      SUBROUTINE SIGCL (ETA,SCOU,LMAX,LDIM)
C *** SEE R H LANDAU, PROGRAM LPOTT, 1981
C
C     NB LMAX MUST BE VARIABLE
      IMPLICIT  REAL*8   (A-H,O-Z)
      DIMENSION SCOU(LDIM), FT(5)
      ABETA = ABS(ETA)
      IF (LMAX.GT.LDIM) LMAX = LDIM
      IF (ABETA-1.E-06) 10,10,30
 10   DO 20 I=1,LMAX
         SCOU(I) = 0.E0
 20   CONTINUE
      GO TO 100
 30   C = 1.E0/(ETA*ETA+2601.E0)
      CH = SQRT(C)
      THETA = ATAN(ETA/51.E0)
      DO 40 M=1,5
         FT(M) = SIN(THETA*(2*M-1))
 40   CONTINUE
      SIG2 = 50.5*THETA-ETA*(LOG(CH)+1.)
      SIG2 = SIG2-CH*(FT(1)/12.-C*(FT(2)/360.-C*(FT(3)/1260.-C*(FT(4)/
     11680.-C*FT(5)/1188.))))
      LMAX1 = 50-LMAX
      IF (LMAX1) 70,70,50
 50   DO 60 I=1,LMAX1
         L = 51-I
         SIG2 = SIG2-ATAN(ETA/L)
 60   CONTINUE
 70   LMAX1 = LMAX1+2
      SCOU(LMAX) = SIG2-ATAN(ETA/LMAX)
      IF (LMAX1-50) 80,80,100
 80   DO 90 I=LMAX1,50
         L = 51-I
         SCOU(L) = SCOU(L+1)-ATAN(ETA/L)
 90   CONTINUE
 100  CONTINUE
      RETURN
      END
