Fitting 1-D curve to data points, minimizing pre-defined error/loss function.
From wiki:
Curve fitting is the process of constructing a curve, or mathematical function, that has the best fit to a series of data points.
Questions tagged [curve-fitting]
3428 questions
41
votes
4 answers
Fitting a closed curve to a set of points
I have a set of points pts which form a loop and it looks like this:
This is somewhat similar to 31243002, but instead of putting points in between pairs of points, I would like to fit a smooth curve through the points (coordinates are given at the…
Mahdi
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38
votes
2 answers
Fit sigmoid function ("S" shape curve) to data using Python
I'm trying to fit a sigmoid function to some data I have but I keep getting:ValueError: Unable to determine number of fit parameters.
My data looks like this:
My code is:
from scipy.optimize import curve_fit
def sigmoid(x):
return…
user88484
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35
votes
5 answers
How can I fit a Bézier curve to a set of data?
I have a set of data points (which I can thin out) that I need to fit with a Bézier curve. I need speed over accuracy, but the fit should be decent enough to be recognizable. I'm also looking for an algorithm I can use that doesn't make much use of…
user791684
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33
votes
2 answers
Exponential curve fitting in SciPy
I have two NumPy arrays x and y. When I try to fit my data using exponential function and curve_fit (SciPy) with this simple code
#!/usr/bin/env python
from pylab import *
from scipy.optimize import curve_fit
x = np.array([399.75, 989.25, 1578.75,…
drastega
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32
votes
2 answers
What's the error of numpy.polyfit?
I want to use numpy.polyfit for physical calculations, therefore I need the magnitude of the error.
varantir
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31
votes
7 answers
Curve fitting unsorted points on a plane
Question: How do you fit a curve to points on a plane if they aren't single valued?
For the example shown, how would one fit a curve (like the black one) to the noisy blue data? It's similar to spline smoothing, but I don't know the order of the…
tkw954
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30
votes
2 answers
Fitting a line in 3D
Are there any algorithms that will return the equation of a straight line from a set of 3D data points? I can find plenty of sources which will give the equation of a line from 2D data sets, but none in 3D.
Thanks.
Mike
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28
votes
4 answers
Fit a gaussian function
I have a histogram (see below) and I am trying to find the mean and standard deviation along with code which fits a curve to my histogram. I think there is something in SciPy or matplotlib that can help, but every example I've tried doesn't work. …
user1496646
26
votes
6 answers
Goodness of fit functions in R
What functions do you use in R to fit a curve to your data and test how well that curve fits? What results are considered good?
medriscoll
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25
votes
3 answers
Why does scipy.optimize.curve_fit not fit to the data?
I've been trying to fit an exponential to some data for a while using scipy.optimize.curve_fit but i'm having real difficulty. I really can't see any reason why this wouldn't work but it just produces a strait line, no idea why!
Any help would be…
user1696811
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24
votes
7 answers
Nonlinear regression with python - what's a simple method to fit this data better?
I have some data that I want to fit so I can make some estimations for the value of a physical parameter given a certain temperature.
I used numpy.polyfit for a quadratic model, but the fit isn't quite as nice as I'd like it to be and I don't have…
Jinx
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24
votes
2 answers
How can I fit a gaussian curve in python?
I'm given an array and when I plot it I get a gaussian shape with some noise. I want to fit the gaussian. This is what I already have but when I plot this I do not get a fitted gaussian, instead I just get a straight line. I've tried this many…
P. Kaur
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24
votes
1 answer
Curve Fitting to a time series in the format 'datetime'?
Here is my problem: polyfit does not take datetime values, so that I converted datetime with mktime producing the polynomial fit works
z4 = polyfit(d, y, 3)
p4 = poly1d(z4)
For the plot however, I would like the datetime description on the axis…
Corins
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24
votes
5 answers
How do I put a constraint on SciPy curve fit?
I'm trying to fit the distribution of some experimental values with a custom probability density function. Obviously, the integral of the resulting function should always be equal to 1, but the results of simple scipy.optimize.curve_fit(function,…
Axon
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23
votes
1 answer
Why isn't `curve_fit` able to estimate the covariance of the parameter if the parameter fits exactly?
I don't understand curve_fit isn't able to estimate the covariance of the parameter, thus raising the OptimizeWarning below. The following MCVE explains my problem:
MCVE python snippet
from scipy.optimize import curve_fit
func = lambda x, a: a *…
finefoot
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