generators and endian [from thread on address@hidden

[John W. Eaton]

On 22-Mar-2007, Paul Kienzle wrote:

| 
| On Mar 22, 2007, at 1:55 PM, John W. Eaton wrote:
| 
| > On 22-Mar-2007, David Bateman wrote:
| >
| > | I'd say the option 3) is probably the best, but means the old 
| > generators
| > | won't generator the same sequence as previously on big-endian
| > | machines... Is this an issue?
| >
| > I think it is probably more important for Octave generate the same
| > sequence for a given seed on both big and little endian systems than
| > to preserve some old (and possibly even buggy) behavior.
| 
| This presents an excellent opportunity to toss the old generators,
| at least on big-endian machines.  Any reason to keep them?

Maybe we should keep a "seed" option (in addition to the new "state"
option) for old code?

| How much effort is it worth to guarantee that randn and other
| derived generators produce the same sequence?  The vagaries
| of the optimizer may mean that guard bits allow one threshold
| test to pass on some versions of the compiler but not in others.
| Should we force numbers to memory to clear the guard?

I don't know.  I was assuming it would be a simple change.  If not,
then I don't think it is very important for the old generators.

jwe