Hello.   I'm attempting a large p.c.a. with a high number of variables. pcomp and eigenql keep bugging out when I supply the matrix, but works fine when I supply only a subsection. IDL> .r run_eof_test % Compiled module: $MAIN$. MULTIPLOT: device=X ncol=       2 nrow=       2 charsize=      1.25000 % TRIQL: Too many iterations in tqli. Obviously there is a limit to the size of the number of variables. Any way to over-ride this? Is it dependent on hardware? or the idl routine? Appreciate any help. Thanks. Craig J Wallace