\stnd cov2cor?
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smedland
Joined: 08/04/2009
Forums
Hi
I'm looking for the OpenMx equivilent to the mx \stnd function. Searching the page the cov2cor() function within mxAlgebra pops up a couple of times but looks to have been discontinued(?) in the more recent releases - any similar function currently availble or implemented in the near future?
thanks
Sarah
the work arround (below) is
the work arround (below) is hanging and taking forever - any ideas on speeding this up?
mxAlgebra( expression= solve(sqrt(I*expCovMZ)) %*% expCovMZ %*% solve(sqrt(I*expCovMZ)), name="expCorMZ" )
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In reply to the work arround (below) is by smedland
We don't perform automatic
We don't perform automatic common subexpression elimination, so the matrix inverse is computed twice. Use the following:
inverse <- mxAlgebra(solve(sqrt(I * expCovMZ)), name = "inverse")expCorMZ <- mxAlgebra(inverse %*% expCovMZ %*% inverse, name = "expCorMZ")
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In reply to We don't perform automatic by mspiegel
%&% there's quadratic
%&% there's quadratic multiplier to help:
mxAlgebra(solve(sqrt(I * expCovMZ)), name = "inverse")
mxAlgebra(inverse %&% expCovMZ , name = "expCorMZ")
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Opened a ticket for cov2cor
Opened a ticket for cov2cor http://openmx.psyc.virginia.edu/issue/2010/06/mxalgebra-wishlist.
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In reply to Opened a ticket for cov2cor by mspiegel
Yes, workshop participants
Yes, workshop participants are struggling in the absence of cov2cor. There's a need for it to be somewhat robust, e.g., if there's a zero or negative value in diagonal element a[i,i] then elements [i,] and [,i] of the result should be NA rather than throwing an error (though a warning may be appropriate).
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