Hi,
In simulating the attached model I get weird behaviors, where some 'Initial' variables are simulated incorrectly (and I get warnings for Active/Initial difference). Specifically, check out:
1- 'Sum Initial Buildings' vs. 'Desired Current Buildings' at time zero. The two should be the same but they are not.
2- 'Utility of Alternative Locations' vs. 'Average Realized Utility'. Again, the two should be the same but they are not.
I don't know what is happening, it has been a pain, and it is the first time I am seeing this type of inconsistency. Any insights on what may be going on and how to fix it?
Thanks a lot!
Hazhir
Active vs. Initial Problem/Bug?
Active vs. Initial Problem/Bug?
- Attachments
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- SimpleCity-V05_4.mdl
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Re: Active vs. Initial Problem/Bug?
I'm not back in the office until the new year. Here is some additional debug information in case it helps.
DEBUG:ERROR: Math error (underflow) computing : #Perceived Weighted Product Price>DELAY1I>LV1#[BService].
DEBUG:ERROR: Check causes and uses of #Perceived Weighted Product Price>DELAY1I>LV1#[BService] for division by zero or overflow.
There is an "underflow" error (https://stackoverflow.com/questions/422 ... flow-occur) when calculating "Perceived Weighted Product Price". I'd suggest replicating the DELAY1I macro manually to see if one of the calculations is too small. Once the active/initial problems have been eradicated, I'm sure all will be ok.
DEBUG:ERROR: Math error (underflow) computing : #Perceived Weighted Product Price>DELAY1I>LV1#[BService].
DEBUG:ERROR: Check causes and uses of #Perceived Weighted Product Price>DELAY1I>LV1#[BService] for division by zero or overflow.
There is an "underflow" error (https://stackoverflow.com/questions/422 ... flow-occur) when calculating "Perceived Weighted Product Price". I'd suggest replicating the DELAY1I macro manually to see if one of the calculations is too small. Once the active/initial problems have been eradicated, I'm sure all will be ok.
Advice to posters seeking help (it really helps us to help you)
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391
Units are important!
http://www.bbc.co.uk/news/magazine-27509559
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391
Units are important!
http://www.bbc.co.uk/news/magazine-27509559
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- Senior Member
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- Vensim version: DSS
Re: Active vs. Initial Problem/Bug?
I think the initial value for 'Impact of Affordability on Housing Demand' is causing an issue. I used the values at time=0 as initial, and 'Sum Initial Buildings' and 'Desired Current Buildings' match at the beginning of the simulation, though there's a change in model behavior.
- Attachments
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- SimpleCity-V05_4_AA.mdl
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Re: Active vs. Initial Problem/Bug?
Thanks so much Alireza; that initial value was not needed and removing it indeed solved the problem!