While using PDL::Fit::LM, which uses PDL::Slatec for matrix inversion, I ran into these numbers,
perldl> p $a =pdl( [qw( 3.5077326e-32 1.1692442e-32 )], [ qw( 1.1692442e-32 3.8974806e-33 ) ]) [ [3.5077326e-32 1.1692442e-32] [1.1692442e-32 3.8974806e-33] ] perldl> p PDL::Slatec::matinv $a [ [-1.6666666e+39 5e+39] [ 5e+39 -1.5e+40] ] But these numbers are different from PDL::MatrixOps' matrix inversion function perldl> p PDL::MatrixOps::inv $a [ [ 2.9544797e+31 -8.8634392e+31] [-3.1090575e+30 2.6590318e+32] ] Any idea why they are different? I'm using 32bit Ubuntu 8.04 with PDL-2.4.4_08. I saw the same thing with 64bit Ubuntu 8.04 and PDL-2.4.4, and in fact, the fit function using Slatec matinv croaks with this error on the 64bit system "uninvertible matrix [ [3.5077326e-32 -0.33333333] [1.1692442e-32 0] ] " I don't even know why the numbers in the error printout is different from $a, because when I check the pdl that was inverted, it was as in $a. Thanks! Maggie _______________________________________________ Perldl mailing list [email protected] http://mailman.jach.hawaii.edu/mailman/listinfo/perldl
