Re: Help! License is...

Thanks Anthony.

I see the license requires me to tell you that we are using SimpleORM in the PECAS software for spatial economic modelling and forecasting.  PECAS is used by public agencies for long-range planning of land use and transportation, in particular land use regulations and transportation infrastructure and services provision.

http://www.hbaspecto.com/pecas/

One of the two main PECAS modules is the Space Development (SD) module, which annually considers each bit of land (legal parcel or grid cell) and uses a monte-carlo simulation (ie. random number generator with probability functions) to select developer actions for each bit of land.  Developers are more likely to build specific types of buildings on specific bits of land that 1) are in desireable locations (i.e. can be rented out at a good price), 2) can be constructed cheaply, and 3) are allowed (or not discouraged) by the regulations.

 
SD uses three threads, one thread grabs groups of parcels and puts them in a SimpleORM dataset.  Another thread grabs the "local effect distances" for the group the parcels, which is very time consuming depending on the indexing and clustering in the database.  These local effect distances are things like distance to a major road, distance to a major transit station, distance to the beach, that make a parcel more or less desireable for certain uses.  The third thread processes the parcels, and ends up using the internal simpleorm indices and caches to get the attributes that have already been retrieved into memory by the other two threads.

Since updates and inserts are so slow in most databases (e.g. PostgreSQL), we batch all of them into a separate process.  We process all the parcels and write out the list of changes and inserts to a text file, then apply the full list of changes directly with a database query. (So we rarely use SimpleORM to write data to the database.)

Speed is important, since we are processing millions of parcels in each year of a 30 year simulation run.  Clarity of code is important, partly because speed is important but also because we like to test internal mathematics and logic using the java debugger.

The other PECAS module, "Activity Allocation (AA)", reads everything into memory and then undertakes a computationally intensive search process to solve for the annual spatial economic equilibrium, then writes out the output files. Currently it uses CSV files, rather than a database, since the data flow is so simple.  A big advantage of CSV files is we can version control them using subversion.  But someday we may use a database (and SimpleORM) for AA as well.


--- In [email protected], anthony berglas <anthony@...> wrote:
>
> Hello John,
> 
> I have attached the Copyright notice from the source.
> 
> I'd be interested to know something about the project you use SimpleOrm
> for, and how you use it, and any general feedback.
> 
> Anthony
> 
> On Fri, Dec 21, 2012 at 8:35 AM, <jea@...> wrote:
> 
> > **
> >
> >
> > A client has asked me to specify the libraries I use and their licenses,
> > to ensure that I have permission to release my entire project under Apache
> > V2.
> >
> > On the SimpleORM website is says "Apache style license". I can't find any
> > documentation of the actual license used... If you haven't decided, then
> > Apache V2 would be the most convenient.
> >
> > Thanks for your (hopefully prompt) response!
> >
> > --
> > John
> >
> >  
> >
> 
> 
> 
> -- 
> 
> Dr Anthony Berglas, anthony@...       Mobile: +61 4 4838 8874
> Just because it is possible to push twigs along the ground with ones nose
> does not necessarily mean that that is the best way to collect firewood.
>




------------------------------------

Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/SimpleORM/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/SimpleORM/join
    (Yahoo! ID required)

<*> To change settings via email:
    [email protected] 
    [email protected]

<*> To unsubscribe from this group, send an email to:
    [email protected]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/