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+ SUBROUTINE BRESS2(ITRIAL,XX,DIFF,SIGR,SIGT,B11)
+*
+*-----------------------------------------------------------------------
+*
+*Purpose:
+* Assembly of non-leakage system matrices for the nodal expansion
+* method.
+*
+*Copyright:
+* Copyright (C) 2021 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
+* ITRIAL type of base (=1: polynomial; =2: hyperbolic)
+* XX mesh width.
+* DIFF diffusion coefficient.
+* SIGR macroscopic removal cross section.
+* SIGT macroscopic cross section.
+*
+*Parameters: output
+* B11 nodal matrix.
+*
+*-----------------------------------------------------------------------
+*
+*----
+* SUBROUTINE ARGUMENTS
+*----
+ INTEGER ITRIAL
+ REAL XX,DIFF,SIGR,SIGT,B11(4,4)
+*----
+* WEIGHT RESIDUAL EQUATIONS
+*----
+ B11(:4,:4)=0.0
+ ETA=XX*SQRT(SIGR/DIFF)
+ B11(1,1)=SIGT/12.0
+ B11(2,2)=SIGT/20.0
+ IF(ITRIAL == 1) THEN
+ B11(1,3)=-SIGT/120.0
+ B11(2,4)=-SIGT/700.0
+ ELSE IF(ITRIAL == 2) THEN
+ ALP1=ETA*COSH(ETA/2.0)-2.0*SINH(ETA/2.0)
+ ALP2=((12.0+ETA**2)*SINH(ETA/2.0)-6.0*ETA*COSH(ETA/2.0))/ETA
+ B11(1,3)=SIGT*ALP1/(ETA**2)
+ B11(2,4)=SIGT*ALP2/(ETA**2)
+ ENDIF
+ RETURN
+ END