Mike Reid wrote:
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).
They're not (not really, anyway). From the manual (`Real Types'):
type name alternative name GNU C equivalent size in bits (typically) ShortReal Single float 32 Real Double double 64 LongReal Extended long double 80
The "alternative names" are like in BP (and are the same types on IA32). BP's `Comp' is an integer type in GPC (64 bits, like in BP).
BP's 6 byte `Real' is not available in GPC. Since it uses software emulation and is therefore slower than any of the other types on a hardware coprocessor (i.e. anything >= 486DX or 386+387), it's not really not recommendable to use it anymore (not even in BP). To work with legacy data files in this format, GPC has conversion routines RealToBPReal and BPRealToReal in the System unit.
Frank