Curve fitting gives input, at the output

Hi everybody, i am having a problem at curve fitting function,
i take at output, what i give as input, where do i make mistake?
at example i give 4 values, if i enter 6 values it works, but i need to do it with 4 values.
any ideas?
thanks
Solved!
Go to Solution.
Attachments:
curve fitting.vi ‏16 KB

Your function is a simple quadratic polynomial, so you should use the general polynomial fit function instead. Don't overcomplicate things
LabVIEW Champion . Do more with less code and in less time .

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Attachments:
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Actually I have more than 100 XY data set to test my vi. Some of the data set can be fit flawlessly. And the best fit parameters obtained from my vi are exactly the same as those from other analytical software, like OriginLab. In this case, I know my vi is valid. And in this scenario, I also found 1+b(x-xc)/a is always larger than zero with the best fit parameters (a and b). However, for certain XY data set, the error message will pop up if I use LV built-in vi, but I still can obtain the best fit parameters with OriginLab. And then I realized that error message always pops up as 1+b(x-xc)/a is less than zero, which it means to me that as LV built-in vi handles this type mathematical function, this built-in vi will encounter some difficulties.
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"st" wrote:
> answer me at my mail
give a valid e-mail first, and your name, we don't like to help anonymous
people
> try to send me example.
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> i have transefer function like (1/(s^2+s+5)) and i have a square wave
> input , i want to use this transfer function with this input to see
> the output , how can i do that
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