i'm building an excel model using dynamic arrays which may expand horizontally or vertically depending on the inputs

Example of the array:

I'm trying to calculate the horizontal cumulative sum / running total for each row of an array. I've tried the Scan/Lamda combination explained here: Cumulative Sum Formula using new Excel Dynamic Array Formulas

This leads to a cumulative sum over the complete array, not for each individual row:

Is it possible to achieve a cumulative sum for each row? The solution should look like this:

Thanks

CodePudding user response：

Why not just employ some simple matrix multiplication?

=LET(ζ,A1:D2,ξ,COLUMNS(ζ),MMULT(ζ,N(SEQUENCE(ξ)<=SEQUENCE(,ξ))))