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authorstainer_t <thomas.stainer@oecd-nea.org>2025-09-08 13:48:49 +0200
committerstainer_t <thomas.stainer@oecd-nea.org>2025-09-08 13:48:49 +0200
commit7dfcc480ba1e19bd3232349fc733caef94034292 (patch)
tree03ee104eb8846d5cc1a981d267687a729185d3f3 /Dragon/src/SNQU10.f
Initial commit from Polytechnique Montreal
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+*DECK SNQU10
+ SUBROUTINE SNQU10(NLF,JOP,U,W,TPQ,UPQ,VPQ,WPQ)
+*
+*-----------------------------------------------------------------------
+*
+*Purpose:
+* Set the product of Gauss-Legendre and Gauss-Chebyshev quadratures.
+*
+*Copyright:
+* Copyright (C) 2005 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
+* NLF order of the SN approximation (even number).
+*
+*Parameters: output
+* JOP number of base points per axial level in one octant.
+* U base points in $\\xi$ of the axial quadrature. Used with
+* zero-weight points.
+* W weights for the axial quadrature in $\\xi$.
+* TPQ base points in $\\xi$ of the 2D SN quadrature.
+* UPQ base points in $\\mu$ of the 2D SN quadrature.
+* VPQ base points in $\\eta$ of the 2D SN quadrature.
+* WPQ weights of the 2D SN quadrature.
+*
+*-----------------------------------------------------------------------
+*
+*----
+* SUBROUTINE ARGUMENTS
+*----
+ INTEGER NLF,JOP(NLF/2)
+ REAL U(NLF/2),W(NLF/2),TPQ((NLF**2)/4),UPQ((NLF**2)/4),
+ 1 VPQ((NLF**2)/4),WPQ((NLF**2)/4)
+*----
+* LOCAL VARIABLES
+*----
+ PARAMETER(PI=3.141592654,MAXNLF=64)
+ REAL U2(MAXNLF),W2(MAXNLF)
+*----
+* SET THE QUARATURE VALUES.
+*----
+ M2=NLF/2
+ IF(NLF.EQ.2) THEN
+ U(1)=1/SQRT(3.0)
+ W(1)=1.0
+ ELSE
+ IF(NLF.GT.MAXNLF) CALL XABORT('SNQU10: TOO MANY GAUSS POINTS.')
+ CALL ALGPT(NLF,-1.0,1.0,U2,W2)
+ DO 45 M=1,M2
+ U(M)=U2(M2+M)
+ W(M)=W2(M2+M)
+ 45 CONTINUE
+ ENDIF
+ IPQ=0
+ WSUM=0.0
+ DO IP=1,M2
+ JOP(IP)=M2
+ DO IQ=1,M2
+ IPQ=IPQ+1
+ OMEGA=0.5*PI*(1.0-REAL(NLF-2*IQ+1)/REAL(NLF))
+ TPQ(IPQ)=U(IP)
+ UPQ(IPQ)=SQRT(1.0-U(IP)*U(IP))*COS(OMEGA)
+ VPQ(IPQ)=SQRT(1.0-U(IP)*U(IP))*SIN(OMEGA)
+ WPQ(IPQ)=PI*W(IP)/REAL(NLF)
+ WSUM=WSUM+WPQ(IPQ)
+ ENDDO
+ ENDDO
+ RETURN
+ END