catch na for comparing current.diff and max.diff

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/bmhyd@34 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
removing sim code, not necessary for users

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/bmhyd@35 edb9625f-4e0d-4859-8d74-9fd3b1da38cb