> Hi there,
> I have a question on a naive implementation of a parallel MT that I've
> done using the fortran version of MT19937ar.f posted in Prof.
> Matsumoto's website. (http://www.math.sci.hiroshima...

> Thanks for your reply. Maybe I wasn't clear. I take the first block of
> 624 outputs from the master node to seed the first worker node. I then
> take the second block of 624 outputs from the master node to seed the
> second worker node, and so forth. In this way, every worker node has
> been initialized with a different array of seeds. The master node is
> only used to produce seeds for the worker nodes, it is not used for
> anything else.

> On 2008-04-24 12:22:49 -0300, mjm2...@columbia.edu said:
>

>> Thanks for your reply. Maybe I wasn't clear. I take the first block of
>> 624 outputs from the master node to seed the first worker node. I then
>> take the second block of 624 outputs from the master node to seed the
>> second worker node, and so forth. In this way, every worker node has
>> been initialized with a different array of seeds. The master node is
>> only used to produce seeds for the worker nodes, it is not used for
>> anything else.

>
> Your description still makes it sound like each node will be only
> a delayed version of a lower numbered node.
>
> The internal state of the PRNG is usually called the seed. There may be
> shortcut initial startups, labelled seeds, for those generators that have
> large seeds like MT. Leads to confusion on the meaning of the words when
> the adjectives are dropped. The purpose of a full seed is to pick up again
> EXACTLY where you left off. Having the master step along and give seeds
> to each slave just means that the slaves will exactly follow what the ...

> On Apr 24, 12:01 pm, Gordon Sande worldnet.att.net> wrote:

>> On 2008-04-24 12:22:49 -0300, mjm2...@columbia.edu said:
>>

>>> Thanks for your reply. Maybe I wasn't clear. I take the first block...

> The internal state of the PRNG is usually called the seed. There may be
> shortcut initial startups, labelled seeds, for those generators that have
> large seeds like MT. Leads to confusion on the meaning of the words when
> the adjectives are dropped. The purpose of a full seed is to pick up again
> EXACTLY where you left off. Having the master step along and give seeds
> to each slave just means that the slaves will exactly follow what the
> master would have done. Exact reproducability of PRNGs is important for
> debugging. That is what the saving and restoring of seeds is all about.

> Gordon Sande wrote:
> (snip)
>

>> The internal state of the PRNG is usually called the seed. There may be
>> shortcut initial startups, labelled seeds, for those generators that have
>> large seeds...

> Hi there,
> I have a question on a naive implementation of a parallel MT that I've
> done using the fortran version of MT19937ar.f posted in Prof.
> Matsumoto's website. (http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/
> VERSIONS/FORTRAN/mt19937ar.f)
>
> First, I setup an MT in the master node and seed it with a single
> integer using subroutine init_genrand(seed). I then use the first 624
> outputs from the master node to seed the MT in the first worker node
> using subroutine init_by_array(array_of_seeds,624). I continue in the
> same manner for all subsequent worker nodes, taking the next 624
> outputs from the master node and using them to seed the MT in all
> worker nodes. Once this is done, I have a different MT ready for use
> in all the worker nodes. Do you think this is a good approach? I know
> that the all blocks of 624 seeds used to set up the worker node MTs
> have some correlation (since they are adjacent blocks produced by the
> same MT), but given the equidistribution properties and the gigantic
> period of the algorithm, wouldn't these correlations be insignificant ...

> In the case of the "one word internal state" a case could be made
> that the seed could take states that were not internally possible
> but that the reported internal state would be a seed as well. This
> was for the situation where the 31 bits had to end in "01" (3 mod 8)
> so some of bits in a 32 bit seed could be invalid. Seed is a curious
> uasge at best but seems to be rather well establshed.

> The OP seemed to be saying that each word in the many word internal
> state was a seed so in an attempt to draw his attention to the whole
> thing I used "full seed" on the fly. Better suggestions are welcome. ;-)