On Wednesday, June 11, 2003, at 02:33 AM, David wrote:
Instead, I'd suggest that Stata develop an internally created and
maintained
property for matrices that indicates whether or not it is symmetric.
I ran into this issue a while back when developing outtable, which
outputs a matrix as a lower triangle iff symmetric. I thought there was
a way to access the internal identifier by which Stata stores only the
lower triangle for a matrix which it considers symmetric (e.g. a
covariance or correlation matrix). After consulting with Stata's
developers, no such luck (there is (or was) no user access to that
flag). They suggested that I use the condition
det(mat - mat') to determine whether the matrix was numerically
symmetric, which is the test employed by outtable.
Kit
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