eman - NCMI

Refine OptionsTYPICAL (not required):●shrink= ­ Another option that canproduce dramatic speed improvements.In some cases, this option can actuallyproduce an improvement inclassification accuracy. This optionscales the particles and references downby a factor of n before classification.Since data is often heavily oversampled,and classification is dominated by lowresolution terms, this can be both safe,and actually improve classification by'filtering' out high resolution noise.Generally shrink=2 is safe and effectiveespecially for early refinement. In casesof extreme oversampling, larger valuesmay be ok. This option should not beused for the final rounds of refinementat high resolution.●euler2= ­ This optionshould produce improvements inconvergence and reconstruction quality,but has produced mixed results in thepast. Not recently tested. It adds anadditional step to the refinement processin which class­averages orientations areredetermined by projection­matching.The parameter allows you to decreasethe angular step (ang=) used to generateprojections. ie ­ 2 would produceprojections with angular step of ang/2. Itmay be worth trying, but use it withcaution on new projects. Untested withsome new refine options.