51 lines
1.0 KiB
Fortran
51 lines
1.0 KiB
Fortran
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c***********************************************************************
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SUBROUTINE LGNDR(PLM,MPLUS,LPLUS,THET)
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c
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c Calculates Legendre polynomials Plm
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c
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c mplus number of m's >0
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c lplus number of l's >0
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c thet angle in degrees
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c***********************************************************************
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c
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IMPLICIT REAL*8(A-H,O-Z)
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DIMENSION PLM(459)
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c
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THETA=THET /57.295779
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Y=COS(THETA)
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Z=SIN(THETA)
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IX=0
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DO 100 M=1,MPLUS
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LX=M-1
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L2=0
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P3=1.0
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FL1=LX
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IF(LX.EQ.0) GO TO 41
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DO 40 LT=1,LX
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FL1=FL1+1.0
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P3=P3*FL1*Z/2.0
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40 CONTINUE
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41 P2=0.0
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FL2=FL1+1.0
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FL3=1.0
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DO 90 LT=1,LPLUS
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IX1=IX+LT
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IF(L2-LX)50,70,60
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50 PLM(IX1)=0.0
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GO TO 75
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60 P3=(FL2*Y*P2-FL1*P1)/FL3
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FL1=FL1+1.0
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FL2=FL2+2.0
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FL3=FL3+1.0
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70 PLM(IX1)=P3
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P1=P2
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P2=P3
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75 L2=L2+1
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90 CONTINUE
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IX=IX+LPLUS
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100 CONTINUE
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RETURN
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END
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