在psmatch后，psgraph不能运行，为什么？
. psgraph
no; data are mi set
    Use mi reshape to perform reshape on these data.  mi reshape has the same syntax as reshape.

    Perhaps you did not type reshape.  In that case, the command you typed calls reshape and it is not appropriate for use with mi data.  Use mi extract or mi xeq to select the data
    on which you want to run the command, which is probably m=0.
r(119);