euler_mrot.F

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C   This function computes a 3d rotation matrix.
C   The rotation is about the axis <rx,ry,rz> .
C   The rotation angle [sqrt(rx**2+ry**2+rz**2)] is specified in degrees. 
C   These rotation is counter-clockwise looking from the positive direction.
!||====================================================================
!||    euler_mrot    ../starter/source/model/submodel/euler_mrot.F
!||--- called by ------------------------------------------------------
!||    lectrans      ../starter/source/model/transformation/lectrans.F
!||    lectranssub   ../starter/source/model/submodel/lectranssub.F
!||====================================================================
      SUBROUTINE euler_mrot (RX,RY,RZ,ROT)
C-----------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C-----------------------------------------------
C   D u m m y   A r g u m e n t s
C-----------------------------------------------
C     REAL
      my_real
     .   rx,ry,rz, rot(9)
C-----------------------------------------------
C   L o c a l   V a r i a b l e s
C-----------------------------------------------
C     REAL
      my_real
     .   rx2, ry2, rz2, r2, r, c, cm1, s, sx, sy, sz, cz, 
     .   e11, e22, e33, e12, e13, e31, e32, e21, e23
C=======================================================================
      rx2 = rx*rx                 
      ry2 = ry*ry                 
      rz2 = rz*rz                 
      r2  = max(em20,rx2+ry2+rz2)
      r   = sqrt(r2)        
C
      c = cos(r)                  
      s = sin(r)                
      cm1 = one - c      
C
      rx  = rx / r
      ry  = ry / r
      rz  = rz / r
      rx2 = rx2 / r2                       
      ry2 = ry2 / r2                         
      rz2 = rz2 / r2                        
C
      sx = s*rx                   
      sy = s*ry                   
      sz = s*rz                   
      cz = rz*cm1                 
C-----
      e11 = rx2*cm1 + c           
      e22 = ry2*cm1 + c           
      e33 = rz2*cm1 + c           
C
      e12 = rx*ry*cm1             
      e21 = e12 - sz              
      e12 = e12 + sz              
C
      e13 = rx*cz                 
      e31 = e13 + sy              
      e13 = e13 - sy              
C                                  
      e23 = ry *cz                
      e32 = e23 - sx              
      e23 = e23 + sx              
C-----
      rot(1) = e11              
      rot(2) = e12              
      rot(3) = e13              
      rot(4) = e21              
      rot(5) = e22              
      rot(6) = e23              
      rot(7) = e31              
      rot(8) = e32              
      rot(9) = e33              
C---
      RETURN
      END