Advice for ALLOCATE available ?

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oOLauraOo
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Advice for ALLOCATE available ?

Post by oOLauraOo »

Dear,

I would like to better understand how the "allocate available" function works, as I cannot manage to do what I expected...

Here is what I wish to represent :
- every year, I have a certain amount of time available for working : 1900 hours/years
- every year, I have tasks to achieve that take me time : works(time) hours/year
- some years, I have more time available than needed to achieve works : 1900hours/years > works(time) hours/year
- some years, I have less time available than needed to achieve works : 1900hours/years < works(time) hours/year

I wish to represent the fact that time, unlike products, cannot be stocked to be used or "shiped" the next years. So I would like the function to ALWAYS consider that the maximum amount of time available is 1900 hours/year, and no more even if I didn't use all of it the year before. But it seems like the function uses previous years unused time to fill the following years demand when works > real available time (1900hours/years).

How can I avoid this ? Perhaps ther is a better allocate function to do this ?

Thank you a lot for your help,

Laura
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Re: Advice for ALLOCATE available ?

Post by Administrator »

I think we'll need to see the model to help. All we can really suggest is looking at the help system, it contains sample models (including one showing the allocation functions).
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
oOLauraOo
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Posts: 41
Joined: Wed Mar 22, 2017 5:05 pm
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Re: Advice for ALLOCATE available ?

Post by oOLauraOo »

I was wrong. The model actually doesn't use previous available hours...
It finally seems like I have a problem with my subscripts, preventing the model to compare the whole demand to the limit of 1900 hours/year.

I mean, the model considers I have 1900 hours/year for each building, and shares it between the associated tasks, instead of sharing the 1900 hours/year available between the different buildings AND their associated tasks.

Would you have any idea about how I could manage this with my subscripts ?
Or shall I use ALLOCATE twice: once to allocate time to buildings, and once again to distribute time to task according to buildings "shipments"/allocation ?

I'll try to isolate this part of the model to show it to you.

Thank you,

Laura
tomfid
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Re: Advice for ALLOCATE available ?

Post by tomfid »

The ALLOC functions only work on one dimension. So, if you are allocating over [Building,Task], it's allocating to tasks for each building separately.

One way to get around this would be to create a single dimension that maps to the 2D [Building,Task] array. It's a bit of a hassle, but easy once you have it set up.
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