Wednesday, November 14, 2007

rescalecov.tcl

Wrote a handy XSPEC Tcl procedure to multiply the covariance matrix used in an MCMC chain proposal distribution by a factor. Use after defining a proposal distribution by eg
 XSPEC12>chain proposal cauchy fit
XSPEC12>source rescalecov.tcl
XSPEC12>rescalecov 0.5
which divides all elements in the covariance matrix by 2.

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