code: def cyl_to_rect(R,phi,Z):
      
      return (R*sc.cos(phi),R*sc.sin(phi),Z)
docs: NAME:
  
         cyl_to_rect
  
      PURPOSE:
  
         convert from cylindrical to rectangular coordinates
  
      INPUT:
  
         R, phi, Z - cylindrical coordinates
  
      OUTPUT:
  
         X,Y,Z
  
      HISTORY:
  
         2011-02-23 - Written - Bovy (NYU)