code: def set_xticks(start, step, axes="gca"):
      
      if axes=="gca": axes = _pylab.gca()
  
      # first get one of the tick label locations
      yposition = axes.xaxis.get_ticklabels()[0].get_position()[1]
  
      # get the bounds
      xmin, xmax = axes.get_xlim()
  
      # get the starting tick
      nstart = int(_pylab.floor((xmin-start)/step))
      nstop  = int(_pylab.ceil((xmax-start)/step))
      ticks = []
      for n in range(nstart,nstop+1): ticks.append(start+n*step)
  
      axes.set_xticks(ticks)
  
      # set the y-position
      for t in axes.xaxis.get_ticklabels():
          x, y = t.get_position()
          t.set_position((x, yposition))
  
      _pylab.draw()
docs: This will generate a tick array and apply said array to the axis