text:       SUBROUTINE SOLVE1(A1,R1,RP,XI,LAM2,LAM3,LAM4,CONT)
  C
  C     ROUTINE TO SOLVE FOR LAMBDAS AS FNCTS. OF XI
  C
  C
        REAL LAM2,LAM3,LAM4
  C
        IF (RP.EQ.0.0) GO TO 20
  C
        SUM = A1 + XI / RP
        SINSUM = SIN(SUM)
        BB = R1 - RP * (SIN(A1) - SINSUM)
        RT = 0.0E0
        IF( SINSUM .NE. 0.0E0 ) RT = BB / SINSUM
        PSI1 = COS(SUM)
        PSI2 = -SINSUM / RP
  C
  C     CHECK FOR SHELL CAP CASE
        IF ( A1 .NE. 0.0 )  GO TO 40
        LAM2  = 0.0E0
        IF( BB .NE. 0.0E0 ) LAM2  = PSI1 / BB
        LAM3  =  1.0 / RP
        LAM4  = -1.0 / RP**2
        GO TO 50
  C
  C     ALF1 = ALF2
  C
     20 SINA = SIN(A1)
        COSA = COS(A1)
        BB = R1 + XI * COSA
        RT = 0.0E0
        IF( SINA .NE. 0.0E0 ) RT = BB / SINA
        PSI1 = COSA
        PSI2 = 0.0
  C
     40 LAM2 = 0.0E0
        IF( BB .NE. 0.0E0 ) LAM2 = PSI1 / BB
        LAM3 = 0.0E0
        IF( RT .NE. 0.0E0 ) LAM3 = 1.0E0 / RT
        LAM4 = 0.0E0
        IF( BB .NE. 0.0E0 ) LAM4 = PSI2 / BB
  C
     50 CONTINUE
        RETURN
        END
  