At Tue, 10 Nov 2009 16:25:45 +0100, Mezger Anton-Chr. wrote: > > A small example. I took also the source (I hope the latest one) and a > commented the balancing out which gives then correct results. >
Thanks for the program, I have studied the problem now and can see what is happening. The fit results are inherently different for balanced and unbalanced matrices in the case where singular values are removed. The process of removing singular values is not an invariant operation, since it acts on an individual element of the matrix. This introduces an arbitrariness -- the same difference in the fit results would also occur without automatic balancing if the scale/units of the variables simply happened to be chosen differently (as this is equivalent to the balancing procedure). To avoid confusion, I have added an option to disable the balancing (which will be in the next release). I would be interested to know if the fit results from the balanced case were physically bad in some way or just different from what was expected (the residual in the test case is still small). -- Brian Gough GNU Scientific Library - http://www.gnu.org/software/gsl/ _______________________________________________ Bug-gsl mailing list [email protected] http://lists.gnu.org/mailman/listinfo/bug-gsl
