Forum Discussion
help needed with growth estimation
Super Userthat formula looks fishy. sorry, codn't resist. SORRY AGAIN!
weight end = (weight start ^1/3 + Growthfactor * Temperature * 7)/1000) ^1/3)
as written (and ignoring the last bracket) would be:
weight end =
var ws = max[weight start]
var temp=max[Temperature]
var factor = DIVIDE(1,3) -- yes, overkill, i know
return POWER(DIVIDE(POWER(ws, factor) + [Growthfactor]*temp*7),1000),factor)
Haha, i need a glass of water with that one!
I did some small ammendments to your suggestion to accomodate the need for filtering.
I also did a excel withdrawal of the result. However, as you can see it didn't yield exactly the result i was looking for..
So, in essence what i need the [est. size] column to do is to calculate the weight increase of fish at a specific site every week and add it to last week. the starting weight can be found in the column [start size]. This column only holds values when [weeks since sea transfer] = 1. When the [weeks since sea transfer] = 1 a new generation of fish is put to sea and a new cycle is started. Therefore, the column needs to restart everytime [weeks since sea transfer]=1 (which you can see happening in week 25 above).
As there is about 1000 different sites in my dataset i need to be able to filter by [site number].
Hope that clarifies,
Any ideas?
Cheers,
Bump,
Any other suggestions for solving this?
- lbendlin
what is the result you are looking for? Or can you not tell because that would expose the growth factor?
No worries, I can understand it's somewhat hard to understand what to get to 😄
i'll just do as I did in the numbers above and use a random number as the growth factor.
So, whenever [weeks since sea transfer] = 1 the rolling calculation needs to restart. This is when a new generation of fish is put to sea. the value should be 0,115 when [weeks since sea transfer] = 1, this is the starting size of the fish. You should be able to see this clearly in the datadraw i posted earlier.
From there, every week the collumn needs to calulate the result from this equation, and add it to the previous value.
((((previoous week weigth^(1/3)+2.0*('Lakselus per fisk'[seatemperature]*7))/1000))^1/3).As there is about a tousand sites in my sheet I also need to be able to filter by [sitenumber]so with a constant sea temperature of 7 degrees (to simplify) it will be:
(((0,115^(1/3)+2.0*(7*7))/1000))^1/3 =0,0328 +0,115 =0,1478(((0,1478^(1/3)+2.0*(7*7))/1000))^1/3 =0,0328 + 0,1478 = 0,1806
(((0,1806^(1/3)+2.0*(7*7))/1000))^1/3 =0,0328 +0,1806 = 0,213
And so on.. untill [weeks since sea transfer] = 1
Thanks for beeing patient!
Cheers,
- lbendlin
The question here is also - is that a measure (dependent on other filters set by the user) or a calculated column (only computed once)?
In any case the formula will be something like
[starting weight] * PRODUCTX(...)
I need to come back to the original formula
weight end = ((weight start ^1/3 + Growthfactor * Temperature * 7)/1000) ^1/3
If that is correct (I changed some brackets) then it can be written as
weight end = 0.1 * (weight start ^1/3 + Growthfactor * Temperature * 7)^1/3
Right?