Hello,
I have some formulas that should be calculated at the same time to force the output to be 0.
So it should be repeated as long as it’s not 0.
Here’s an exemple:

Month

Quantity

Quantity used

Data

target

Calculated quantity

Number1

Number2

Extra

1

2

2

1

3

quantity+ Data = 2+1

calculated quantity - target = 2+1 - 3

2

3

Calculated quantity month 1 + Quantity = 2+1+3

calculated data to have extra=0

2

quantity+ Data

calculated quantity - target

4

4

calculated quantity - target

5

3

calculated quantity - target

so for missing values in Data columns, the formula is repeated till the extra column = 0
and “quantity calculated” & “quantity used” are updated at the same time.
for the “quantity calculated” i’ve already used a loop but as long as data has missing values it doesnt work.

A part of it is already answered but I don’t know how to calculate multiple formulas at the same time. All the columns should be updated simultaneously.

@HansS Solution helped me calculate the Quantity but but the Data isn’t updated automatically.
As I’ve shown in the exemple, I would like to create a loop that will keep repeating the same formula as long as the extra hasn’t reached 0 and at the same time the quantity should be calculated.
I don’t know if my explanation is clear

If the solution provided by @HansS is doing what you want and now you want to have each month as a column, here is what you need to do:

Use a RowID node and choose the “month” column to replace the row IDs and check the “Remove selected column” option. Then use a Transpose node and it’s done.