Forum Discussion

siros92's avatar
siros92
Frequent Visitor
6 years ago

help needed with growth estimation

Cheers everyone! As my DAX skills is far from superb i find myself in the need of some help from the community. I'm currently creating growth estimations for Atlantic salmon based on public data....
lbendlin's avatar
lbendlin
Icon for Super User rankSuper User
6 years ago

that 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)

  • siros92's avatar
    siros92
    Frequent Visitor
    6 years ago

    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,

    • siros92's avatar
      siros92
      Frequent Visitor
      6 years ago

      Bump, 

       

      Any other suggestions for solving this? 

    • lbendlin's avatar
      lbendlin
      Icon for Super User rankSuper User
      6 years ago

      what is the result you are looking for? Or can you not tell because that would expose the growth factor?

      • siros92's avatar
        siros92
        Frequent Visitor
        6 years ago

        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,