Questions on the interpolation functions in Mathematica (Interpolation[], ListInterpolation[], FunctionInterpolation[], InterpolatingPolynomial[], etc.)
16
votes
2answers
426 views
Improved interpolation of mostly-structured 3d data
This question arose in response to a comment by Leonid to my answer for this question. He noted that for unstructured grids, Interpolation can only use ...
16
votes
1answer
308 views
How to fix broken InterpolatingFunction?
I have an InterpolatingFunction based on irregularly-gridded data, like this:
...
12
votes
4answers
1k views
Getting the interpolation function from a list plot
I have conducted a chemistry experiment and obtained a list of concentrations of a reactant against time. I plot a graph of this using Mathematica's ListPlot ...
3
votes
2answers
173 views
ListContourPlot interpolation screws up on concave set of data
I want to create ListContourPlots for sets of Data (from a physics simulation) given as Triplets {x, y, f(x, y)}. Certain parameter regions in the x-y-plane are ...
9
votes
2answers
2k views
interpolation of 3D data
I have a 3D surface given in data-points of the form ${x,y,z}$. What is the easiest way to get the interpolated value $z=f(X,Y)$ for given coordinates ${X,Y}$ (which are of course not in the data ...
8
votes
3answers
443 views
Ηow to create an interpolated CDF from its samples?
I want to use a distribution I have only aggregate statistics on, namely its CDF sampled at certain points. I would like to keep it "nonparametric" (remain noncommittal on the parametric form), but I ...
4
votes
2answers
642 views
Is it possible to compute trapezoidal rule numerical integration?
Is it possible to compute trapezoidal rule numerical integration? I know that Mathematica has Interpolation, and that a list of points can be interpolated and then ...
2
votes
1answer
270 views
Interpolating 2D data with missing values
I have a list (21 x 21) containing values. I want to eliminate slots containing zeros by interpolating the nearest values and overwriting the zeros. How do I use the Mathematica's ...
2
votes
1answer
601 views
How do I prevent NIntegrate::inumr errors within other functions?
I believe this question is best illustrated with a simple example. If I run
FunctionInterpolation[NIntegrate[a + b, {a, 0, 1}], {b, 0, 1}]
I get errors of the ...
17
votes
2answers
505 views
Joining and interpolating data points
I wonder what is the best practice for interpolating curves? Usually I'm using BSplineCurve and adjusting SplineWeights so it ...
12
votes
2answers
428 views
Higher order periodic interpolation (curve fitting)
I have a list of points in 3D, and I want to get a smooth interpolation or curve fit (it is more for illustration) of these points such that the first and second derivatives at the start and end ...
27
votes
3answers
386 views
No warning when extrapolating with Plot
One of the most annoying "features" of Mathematica is that the Plot family does extrapolation on InterpolatingFunctions without ...
10
votes
1answer
220 views
How to get zeroth-order (piecewise constant) interpolation of scattered data?
Given a collection of scattered data points in 2D and associated function values,
data = RandomReal[1, {100, 3}];
we can get a piecewise linear interpolating ...
12
votes
3answers
235 views
How to splice together several instances of InterpolatingFunction?
I have a set of InterpolatingFunction returned by NDSolve which are valid over different (but overall continuous) domains. How ...
12
votes
4answers
351 views
How to reduce the InterpolatingFunction building overhead?
I want a linear interpolation from the following example list:
...
10
votes
3answers
430 views
Derivatives (divergence, gradient, curl) of interpolated 3D data
How can I calculate a vector derivative (i.e. divergence, gradient, curl) of interpolated data? For sample data, you can use:
...
8
votes
1answer
97 views
Prevent Plus from threading InterpolatingFunction
For an InterpolatingFunction $y:\ \mathbb{R}\to\mathbb{R}^2$, Plus is unaware of this, so when I do any modifications to it in ...
5
votes
1answer
173 views
3
votes
2answers
114 views
Convert BSplineFunction into two Interpolating Functions
Is there a way to decompose a BSplineFunction output into two functions x[t], y[t] ...
14
votes
1answer
214 views
Why does LogLinearPlot sample its argument outside the specified domain?
I experience a weird bug in the function LogLinearPlot. If the input is an interpolation function, such as the one created like this,
...
10
votes
2answers
388 views
Interpolation of mostly-structured 3D data
this question relates to interpolation of 3D data and Improved interpolation of mostly-structured 3d data
I have an irregular 3d data set that is quite large (around 70,000 triplets---let's call it ...
5
votes
2answers
129 views
How to get the boolean value of an inequality involving an InterpolatingFunction?
Here's the code:
yan = FunctionInterpolation[x^2, {x, -1, 1}];
FullSimplify[yan[x] > -1, -1 < x < 1]
Needless to say, what I expect to see in the output ...
