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help for ^_petrap^ - 28 Jun 2006
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Check to see if model estimation incompatible with postestimation command
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    ^_petrap^ [,^cmd^(string) ^svy^ ^r^obust ^c^luster ^w^eight ^pw^eight
         ^iw^eight ^aw^eight ^force^ ]


Description
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^_petrap^ produces an error message if the previous model estimated uses 
    any of the specified options.  It is intended to use for trapping
    errors in models incompatible with estimation command.

Options
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^cmd()^ name of command that should appear in error message.  if not
    specified, then "program" is used
    
^force^ will ignore conditions, and thus return with no errors

^robust^ exits with error if robust standard errors used in estimated model

^cluster^ exits with error if cluster() specified

^weight^ exits with error if pweight, aweight, or iweight specified

^pweight^ exits with error if pweight specified

^aweight^ exits with error if aweight specified

^iweight^ exits with error if iweight specified

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Authors: J. Scott Long and Jeremy Freese
         www.indiana.edu/~jslsoc/spost.htm
         spostsup@@indiana.edu