On Apr 14, 2009, at 12:26 PM, Luca C. wrote:
Given a seed, rand() will create always the same sequences for that
seed.
The same sequence (singular), yes. Each seed generates only one
sequence.
But if the seeds changes all the time, you'll always get different
sequences, as it's obvious.
Not necessarily. The requirement is that identical seeds produce
identical sequences, but you *can* have different seeds producing the
same sequence. The mapping between seeds and sequences need not be one-
to-one.
You'll get the same sequences only if you pass
the same seed again, otherwise you'll get some other sequences.
Not necessarily. See above.
In practical use of rand() I have never seen what you're saying,
though
it's possible. But that doesn't imply that you'll get every time
the same
number consequentally in a sequence, that's very rare case if you use
different seeds, very rare.
It depends on the quality of the generator. It is very possible that a
given generator would produce the same number N times in a row (for
some N) for some seed. Then, if you use that generator again with the
same seed, you *will* get those same N numbers in a row at the same
point in the generated sequence.
Wagner
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