SUBROUTINE HYLSET
C     =================
C
C     Initialization procedure for treating the hydrogen line opacity
C
      INCLUDE 'PARAMS.FOR'
      INCLUDE 'SYNTHP.FOR'
      DIMENSION ALB(15)
      DATA ALB /656.28,486.13,434.05,410.17,397.01,
     *          388.91,383.54,379.79,377.06,375.02,
     *          373.44,372.19,371.20,370.39,369.72/
C
C     IHYL=-1  -  hydrogen lines are excluded a priori
C
      IHYL=-1
      if(iath.le.0) return
      IF(FREQ(2).GE.3.28805E15) RETURN
      AL0=2.997925E17/FREQ(1)
      AL1=2.997925E17/FREQ(2)
      IF(AL0.GT.200..AND.AL1.LT.364.6) RETURN
      IF(AL0.GT.560..AND.AL1.LT.580.) RETURN
      IF(AL0.GT.720..AND.AL1.LT.820.3) RETURN
C
C     otherwise, hydrogen lines are included
C
      IHYL=0
      M20=40
      IF(AL1.LT.364.6) THEN
         ILOWH=1
         FRION=3.28805E15
         M10=int(SQRT(3.28805E15/ABS(FRION-FREQ(2))))
         IF(FRION.GT.FREQ(1)) M20=int(SQRT(3.28805E15/(FRION-FREQ(1))))
         IHYL=1
         IF(AL0.GT.123.) IHYL=0
         IF(AL0.GT.104..AND.AL1.LT.120.) IHYL=0
         IF(AL0.GT.98.5.AND.AL1.LT.102.) IHYL=0
         IF(IMODE.EQ.2.OR.IHYDPR.NE.0.OR.GRAV.GE.6.) IHYL=1
       ELSE IF(AL1.LT.820.) THEN
         ILOWH=2
         if(vaclim.lt.3600.) then
         FRION=8.2225E14
         M10=int(SQRT(3.289017E15/ABS(FRION-FREQ(2))))
         else
         FRION=8.22013E14
         M10=int(SQRT(3.28805E15/ABS(FRION-FREQ(2))))
         end if
         IF(FRION.GT.FREQ(1)) M20=int(SQRT(3.289017E15/(FRION-FREQ(1)))) 
         DO 10 I=1,15
            AL=ALB(I)
            IF(AL.LT.AL0-1..OR.AL.GT.AL1+1.) GO TO 10
            IHYL=1
            GO TO 20
   10    CONTINUE
   20    CONTINUE
         IF(IMODE.EQ.2.OR.IHYDPR.NE.0.OR.GRAV.GE.6.) IHYL=1
       ELSE
         ILOWH=3
         IHYL=1
      END IF
c
      ihyl=1
c
      RETURN
      END