C                                                                       00010001
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CTITLESAPOLAR -- POLAR COORDINATE CONVERSION                            00020001
CA    AUTHOR       B. S. BOK                                            00030001
CA    DESIGNER     B. S. BOK                                            00040001
CA    LANGUAGE     FORTRAN                                              00050001
CA    SYSTEM       IBM / CRAY                                           00060001
CA    WRITTEN      AUGUST, 1990                                         00070001
C     REVISED      12-21-91 JJC - MODIFIED TO MEET EDP STANDARDS.
C                                                                       00080001
CA                                                                      00090001
CA    CALL SAPOLAR (RE, NR, XIM, NX, L, AMP, NA, PHZ, NP)
CA                                                                      00110001
CA         INPUT   RE     = REAL PART OF COMPLEX NUMBER             R4  00120001
CA         INPUT   XIM    = IMAGINARY PART OF COMPLEX NUMBER        R4  00130001
CA         INPUT   NR     = COLUMN DIMENSION OF RE                  I4  00140001
CA         INPUT   NX     = COLUMN DIMENSION OF XIM                 I4  00150001
CA         INPUT   L      = NUMBER OF POINTS IN RE AND XIM          I4  00180001
CA         INPUT   NA     = COLUMN DIMENSION OF AMP ARRAY           I4  00190001
CA         INPUT   NP     = COLUMN DIMENSION OF PHZ ARRAY           I4  00190001
CA         OUTPUT  AMP    = AMPLITUDE OF THE POLAR NUMBER           R4  00200001
CA         OUTPUT  PHZ    = PHASE OF THE POLAR NUMBER (RADIAN)      R4
CA
CA    CONVERSION  RE(M) + I*XIM(M) --> AMP(M)*EXP(PHZ(M))
CA
CA    THIS SUBROUTINE PERFORMS POLAR COORDINATE CONVERSION
CA
C
C REMARK ; AMP(1,1) AND PHZ(1,1) MAY BE IN EQUIVALENCE
C          WITH RE(1,1) AND XIM(1,1) IF NR >= NA AND NX >= NP
C
C
      SUBROUTINE SAPOLAR (RE, NR, XIM, NX, L, AMP, NA, PHZ, NP)
C
      IMPLICIT INTEGER (A-Z)
C
      DIMENSION RE(NR,1), XIM(NX,1), PHZ(NP,1), AMP(NA,1)
C
      REAL    AMP
      REAL    ATAN
      REAL    HOLD
      REAL    PHZ
      REAL    PI
      REAL    RE
      REAL    SQRT
      REAL    XIM
C
      PI = 3.14159265
      DO 110 I = 1, L
         RE(1,I) = RE(1,I) + 1.E-30
         HOLD = SQRT(RE(1,I) * RE(1,I) + XIM(1,I) * XIM(1,I))
         IF (XIM(1,I)) 10, 20, 30
   10    IF (RE(1,I)) 40, 50, 60
   20    IF (RE(1,I)) 70, 80, 80
   30    IF (RE(1,I)) 90, 100, 60
   40    PHZ(1,I) = ATAN(XIM(1,I)/RE(1,I)) - PI
         GO TO 110
   50    PHZ(1,I) = -PI/2.0
         GO TO 110
   60    PHZ(1,I) = ATAN(XIM(1,I)/RE(1,I))
         GO TO 110
   70    PHZ(1,I) = - PI
         GO TO 110
   80    PHZ(1,I) = 0.0
         GO TO 110
   90    PHZ(1,I) = ATAN(XIM(1,I)/RE(1,I)) + PI
         GO TO 110
  100    PHZ(1,I) = PI/2.0
  110 AMP(1,I) = HOLD
C
      RETURN
      END