Questions on the interpolation functions in Mathematica (Interpolation[], ListInterpolation[], FunctionInterpolation[], InterpolatingPolynomial[], etc.)

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2answers
70 views

Many NSolves to interpolating function

I have an expression of the form: expr = TerribleNumericalFunction[U[p]] == SimpleFunction[p] The Simple function is a ...
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1answer
49 views

Interpolating a function of many variables

I am trying to interpolate a function of 5 variables $$f[m,M,k,v,w]$$ by creating a 5D table of $n$ values in each dimension. ...
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1answer
85 views

Multidimensional Interpolation with 3 independent Variables with modfied data set

I have four column data with first 3 column denoting x,y,z and fourth column energy. x variable is actually angle. Now I want to interpolate over all three indepdent variable (x,y.z) with ...
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1answer
83 views

Using InterpolatingFunction in equations

I tried to use InterpolatingFunction in another ODE, but it doesn't work, because it seems for Mathematica that 2 functions are unknown instead of one. ...
14
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0answers
155 views
+50

How can I smooth a 3D surface generated by RegionBoundary?

I have a set of points that belong to the surface of an object. I would like to approximate a surface to which I can compute the distance. of other points. With the nice code of this post, I was able ...
8
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0answers
186 views

Interpolation on an unstructured (mostly-structured) grid in 4D+

I frequently need to perform interpolations on an unstructured grid. Mostly, with the purpose of filling grid holes and then later continue with regular grid interpolations. Mathematica V9 and V10 ...
8
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0answers
506 views

Creating and using an explicit piecewise function in a convenient way

I have a set of data points that define a function in the form curvePts = {data1,data2,...} where ...
5
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0answers
66 views

Kernel Crash while using “ValuesOnGrid” method of InterpolatingFunction

I was experiencing some kernel crash while using "ValuesOnGrid" method of an InterpolatingFunction returned by ...
4
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0answers
49 views

Multidimensional arbitrary precision spline interpolation on the grid

This question is a generalization of the previous one for multiple dimensions. In the answer to that question an implementation for the clamped spline interpolation for 1D case and arbitrary degree of ...
4
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0answers
405 views

Cubic polynomial interpolation with velocities listed rather than some points

I am trying to use the function BSplineFunction[] to create a natural cubic spline. Normally what is done is that you specify "SplineDegree -> 3" and include a list of points and it will carry out ...
3
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0answers
72 views

Strange extrapolation in ListContourPlot?

I have some Table of {x,y,z} values (energy as a function of radial and azimuthal frequencies in a galaxy if you care to know): ...
3
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0answers
589 views

Interpolate throughout a 3d data list without extrapolation

I have a 3D list of data for which I'd like to plot an interpolated surface. There are several ways to achieve this, but none I cannot find a method which ONLY plots the ENTIRE interpolated surface ...
3
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0answers
403 views

How to make 3D object smooth?

This thread considers mathematical methods here to make the 3D object smooth but this question consider how to achieve the goal of smoothing a 3D object in Mathematica. I want to get smoother ...
2
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0answers
72 views

Defining a region from combination of data and geometric region

I would like to define a region in (x,y) by combining the region RegionPlot[ ImplicitRegion[ Sqrt[x^2 + y^2] <= 0.99, {{x, 0.01, 0.99}, {y, 0.01, 0.99}}]] ...
2
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0answers
47 views

Construct single InterpolatingFunction from a mathematical combination of other IF's

Let's say I have an interpolated function f, like I might get as the solution to an NDSolve: ...
2
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0answers
47 views

Update NumericalFunction in NDSolve

I have NDSolve` StateData from an NDSolve` ...
2
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0answers
170 views

Slow integration of interpolating function

I have a large file with irregularly spaced data in the format: ...
1
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0answers
37 views

Using Quantity[] units causes errors in my calculation

I have an interpolation function in which I wish to use actual units. If I perform the calculation normally, it works fine and returns a proper FittedModel. To illustrate my problem, consider the ...
1
vote
0answers
66 views

Interpolation of Singular Functions

I am trying to interpolate discontinuous (1/R-r)EllipticK[r/(R-r)^2] functions for R in interval $[0,100]$ and ...
1
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0answers
53 views

Conjugate of InterpolatingFunction?

From NDSolve, I got this: {{a1 -> InterpolatingFunction[{{0., 40.}}, "<>"]}} What would be a sensible approach to ...
1
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0answers
81 views

Linear interpolation over 2 variables

I'm tuning a function to data over 4-5 variables using Differential Evolution. The objective function calls frequently interpolation function. I came to a point, where compiling the objective function ...
1
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0answers
100 views

NMaximize and Accuracy

I have a problem with NMaximize which is best depicted by the following figure. The result indicates, that the solution mathematica finds seems to be smooth except a few outliers. How can I get rid of ...
1
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0answers
354 views

Change of coordinates for an InterpolatingFunction

This is a toy example of the question I have but I think it illustrates the point. I have a function y[x] which is an interpolating function. Let's define it ...
0
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0answers
64 views

Polynomial interpolation using Neville's Algorithm

Is there an interpolating function in Mathematica which uses Neville's algorithm? I have written a C++ program to do interpolation using Neville's algorithm and I am getting a small difference ...
0
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0answers
79 views

Interpolation of a NURBS curve

Known that NQ=P where N is the Bspline basis function, Q is the control point that we wish to locate, P is the data points given ( the curve must pass through it) is there any way to modify the "N" ...
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0answers
51 views

Improving RationalInterpolation Result

The following code produces a {4,4} rational interpolation approximation accurate to 10^-6 or better over the range ...
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0answers
32 views

Why numerical functions can't digest InterpolatingFunction with units?

Answering this question gave me the idea that I must be missing something.. In brief, numerical functions generally 'understand' units: ...
0
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0answers
106 views

plotting the stable and unstable manifolds of a difference equation

I have a 2D non-linear system of difference equations for variables x and y defined as follows: ...
0
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0answers
54 views

Combination of interpolations doesn't work?

I have a table valued functions f[i_] and g[i_] and I need to plot various combinations of the function and its derivatives (for example: f''f, f'/f). I tried interpolating f[i_] to ->f[x] and ...
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0answers
70 views

Is there a reason why some specific arrangement of scattered grid points would yield bad RBF (Obtuse package) interpolation results?

I have an arrangement of grid points given by the figure below (the datagrid data is posted below at the end of the post): They correspond to electrode positions of an EEG signal. I am ...
0
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0answers
72 views

Replace parameter of NDSolve by a Function

I dont know how to replace the paremeter inside of an interpolation function result from NDSolve by a function of another parameter. This is it: I have a ...
0
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0answers
279 views

Interpolation of multidimensional data organized logarithmically

The following threads call our attention to the fact that "accuracy of Interpolation will be worse with an unstructured grid", in the context of interpolation of 3d data: interpolation of 3D data ...