hi,
i try to ues "forecast" function in vensim
but i don't know how to set it up ?
i use forecast for set up my target inventory,
and the forecast come from the customer demand
hope some one can give me some suggestion..
pls
thank you ..
how does Forcast function use
how does Forcast function use
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- forecast function.mdl
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forecast
Two examples of the forecast. Your model works correctly, excepted units error.
Zipped with winzip
regards.
JJ
Zipped with winzip
regards.
JJ
- Attachments
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- forecast.zip
- (1.92 KiB) Downloaded 417 times
hi,
thank you for your help!
all my idea is " i need to use customer demand to do the forecasting, then do set up the target inventory".
in your two models, you have added some new variables, in model 2, you have add horizon and average, i think it means i use the last demand to do the forecast.
in model 3, you have added four variables:time set, time,CD at start, and progressing, i don't know what does it mean? and what is customer demand's equation means?
hope can explain more .
thank you .
thank you for your help!
all my idea is " i need to use customer demand to do the forecasting, then do set up the target inventory".
in your two models, you have added some new variables, in model 2, you have add horizon and average, i think it means i use the last demand to do the forecast.
in model 3, you have added four variables:time set, time,CD at start, and progressing, i don't know what does it mean? and what is customer demand's equation means?
hope can explain more .
thank you .
forecast
In the first equation, I replaced the initial values that you put in your model by constants, so as to be able to give the constant a dimension, for instance days.
Vensim supposes if you use a value in an equation that it is dimensionless and may eventually report a dimension error.
So the result of my model was the same, but it had no unit errors.
The other model simulates a simple linear and random increase of the demand and calculates the corresponding forecast value.
You had better start the Vensim user guide and study from the beginning all through, redoing by youself all the models explained. It may take some time, but is the best method for you. I think it is better and easier than studying Sterman's book that is complicated especially if you study it from the beginning up to the end. It is better to study it as a reference book, reading a chapter because it has some concern with your actual problem.
Regards.
JJ
Regards.
JJ
Vensim supposes if you use a value in an equation that it is dimensionless and may eventually report a dimension error.
So the result of my model was the same, but it had no unit errors.
The other model simulates a simple linear and random increase of the demand and calculates the corresponding forecast value.
You had better start the Vensim user guide and study from the beginning all through, redoing by youself all the models explained. It may take some time, but is the best method for you. I think it is better and easier than studying Sterman's book that is complicated especially if you study it from the beginning up to the end. It is better to study it as a reference book, reading a chapter because it has some concern with your actual problem.
Regards.
JJ
Regards.
JJ