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Re: (Basenote drift) Determinism

On 08/04/2011 06:09 PM, Lee Winter wrote:

On Thu, Aug 4, 2011 at 5:23 AM, N.M. Maclaren<nmm1@xxxxxxxxx>  wrote:



And, lastly, when numeric programmers and their users are given a
choice between deterministic results and much faster execution,
they choose the latter every time.


It appears to me that the above statement is not accurate.  Many
numeric programmers and their users choose faster execution over
deterministic results, but not all.  For example, in simulations it is
very hard to evaluate the fidelity of the results unless they are
deterministic.  So performance gives way to verifiable correctness in
the form of determinism.
Most simulations contain anyway stochastic elements and are therefore not repeatable - except by fixing the seed for debugging purposes. But this only requires the operations to be deterministic on any given environment, and not across platforms. 




Therefore, if there is an underlying reason for 1788 to promote or
require deterministic results then that reason must be stated both
completely and clearly within the standard.
What could such reasons possibly be that the majority of users would adopt determinism if educated? 


Arnold Neumaier