Re: fractional time values in an integer Schedule

[Doug Donalson]

There is a way to use fractional times.  It involves using an autodrop
schedule with a concurrent group.
I think I am probably the only Swarmite using this but I like the
"cleanness" of event driven schedules.  If you want to try that approach I
can help you, but not for a week or so.  (One week to my dissertation
defense and part of another to finish my nervous breakdown. [grin])

Cheers,

   D3
----- Original Message -----
From: Andre Costa <address@hidden>
To: <address@hidden>
Sent: Thursday, June 22, 2000 10:39 PM
Subject: fractional time values in an integer Schedule


> Hi,
>
> My question is about how to deal with the limitations of an integer time
> step schedule in Swarm, although I am sure this is a generic simulation
> issue for any discrete-event scheduling simulator.
>
> In my simulation, I have some source nodes in a network (TCP-like) which
> send out discrete packets, and the sources also update their source rates
> x(t) (packets/timestep) according to an adaptive rule
>
> x(t+1) = x(t) +  k*F( )
>
> where k is a "gain" parameter and F( ) is a function which returns an
> integer.
>
> Since x(t) is the number of packets which a source emits in one simulation
> time step, then the this number must be an integer.
>
> However, I need to have a fractional gain parameter, k, which may also
> be interpreted as a "learning rate". Currently, I am constrained to having
> integer values of k, but even k=1 is way too large for my purposes
> (oscillations, etc.)
>
> If x(t) were to be defined as a FLOAT instead of an INT, then what
> scheduling mechanism could deal with say, 2.5 packets per time step,
> whilst still scheduling an integer (by necessity) number of dicrete
> packets per timestep in some reasonable fashion ?
>
> I have thought about defining say, 100 basic Swarm time steps to
> represent 1 simulated time unit, and thus obtaining fractional values
> which resolve to 1/100 of a simulated time unit, but some kind of binning
> would still be required and I wonder if anybody knows of a better
> system....
>
>
> thanks,
> Andre Costa
>
> ---------------------------------------------------------------------
> Andre Costa
> Research Student
>
> **
> Attending Santa Fe Institute Summer School
> during June 00
> email: address@hidden
> **
>
> Teletraffic Research Centre           Telephone: (08) 8303 3237
> Department of Applied Mathematics     Fax:       (08) 8303 4395
> University of Adelaide                Email:address@hidden
> South Australia  5005
> ----------------------------------------------------------------------
>
>
>
>
>
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   esp. using Swarm.  For list administration needs (esp. [un]subscribing),
   please send a message to <address@hidden> with "help" in the
   body of the message.
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