SUBROUTINE CEL2(RES,AK,IER)
	A=1.0
	B=1.-AK**2
      IER=0
      ARI=2.
      GEC=(.5-AK)+.5
      GEC=GEC+GEC*AK
      RES=A
      A1=A+B
      BC=B+B
      IF(GEC) 1,2,6
 1    IER=1
 2    IF(B) 3,8,4
 3    RES=-1.0E30
      RETURN
 4    RES=1.0E30
      RETURN
 5    GEC=GEC*AARI
 6    GEC=SQRT(ABS(GEC))
      GEC=GEC+GEC
      AARI=ARI
      ARI=ARI+GEC
      BC=BC+RES*GEC
      RES=A1
      BC=BC+BC
      A1=BC/ARI+A1
      IF(GEC/AARI-.9999) 5,7,7
 7    RES=A1/ARI
      RES=RES+0.5707963*RES
 8    RETURN
      END