* Last processed by NICE on 12-Jun-2000 15:53:00
* Customized for :  IEEE, LINUX, UNIX, MOTIF, F77
* nic_dangle.f
*
      SUBROUTINE DANGLE(ALONG,ALAT,A)
************************************************************************
* version 1.0  mpifr cyber edition  22 may 1977.                       *
* see nod 2 manual page m 9.1                                          *
* c.g haslam       mar  1972.                                          *
* this routine recovers the longitude and latitude angles, along       *
* (0 - 360) and alat ( +.- 180) in deg_to_radrees, which correspond to the
* vector a.                                                            *
************************************************************************
*
      REAL*8   A(3)
      REAL*8   ALONG,ALAT
      REAL*8   AA
*
      INCLUDE 'const.inc'
*
      AA     = A(1)*A(1)+A(2)*A(2)
      AA     = DSQRT(AA)
      ALAT   = 90.0D0
      IF (AA.GE.0.000001D0) THEN
         AA = A(3)/AA
         ALAT = DATAN(AA)/DEG_TO_RAD     ! latitude in deg_to_radrees
      ENDIF
*
      IF (A(2).NE.0.D0 .OR. A(1).NE.0.D0) THEN
         ALONG=DATAN2(A(2),A(1))/DEG_TO_RAD    ! longitude in deg_to_radrees
      ELSE
         ALONG = 0.D0
      ENDIF
*
      IF (ALONG.LT.0.0) ALONG=ALONG+360.0D0
      RETURN
      END
*
      SUBROUTINE DCOSIN(ALONG,ALAT,A)    ! direction cosinus
c***********************************************************************
c version 1.0  mpifr cyber edition  22 may 1977.                       *
c see nod 2 manual page m 9.1                                          *
c c.g haslam       mar  1972.                                          *
c this routine computes the vector a for the angles, along and alat,   *
c which should be specified in deg_to_radrees.
c***********************************************************************
*
      REAL*8   A(3)
      REAL*8   ALONG,ALAT
      REAL*8   X,Y,Z
*
      INCLUDE 'const.inc'
*
      X    = DEG_TO_RAD*ALONG            ! x in radians
      Y    = DEG_TO_RAD*ALAT             ! y in radians
      Z    = DCOS(Y)
      A(1) = DCOS(X)*Z
      A(2) = DSIN(X)*Z
      A(3) = DSIN(Y)
      RETURN
      END
*
*
      SUBROUTINE MATMUL(MAT,A,B,N)
c***********************************************************************
c version 1.0  mpifr cyber edition  22 may 1977.  G.Haslam
c version 2.0  iram
c
c this routine provides the transformation of vector a to vector b     *
c using the n dimensional direction cosine array, mat.                *
c***********************************************************************
*
      REAL*8    A(1),B(1),MAT(3,3)
      INTEGER   I,J,N
*
      IF (N.GT.0) THEN
         DO I=1,3
            B(I) = 0.D0
            DO J=1,3
               B(I) = B(I)+MAT(I,J)*A(J)
            ENDDO
         ENDDO
      ELSE
         DO I=1,3
            B(I) = 0.D0
            DO J=1,3
               B(I) = B(I)+MAT(J,I)*A(J)
            ENDDO
         ENDDO
      ENDIF
      RETURN
      END