGER NGPT + REAL ZJKSI(NGPT),WJKSI(NGPT) +*---- +* LOCAL VARIABLES +*---- + PARAMETER ( I1= 1, I2= 2, I3= 4, I4= 7, I5=11, I6=16, + > I7=22, I8=29,IFN=36) + REAL RZKSI(IFN),RWKSI(IFN) +C N=1 + DATA (RZKSI(I),I=I1,I2-1) /0.6666666667/ + DATA (RWKSI(I),I=I1,I2-1) /0.5000000000/ +C N=2 + DATA (RZKSI(I),I=I2,I3-1) /0.3550510257,0.8449489743/ + DATA (RWKSI(I),I=I2,I3-1) /0.1819586183,0.3180413817/ +C N=3 + DATA (RZKSI(I),I=I3,I4-1) /.2123405382,.5905331356,.9114120405/ + DATA (RWKSI(I),I=I3,I4-1) /.0698269799,.2292411064,.2009319137/ +C N=4 + DATA (RZKSI(I),I=I4,I5-1) + > /.1397598643,.4164095676,.7231569864,.9428958039/ + DATA (RWKSI(I),I=I4,I5-1) + > /.0311809710,.1298475476,.2034645680,.1355069134/ +C N=5 + DATA (RZKSI(I),I=I5,I6-1) /.0985350858,.3045357266, + > .5620251898,.8019865821,.9601901429/ + DATA (RWKSI(I),I=I5,I6-1) /.0157479145,.0739088701, + > .1463869871,.1671746381,.0967815902/ +C N=6 + DATA (RZKSI(I),I=I6,I7-1) /.0730543287,.2307661380,.4413284812, + > .6630153097,.8519214003,.9706835728/ + DATA (RWKSI(I),I=I6,I7-1) /.0087383018,.0439551656,.0986611509, + > .1407925538,.1355424972,.0723103307/ +C N=7 + DATA (RZKSI(I),I=I7,I8-1) /.0562625605,.1802406917,.3526247171, + > .5471536263,.7342101772,.8853209468,.9775206136/ + DATA (RWKSI(I),I=I7,I8-1) /.0052143622,.0274083567,.0663846965, + > .1071250657,.1273908973,.1105092582,.0559673634/ +C N=8 + DATA (RZKSI(I),I=I8,IFN) /.0446339553,.1443662570,.2868247571, + > .4548133152,.6280678354,.7856915206,.9086763921,.9822200949/ + DATA (RWKSI(I),I=I8,IFN) /.0032951914,.0178429027,.0454393195, + > .0791995995,.1060473594,.1125057995,.0911190236,.0445508044/ +* + IDEP=0 + IFIN=0 + IF( NGPT.EQ. 1 ) THEN + IDEP=I1 + IFIN=I2-1 + ELSE IF( NGPT.EQ. 2 ) THEN + IDEP=I2 + IFIN=I3-1 + ELSE IF( NGPT.EQ. 3 ) THEN + IDEP=I3 + IFIN=I4-1 + ELSE IF( NGPT.EQ. 4 ) THEN + IDEP=I4 + IFIN=I5-1 + ELSE IF( NGPT.EQ. 5 ) THEN + IDEP=I5 + IFIN=I6-1 + ELSE IF( NGPT.EQ. 6 ) THEN + IDEP=I6 + IFIN=I7-1 + ELSE IF( NGPT.EQ. 7 ) THEN + IDEP=I7 + IFIN=I8-1 + ELSE IF( NGPT.EQ. 8 ) THEN + IDEP=I8 + IFIN=IFN + ELSE + XINF=0.0 + XSUP=1.0 + CALL ALGPT(NGPT,XINF,XSUP,ZJKSI,WJKSI) + ENDIF + IF(NGPT.LE.8) THEN +C------ +C INITIALIZE ZJKSI AND WJKSI FROM DATA BASE +C------ + IUP=1 + DO 100 I=IDEP,IFIN + ZJKSI(IUP)=RZKSI(I) + WJKSI(IUP)=RWKSI(I) + IUP=IUP+1 + 100 CONTINUE + ELSE +C------ +C USE GAUSS-LEGENDRE INTEGRATION POINTS INSTEAD OF GAUSS-JACOBI +C------ + DO 110 I=1,NGPT + WJKSI(I)=WJKSI(I)*ZJKSI(I) + 110 CONTINUE + ENDIF + RETURN + END |