Francisco Wechsler wrote:
Hello everybody: I am planning to use a few PASCAL programs for certain matrix manipulations. In the past, these subroutines were run in Turbo Pascal 6 or 7, with good numerical accuracy. Because the manual says that gpc doesn't pass the "paranoia" test, I have become a bit wary about running them in gpc. All subroutines are written in ISO PASCAL, and perform things such as: Cholesky decomposition, singular value decomposition, inversion etc. All variables are declared either as INTEGER or REAL. If memory serves me, in TP this means a 10-11 decimal digit mantissa for real numbers. Does anybody have experience in this regard? Am I being too "paranoid"?
I have been using gpc to do calculations where the important step is the diagonalization of some very large matrices. Though for our production problems I currently do this much faster by linking in optimized Lapack/BLAS libraries on an Alpha, running True64, I have no complaints about the accuracy using Intel/Linux systems (using double precision---I can't comment on whether the TP-sized reals are supported).
I'm currently using quite an old version (gpc version 19990118, based on gcc-2.8.1) which works fine for me. Since I have absolutely no interest in language extensions I have not updated since then.
Mike