Recurrence relations in LabView

[Alzy]

Hi,

I have a problem with a VI that's supposed to estimate coefficients of the linear model by recursive least square method. I tried using For loop with Shift register but the results don't correspond with the ones calculated by Excel.

The formula is the following: a(k)=a(k-1)+mu*e(k-1)*x(k-1)
where mu is a constant, e(k-1) - error.

Can you go over the block diagram and point out mistakes?

Thank you

[szewczak]

can you post the first 20 ints from excel and LV? would be easier to see where problem comes up

[Alzy]

Here we go

[Blokk]

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@Alzy wrote:

Here we go

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Would have been more polite if you attach a txt or excel file with the numbers, so no need to type in the numbers manually 😄

[Alzy]

Deeply sorry for being foolish  . Here is an excel, vi and data.

[szewczak]

looking at your code now, can you run some thing down while I poke around?

• Does the error get worse over the course of the data set (or just stay a little off)
  • Asking because this seems so close that I wonder if this is just the difference of excel and LV floating point rounding design.