2 Replies Latest reply: Aug 29, 2015 8:11 AM by Mike Fitzgerald RSS

    Σ series solution

      Hi,

       

      I have a partial sum series to resolve.

       

      Y = Σ x/(1+b)^i


      Where the partial sum (Σ) is from i =1 to n. i  varies between 1 to 25 depending on the record. Basically all of the terms of the equation are known except for y.


      What functions could I use to calculate this in a chart, or failing that, in the script?


      Thanks,


      Mike

        • Re: Σ series solution
          Borja Rodriguez

          Could you post a sample dataset?

            • Re: Σ series solution

              Hi Borja,

               

              Thanks for the reply and sorry about my absence.

               

              An example dataset would simply be:

               

              Load * Inline

              [

              Y,b,i

              85000,0.08,12

              125000,0.05,8

              75000,0.02,20

              100000,0.1,10

              ];

               

              Essentially these are parameters for NPV. I am missing the payments and want to extrapolate them using the other terms. Y is the NPV, b is the discount, and i is the life of the loan. I can do this mathematically outside of qlik but cant work out a way to do it in a Qlik load script.

               

              Thanks for the attention to this problem.

               

              Mike