Re: [UrbanSim-Users] AutoOwnershipChoiceModel

From: Mark Kryvobokov <k_mark_at_ukr.net>
Date: Thu, 15 May 2008 17:26:15 +0300

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Hana,

Thank you. Yes, if the choice set doesn't include 0, it works.

However, we would like to add some location (gridcells) attributes to the agents (households) attributes. In our AutoOwnershipChoiceModel we want to explain the number of cars not only with households attributes, but with e.g. distance to CBD. That's why we want to use household_x_gridcell variables.

Is it possible in principle? We see that the HLCM uses household_x_gridcell variables, but there is location_set = Str('gridcell'), whereas in our case choice_set = ListInt([1,2,3])...

Mark
    
--- Original Message ---
From: Hana Sevcikova <hana_at_cs.washington.edu>
To: Mark Kryvobokov <k_mark_at_ukr.net>
Date: 14 may, 23:31:27
Subject: Re: [UrbanSim-Users] AutoOwnershipChoiceModel
    
    Mark,
    
An interaction variable used in a choice model gives you a 2D array
where one dimension is the number of agents, the other dimension
corresponds to the number choices. I'm not sure, how do you want to use
a household_x_gridcell variable in this context. Do you have a specific
example?
    
Your results of getting singular matrix might be due to the fact, that
you're using a choice set that includes 0. The ChoiceModel doesn't like
that (see http://www.urbansim.org/docs/opus-userguide/node130.html). In
the newest developer version of urbansim you could specify an expression
for choice_attribute_name, e.g. 'carsplus1 = household.cars + 1'. If you
have an older version, you need to add an additional attribute to the
household table that would shift the number of cars by a constant, so
that you don't have a zero there.
    
Hana
    
Mark Kryvobokov wrote:
>
>
> Hello,
>
> We are trying to create the Auto Ownership Choice Model. When we have
> the independent variables from the 'household' dataset only, we obtain a
> singular matrix. It seems that it's not enough to be limited to the
> household attributes. We are trying to use the interaction variables
> from the 'household_x_gridcell' dataset, but we get the error:
>
> "ValueError: different dataset names for variable and dataset or a
> component".
>
> In the auto_ownership_choice_model_configuration_creator we specified:
> agent_set = Str('household') and choice_attribute_name = Str('cars'),
> where 'cars' is an attribute from the 'household' dataset. We also have
> choice_set = ListInt([0,1,2]). So we get the interaction dataset
> 'household_x_choice' and we seem to be limited to the variables that are
> part of that dataset.
>
> Is it possible to use variables from 'household_x_gridcell' in this case
> where there is already an interaction with another dataset which is choice?
>
> Thank you,
>
> Mark
>
>
>
>
>
>
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Received on Thu May 15 2008 - 07:26:18 PDT