# Questions tagged [curve-fitting]

Methods used to fit curves (as in linear or non-linear regression) to data.

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### How do I calculate the error on the extrapolation of a double natural log fit? [duplicate]

I am writing software in Python that tries to fit a data set $t, y$ to the function $y = a \ln(pt) - b \ln(qt)$ and solve for the value of $y$ at $t=30$, denoted $y_0$, and its error $\sigma_{y_0}$. ...
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### How to measure the error on extrapolation from a double log fit? [duplicate]

I am writing residual gas analysis mass spectrometry software in Python. One of the functions of this software is to take the raw mass spec intensity data, $y$, and timestamps $t$, and fit them to the ...
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### Calculating error on a double natural log fit

I am writing residual gas analysis mass spectrometry data reduction software in Python. The evolution of gas intensity $y$ over time $t$ in the mass spec is roughly a double natural logarithmic ...
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### Approximation function for MLP and LSTM

I have total of 6300 samples, 5800 of which are training data, and 500 of which are testing data. We compare the performance of LSTM and multilayer perceptron (MLP) with one hidden layer in terms of ...
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### Finding a function for the number of people on a bus

I've been trying to pin down the function that would describe the number of people on an ideal bus ( # of stops and passengers approaches infinity/ is large enough that the function is continuous), ...
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### What is a good starting model for fitting a rotated sigmoidal curve?

I'm trying to make a model to fit a rotated sigmoidal curve in R but don't know where to start when looking for an appropriate equation for the model. Some example data and the type of fit I'm getting ...
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### How to fit data to a parametric curve/model (x(t), y(t)?

I've got data of x and y pairs and I'd like to fit it to a model that is parametrized as f = (x(t), y(t)). Unfortunately, there is no way for me to analytically solve for t and get a direct ...
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### Help fitting doube-exponential curve to raw mass spec data, time

I am writing mass spec data reduction software in Python for a helium measurement system and could use a hand getting a double-exponential function to fit my data. Basically, the gas in the mass spec ...
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### Graphical analysis of residuals

For an electricity experiment, I have collected data on the charging and discharging of a capacitor. Using the data and scipy.curve_fit, I have fitted the theoretical models. Now, I need to validate ...
1 vote
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### Parameter uncertainty in curve fitting

My real problem has a much more complexity and a different function than following. However, for the sake of simplicity assume I have a data that can be described as a one dimensional Gaussian ...
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### Fitting data to a Malthusian exponential model

I have some data from the exponential phase of yeast growth and I want to fit it to a exponential (Malthusian) growth model or curve, so the growth rate (with its error) and any metric of the goodness ...
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### Fit on original data vs linear fit on transformed data

I asked a question yesterday (Better function to fit log-like data?) and the accepted answer got me thinking. For non-linear data, Is it better/more recommended to asses the goodness of fit on the ...
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### Better function to fit log-like data?

I'm trying to fit a two-parameter function to data that looks like this (black dots, x scale is logarithmic): The best fit I could find is an $arctan$, measured by the MSE. All the seven functions I ...
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1 vote
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### Help identifying a distribution

I'm seeing data whose rank-frequency curve is nearly log linear (b e^(a x)) but where the top few frequencies are higher than expected. The top fits a Bradford distribution well, and the middle is ...
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### How to numerically fit an adaptive composite bezier curve?

Given a set of points $X$ that define a smoothly varying curve $y$ that describe a highly sampled smoothly varying time series I would like to fit some bezier curve sections to the data to effectively ...
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### Estimating a censored distribution curve

I have a sample of only 142 numbers from a distribution of 3852 numbers ranging from 0 to 53, but it is censored below 35 (The values ​​exist, but I don't have access.), so I have only the values in ...
1 vote
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### How to fit data with asymmetric error bars?

General question: How do I fit a model to data when the data points have asymmetric error bars? What is the cost function I use to calculate residuals, and from that, how do I calculate confidence ...
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1 vote
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### How to calculate heteroskedastic standard errors

I'm doing curve fitting, but my error is non-stationary. The variance decreases: I'm looking for a signal in the noise (In this case at x=90, y=50). I'd like to calculate the "standard error&...
1 vote
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### Testing goodness of fit for a Zipf distribution (in Matlab)

I have several ranking distributions and would, for each one, like to fit a [Zipf distribution][1], and estimate the goodness of fit relative to some standard benchmark. With the Matlab code below, I ...
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### Is it possible to use some form of curve identifcation algorithm or model in R to identify a curve based on data from three different treatments?

I was wondering if it is possible to train a model or algorithmn to identify a curve shape based on experimental data. Say we have 3 treatments 0 mM sugar, 1 mM sugar and 10 mM sugar and three ...
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### How to find the linearity of 5 points

I am currently developing a software in C. I have an array (matrix) that contains some coordinate points like this (125 points for now): \begin{bmatrix}x1&x2&x3&x4&x5&...&x125\\...
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