| fe4da5cc |
1 | * |
| 2 | * $Id$ |
| 3 | * |
| 4 | * $Log$ |
| 5 | * Revision 1.1.1.1 1995/10/24 10:21:58 cernlib |
| 6 | * Geant |
| 7 | * |
| 8 | * |
| 9 | #include "geant321/pilot.h" |
| 10 | *CMZ : 3.21/02 29/03/94 15.41.48 by S.Giani |
| 11 | *-- Author : |
| 12 | SUBROUTINE PARTXS(D,LD,E,SIGTOT,EP) |
| 13 | C THIS ROUTINE SAMPLES FROM THE FILE 12 OR 13 PHOTON |
| 14 | C PRODUCTION PARTIAL DISTRIBUTIONS TO OBTAIN THE EXIT |
| 15 | C PHOTON ENERGY FROM A NEUTRON REACTION |
| 16 | #include "geant321/minput.inc" |
| 17 | DIMENSION D(*),LD(*) |
| 18 | SAVE |
| 19 | C INITIALIZE THE VALUES USED IN THE SELECTION PROCESS |
| 20 | C THE VALUE (II) IS A POINTER |
| 21 | ITRY1=0 |
| 22 | 10 R=FLTRNF(0) |
| 23 | SUM=0.0 |
| 24 | NH=0 |
| 25 | NL=0 |
| 26 | II=0 |
| 27 | C SET THE NUMBER OF PARTIAL DISTRIBUTIONS (NK) AND THE NUMBER |
| 28 | C OF POINTS PER PARTIAL DISTRIBUTION (NP) |
| 29 | NK=LD(II+1) |
| 30 | NP=LD(II+2) |
| 31 | II=II+2 |
| 32 | C DETERMINE WHICH POINTS (NL) AND (NH) BOUND THE INCIDENT |
| 33 | C NEUTRON ENERGY |
| 34 | DO 20 N=1,NP |
| 35 | IF(E.LE.D(II+N))GO TO 40 |
| 36 | 20 CONTINUE |
| 37 | C THE INCIDENT NEUTRON ENERGY IS GREATER THAN THE LAST ENERGY |
| 38 | C POINT OF THE PARTIAL DISTRIBUTIONS, THEREFORE USE THE LAST |
| 39 | C ENERGY POINT OF THE PARTIAL DISTRIBUTION TO SAMPLE FROM |
| 40 | NH=NP |
| 41 | II=II+NP |
| 42 | DO 30 K=1,NK |
| 43 | EP=D(II+1) |
| 44 | LP=LD(II+2) |
| 45 | A=D(II+3) |
| 46 | LF=LD(II+4) |
| 47 | IF(LP.EQ.2)EP=EP+(A/(A+1))*E |
| 48 | II=II+4 |
| 49 | SIG=D(II+NH) |
| 50 | SUM=SUM+SIG/SIGTOT |
| 51 | IF(EP.EQ.0.0)GO TO 100 |
| 52 | IF(R.LE.SUM)GO TO 100 |
| 53 | II=II+NP |
| 54 | 30 CONTINUE |
| 55 | GO TO 80 |
| 56 | 40 IF(N.EQ.1)GO TO 60 |
| 57 | C THE INCIDENT NEUTRON ENERGY IS BOUNDED BY THE ENEGY POINTS |
| 58 | C (NL) AND (NH) OF THE PARTIAL DISTRIBUTIONS, THEREFORE USE |
| 59 | C LINEAR INTERPOLATION |
| 60 | NH=N |
| 61 | NL=N-1 |
| 62 | EH=D(II+NH) |
| 63 | EL=D(II+NL) |
| 64 | II=II+NP |
| 65 | DO 50 K=1,NK |
| 66 | EP=D(II+1) |
| 67 | LP=LD(II+2) |
| 68 | A=D(II+3) |
| 69 | LF=LD(II+4) |
| 70 | IF(LP.EQ.2)EP=EP+(A/(A+1))*E |
| 71 | II=II+4 |
| 72 | SIG=D(II+NL)+(E-EL)*(D(II+NH)-D(II+NL))/(EH-EL) |
| 73 | SUM=SUM+SIG/SIGTOT |
| 74 | IF(EP.EQ.0.0)GO TO 100 |
| 75 | IF(R.LE.SUM)GO TO 100 |
| 76 | II=II+NP |
| 77 | 50 CONTINUE |
| 78 | GO TO 80 |
| 79 | C THE INCIDENT NEUTRON ENERGY IS LESS THAN THE FIRST ENERGY |
| 80 | C POINT OF THE PARTIAL DISTRIBUTIONS, THEREFORE USE THE FIRST |
| 81 | C ENERGY POINT OF THE PARTIAL DISTRIBUTION TO SAMPLE FROM |
| 82 | 60 NL=N |
| 83 | II=II+NP |
| 84 | DO 70 K=1,NK |
| 85 | EP=D(II+1) |
| 86 | LP=LD(II+2) |
| 87 | A=D(II+3) |
| 88 | LF=LD(II+4) |
| 89 | IF(LP.EQ.2)EP=EP+(A/(A+1))*E |
| 90 | II=II+4 |
| 91 | SIG=D(II+NL) |
| 92 | SUM=SUM+SIG/SIGTOT |
| 93 | IF(EP.EQ.0.0)GO TO 100 |
| 94 | IF(R.LE.SUM)GO TO 100 |
| 95 | II=II+NP |
| 96 | 70 CONTINUE |
| 97 | C retry with new R if SUM != 0 |
| 98 | 80 IF(SUM.EQ.0.0) GOTO 90 |
| 99 | ITRY1 = ITRY1 + 1 |
| 100 | IF(ITRY1.LE.2) GOTO 10 |
| 101 | C no success set EP = 0 |
| 102 | 90 EP = 0.0 |
| 103 | 100 RETURN |
| 104 | END |
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