Hello:
  I am reading Modeller9v8 manual and found in Page 14, 2.2.2, it is said that models could be refined by  VTFM with conjugated gradients(CG) methods. In fact CG is usually applied to correct subtle errors and steepest gradient (SG) is effective for some big erros. I am wondering why not import SG for model refinement?
  In fact, I found that may people would like to do SG before CG when they are doing model refinement.
 
Thank you very much.