Robin Hankin <r.hankin at noc.soton.ac.uk> writes:
Hi
I am having difficulty with eigen() on R-devel_2006-01-05.tar.gz
Specifically, in R-2.2.0 I get expected behaviour:
eigen(matrix(1:100,10,10),FALSE,TRUE)$values
[1] 5.208398e+02+0.000000e+00i -1.583980e+01+0.000000e+00i
[3] -4.805412e-15+0.000000e+00i 1.347691e-15+4.487511e-15i
[5] 1.347691e-15-4.487511e-15i -4.269863e-16+0.000000e+00i
[7] 1.364748e-16+0.000000e+00i -1.269735e-16+0.000000e+00i
[9] -1.878758e-18+5.031259e-17i -1.878758e-18-5.031259e-17i
The same command gives different results in the development version:
eigen(matrix(1:100,10,10),FALSE,TRUE)$values
[1] 3.903094e-118 -3.903094e-118 -2.610848e-312 -2.995687e-313
-2.748516e-313
[6] -1.073138e-314 -1.061000e-314 -1.060998e-314 4.940656e-324
0.000000e+00
Error: attempt to apply non-function
Strange and semi-random results on SuSE 9.3 as well:
eigen(matrix(1:100,10,10))$values
[1] -5.393552e+194 3.512001e-68 0.000000e+00 0.000000e+00
0.000000e+00
[6] 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00
eigen(matrix(1:100,10,10))$values
[1] 1.526259e-311 -1.041529e-311 1.181720e-313 0.000000e+00
0.000000e+00
[6] 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00
eigen(matrix(1:100,10,10))$values
[1] -9.338774e+93 0.000000e+00 0.000000e+00 0.000000e+00
0.000000e+00
[6] 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00
eigen(matrix(1:100,10,10))$values
[1] 5.4e-311+ 0.0e+00i -2.5e-311+3.7e-311i -2.5e-311-3.7e-311i
[4] 2.5e-312+ 0.0e+00i -2.4e-312+ 0.0e+00i 3.2e-317+ 0.0e+00i
[7] 0.0e+00+ 0.0e+00i 0.0e+00+ 0.0e+00i 0.0e+00+ 0.0e+00i
[10] 0.0e+00+ 0.0e+00i
Mine is closer to Robin's, but not the same (EL4 x86).
> eigen(matrix(1:100,10,10))$values
[1] 5.208398e+02+0.000000e+00i -1.583980e+01+0.000000e+00i
[3] 6.292457e-16+2.785369e-15i 6.292457e-16-2.785369e-15i
[5] -1.055022e-15+0.000000e+00i 3.629676e-16+0.000000e+00i
[7] 1.356222e-16+2.682405e-16i 1.356222e-16-2.682405e-16i
[9] 1.029077e-16+0.000000e+00i -1.269181e-17+0.000000e+00i
But surely, my matrix algebra is a bit rusty, I think this matrix is
solveable analytically? Most of the eigenvalues shown are almost
exactly zero, except the first two, actually, which is about 521
and -16 to the closest integer.
I think the difference between mine and Robin's are rounding errors
(the matrix is simple enough I expect the solution to be simple integers
or easily expressible analystical expressions, so 8 e-values being zero
is fine). Peter's number seems to be all 10 e-values are zero or one
being a huge number! So Peter's is odd... and Peter's machine also
seems
to be of a different archtecture (64-bit machine)?
HTL