;+
;
; @file_comments
; compute the 3D e3v from e3t and e3t_ps
;
; @categories
; diagnostics
;
; @keyword e1 {default=0}{type=scalar: 0 or 1}
; activate to compute e1v * e3v instead of e3v
; note that of both keywords e1 and e2 are activated we compute e1v * e2v * e3v instead of e3v
;
; @keyword e2 {default=0}{type=scalar: 0 or 1}
; activate to compute e2v * e3v instead of e3v
; note that of both keywords e1 and e2 are activated we compute e1v * e2v * e3v instead of e3v
;
; @returns
; e3v 3D array
;
; @uses
; cm_4mesh.pro
;
; @history
; Sebastien Masson, Jan 2011
;
; @version
; $Id$
;
;-
function e3v_3d, e1 = e1, e2 = e2
;
  compile_opt idl2, strictarrsubs
;
@cm_4mesh
;
  IF keyword_set(key_partialstep) THEN lasty = ( lastyv + 1 ) < ( jpj - 1 ) ELSE lasty = lastyv
  ny = lasty - firstyv + 1
; get e3t 3D
  e3t3d = e3t_3d(fstx = firstxv, lstx = lastxv, fsty = firstyv, lsty = lasty)
;
  IF keyword_set(key_partialstep) THEN BEGIN
; Rebuild the V-point 3D partial steps array from T-point 3D e3t_3D array
    tmp = shift(e3t3d, 0, -1, 0)
    IF ny EQ nyv THEN tmp[*, ny-1, *] = e3t3d[*, ny-1, *]
    e3v3d = [ [ (temporary(e3t3d))[*] ], [ (temporary(tmp))[*] ] ]
    e3v3d = min(temporary(e3v3d), dimension = 2)
    e3v3d = reform(e3v3d, nxv, ny, nzt, /overwrite)
;
    IF ny EQ nyv + 1 THEN e3v3d = (temporary(e3v3d))[*, 0:ny-2, *]
;
  ENDIF ELSE e3v3d = temporary(e3t3d)
;
  CASE 1 OF
    keyword_set(e1) AND keyword_set(e2):arr2d = e1v[firstxv:lastxv, firstyv:lastyv] $
                                              * e2v[firstxv:lastxv, firstyv:lastyv]
    keyword_set(e1)                    :arr2d = e1v[firstxv:lastxv, firstyv:lastyv]
                        keyword_set(e2):arr2d = e2v[firstxv:lastxv, firstyv:lastyv]
    ELSE:
  ENDCASE
;
  IF n_elements(arr2d) NE 0 THEN e3v3d = temporary(e3v3d) * ( arr2d[*] # replicate(1.d, nzt) )
;
  return, e3v3d
END