# Tagged Questions

21 views

### numerical (script) fit of function with 2 arguments

I would like to find the least-square fit for a 1D-function that takes two arguments. m(x,y) = d * (x-x0)^2 / (y-y0)^2 I would like to write a c++ routine to ...
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### Rewriting the matrix equation $AX = YB$ as $Y = CX$?

Is it possible in general, if $A,B,C,X,Y$ are square and of the same dimensions? If so, does it generalize to non-square matrices (using a pseudoinverse)? I'm doing some curve fitting in which I have ...
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### Trigonometric regression

What methods are performed for regression with trigonometric functions? E.g. : Sequence: $$-1, 0, 1, -1, 0, 1, \text{.....}$$ Regression: ...
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### Rate of Decay of the sum of two Exponentials.

I have this data set: ...
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### What is the difference between Curve Fitting and Regression(Machine Learning)?

I know that Machine Learning regression algorithms try to find the function of the data. That is, if we have 1000 data points (x,y), to find a general continuous function that follows the trends of ...
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### Is my form of Lorentz and Gaussian equations suitable for curve fitting?

I am attempting to curve fit gas chromatography spectra. These spectra can be Lorentz or Gaussian or a combination of both. I am using the following code for these equations. ...
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### Determining slope of line relative to a maximum

In the following scientific report (Seismic Q estimation), a mathematical procedure of linear curve-fitting is described in words. The authors state: The stratigraphic effects are minimized by ...
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### Possibility of Unboundedness in Least Squares Minimization

Suppose we have the quadratic minimization problem $$\min_x \frac{1}{2} x^TPx + q^Tx +r$$ We know that when $P$ is symmetric positive semi-definite, but the optimality ...
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### Linear regression where undershooting isn't as bad as overshooting

Given a set of points $(x_i, y_i)$, least-squares linear regression finds the linear function $L$ such that $$\sum \varepsilon(y_i, L(x_i))$$ is minimized, where $\varepsilon(y, y') = (y-y')^2$ is the ...
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### Logistic regression algorithm in Casio and Texas Instruments calculators

When using logistic regression on a Casio or Texas Instruments calculator, the output is of the form $$f(x) = \frac{c}{1+ae^{-bx}}$$ The problem I have (when teaching in a class where both types of ...
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### How does one fit the curve $y = ae^{bx} + c$?

How does one fit the curve $y = ae^{bx} + c$? The method of taking logarithms of both sides does not simplify to allow linear regression. I can take the three equations derived from setting the ...
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### Formula for straight part of a slightly bumpy line

Given a straight line that deviates from the horizontal by at most 15 degrees. On this straight line there are bumps on top at random places on the line. The combined width of the bumps is at most ...
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### Find square root approximation function (tool)

first I have to apologize for any uncorrect naming or categorisation of my question, as I am an electrical engineer rather than a mathematican. I try to find a simple solution for my problem: I have ...
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### Strange behaviour with ode45 in matlab, probably some numerical error.

I'm having a problem with a parameter estimation in a non-linear model. I think the culprit is that ode45 (an ode solver in matlab) is not properly solving my ode. It's the in red highlighted part, ...
I have a sequence of $n$ points $(x_i,y_i)$, for $i=1,\dots,n$. I would like to find the function, of the form $y=V\sin(x+\phi)$, which best fits the points. Which numerical method could I use? I have ...
Possible Duplicate: easy to implement method to fit a power function (regression) I have the following simple function: $h = cV^n$ h and V being the variables and $c$ and $n$ are ...