On Thursday, January 26, 2023 at 11:00:02 AM UTC-8, gah4 wrote:
(snip)
Now, the original subject of this thread, is the cost vs. benefit of such optimizations. Not so obvious the benefit, but there is a cost when people try to debug programs where things are optimized away.
[Gee, it's been a while since I thought about SSP. I believe that IBM wrote it largely to give people code that would get reasonable numeric answers
with the 360's funky floating point. Then there were a few odds and ends
like RANDU. They never promised the code would work on anything other
than IBM 360 Fortran. -John]
It seems that there is also SSP for the IBM 1130, which is 16 bit binary,
so probably also a 32 bit two's complement integer.
There is a PL/I SSP, but seems not to have RANDU.
When I was in high school, we had CALL/OS, with PL/I, and
I used the RANDU algorithm, as I didn't have any other one.
As you say, it wasn't promised to work with any other Fortran,
but others did try to stay compatible with IBM.
(But often with non-IBM extensions.)
Fortran systems that I know, are good at ignoring fixed point
overflow, though often trap or count floating point overflow.
[I took a look, RANDU on the 1130 repeated after 2^13 items.
Yow. -John]
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