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vissvess's avatar
vissvess
Helper V
7 years ago
Solved

GCD for multiple values

Hi all,   I recently came accross a requirement to get a calculated column that gets a GCD of multiple values in the related table. Unfortunately, DAX syntax for GCD is for only two values.   My ...
Anonymous's avatar
Anonymous
Not applicable
7 years ago

GCD has the following property:

GCD(GCD(a, b), c) = GCD(a, b, c),

so that means one can calculate it recursively. However, DAX does not support recursive calculations. What remains is the following algorithm.

1. Gather all the numbers for the ID.
2. For each number generate all the divisors by brute force.
3. Intersect the sets of divisors and take the greatest one.

 

However... WHY DON'T YOU DO THIS IN POWER QUERY? Would that not be a lot easier?


Best
Darek

vissvess's avatar
vissvess
Helper V
7 years ago

Hi Anonymous ,

 

This is not that only 3 entries.

 

There may be n entries.

 

So could you suggest me a workaround in detail for me to get the GCD of n numbers in column.

 

Also, if DAX doesnot support recursive calculations, could it be done in M (Power Query)?.

 

Thanks

 

  • Anonymous's avatar
    Anonymous
    Not applicable
    7 years ago
    First of all, the formula I've given you works for ANY number of arguments, not just 3. The extension into n arguments happens through The Induction Principle that you should be familiar with from your mathematics class.

    Second, I'll check if there is a function in Power Query that would do that for you.

    Best
    Darek
    • vissvess's avatar
      vissvess
      Helper V
      7 years ago

      Hi Anonymous ,

       

      It is obvious that the math would work.

       

      I need to clarify my requirement, that there are unknown number of variables to be included.

       

      As far as my search, I have not came accross a M script for GCD directly.

      Yet, there would a workaroud. Please share if you formulate one.

       

      Thanks.