cMEMBER NAME  eul.f  
C         06/20/84   23:45:35     06/20/84   23:43:50     $380300.PLS
C
      BLOCK DATA
      COMMON /CEULER/A(18)
      DATA A/1.0,3*0.0,1.0,3*0.0,1.0,9*0.0/
      END
      SUBROUTINE EULSTT(ARG1,ARG2,ARG3,ARG4,ARG5,ARG6,ARG7)
      COMMON /CEULER/A(9),ALPHA,BETA,GAMMA,X,Y,Z,XP,YP,ZP
      DIMENSION T(1)
      REAL DR/0.01745329252/
      REAL TRIG/3.141592E-6/
      EQUIVALENCE (Z,CSTH),(ZP,CSTHP)
      NARG = 7
      GO TO 10
      ENTRY EULTRN(ARG1,ARG2,ARG3,ARG4)
      NARG = 4
      GO TO 1
      ENTRY EULSET(ARG1,ARG2,ARG3)
      NARG = 3
C SET UP TRANSFORMATION
      GO TO 10
      ENTRY EULRTT (ARG1,ARG2,ARG3,T)
      NARG = 4
   10 IF (ALPHA.EQ.ARG1 .AND. BETA.EQ.ARG2 .AND. GAMMA.EQ.ARG3) GO TO 11
      ALPHA = ARG1
      BETA = ARG2
      GAMMA = ARG3
      CSA = COS(ALPHA*DR)
      IF (ABS(CSA).LT.TRIG) CSA=0
      SNA = SIN(ALPHA*DR)
      IF (ABS(SNA).LT.TRIG) SNA=0
      CSB = COS(BETA*DR)
      IF (ABS(CSB).LT.TRIG) CSB=0
      SNB = SIN(BETA*DR)
      IF (ABS(SNB).LT.TRIG) SNB=0
      CSG = COS(GAMMA*DR)
      IF (ABS(CSG).LT.TRIG) CSG=0
      SNG = SIN(GAMMA*DR)
      IF (ABS(SNG).LT.TRIG) SNG=0
      A(1) = CSG*CSA-CSB*SNA*SNG
      A(2) =-SNG*CSA-CSB*SNA*CSG
      A(3) = SNB*SNA
      A(4) = CSG*SNA+CSB*CSA*SNG
      A(5) =-SNG*SNA+CSB*CSA*CSG
      A(6) =-SNB*CSA
      A(7) = SNG*SNB
      A(8) = CSG*SNB
      A(9) = CSB
   11 IF (NARG.EQ.4) CALL MVC (A,T,36)
      IF (NARG .LT. 7) RETURN
C TRANSFORM SPHERICAL COORDINATES
      THETA = ARG4
      PHI = ARG5
      GO TO 2
    1 THETA = ARG1
      PHI = ARG2
    2 CSTH = COS(THETA*DR)
      IF (ABS(CSTH).LT.TRIG) CSTH=0
      SNTH = SIN(THETA*DR)
      IF (ABS(SNTH).LT.TRIG) SNTH=0
      CSPH = COS(PHI*DR)
      IF (ABS(CSPH).LT.TRIG) CSPH=0
      SNPH = SIN(PHI*DR)
      IF (ABS(SNPH).LT.TRIG) SNPH=0
C UNIT VECTOR IN DIRECTION (THETA,PHI)
      X = CSPH*SNTH
      Y = SNPH*SNTH
      ZP = A(3)*X+A(6)*Y+A(9)*Z
      THETAP = ARCOS(CSTHP)/DR
C 180 >= PHIP > -180
      IF (ABS(CSTHP).LT.1.0) GO TO 3
      PHIP = PHI-ALPHA-GAMMA
      PHIP = AMOD(PHIP+1080,360.0)
      IF (PHIP.GT.180.0) PHIP=PHIP-360.0
      XP = 0
      YP = 0
      GO TO 5
    3 XP = A(1)*X+A(4)*Y+A(7)*Z
      YP = A(2)*X+A(5)*Y+A(8)*Z
      PHIP = ATAN2(YP,XP)/DR
    5 IF (NARG.GT.4) GO TO 4
      ARG3 = THETAP
      ARG4 = PHIP
      RETURN
    4 ARG6 = THETAP
      ARG7 = PHIP
      RETURN
      END