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

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3
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0answers
75 views

Data Interpolation of deaths by date

I am working with an ebola dataset from Guinea, 2014:(http://currents.plos.org/outbreaks/article/estimating-the-reproduction-number-of-zaire-ebolavirus-ebov-during-the-2014-outbreak-in-west-africa/). ...
5
votes
0answers
73 views

InterpolationOrder has no effect on ListContourPlot when the data is of the form {x,y,f[x,y]}

This is related to the issue brought up here, if you want to mark it as duplicate feel free to do so, but it is slightly separate. Take two sets of data, identical except for the form, ...
1
vote
1answer
66 views

Accurate Integration of 2D interpolating function with weighting

I want to integrate a 2D interpolating function received from NDSolve[]. To illustrate my problem I will give a simple example: ...
8
votes
3answers
1k views

Suppress extrapolation of interpolating function in a ContourPlot

I have defined an interpolating function, myfcn[x], valid on the domain x = 0 to 1.5. I am then using ...
0
votes
2answers
66 views

List of points of an increasing sine function

I'm trying to obtain a list of the points of an amplitude-increasing sine function. I would like to give a certain value for input, e.g. 0.5. Sine will start increasing and decreasing from this point, ...
5
votes
4answers
264 views
20
votes
3answers
4k views

Data interpolation and ListContourPlot

I am fairly new to Mathematica and I have two quick questions on using it for a Hydrology and Hydrogeology class. One is about data interpolation and interpolating without any data defined in an area. ...
0
votes
1answer
68 views

Getting numerical values from integrated interpolating function [duplicate]

I have a list of data. I integrate them with interpolation. Lets say is the following: InterpolatingFunction[{{0.01, 4.82}}, <>][x] However, is that ...
1
vote
2answers
98 views

Get value from InterpolatingFunction

I'm trying to find My[t], Mx[t] and Mz[t] values when evaluated at ...
3
votes
0answers
56 views

Problem with MissingDataMethod [closed]

Given v = {2, 1, Missing[], 5, 7, 4}; I use EventSeries to replace the missing value with its predecessor ...
3
votes
1answer
211 views

Hermite method in Mathematica

When I solve the example below, in the results it is mentioned that Mathematica 10 has used the Hermite method. I cannot find anything about this in the Mathematica documentation. Is there nothing ...
4
votes
3answers
195 views

How to read the intersect corodinate of two lines from the ListLinePlot?

Suppose I have two curves intersect at some point, how can I read the coordinates from the graph, not read by eye, but find it with more precision by computer. For example, here are two lists created ...
3
votes
1answer
116 views

SystemException with Interpolation

Consider the following sample code Interpolation[{Range[20], 2*Range[20]}]; ...
3
votes
0answers
95 views

Data smoothing in three dimensions [on hold]

I have data with statistical fluctuations of the form $f(x_i,y_i)$ over a discrete grid. I now need the values of $f(x,y)$ also at points other than the grid points. That can be achieved by ...
2
votes
1answer
49 views

ndsolve interpolatingfunctions not shown/evaluated

Using this technique from Simon, I want to solve a matrix differential equation with a matrix that contains an explicit time-dependence(our variable), but I want to be able to solve this problem for a ...
5
votes
1answer
153 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 ...
1
vote
2answers
1k views

Cubic Splines Functions

I have this set of three data points and want the natural cubic spline functions for them: dat = {{-.0247500, .5}, {.3349375, -.25}, {1.101000, 0}}; I tried: <...
0
votes
0answers
96 views

Absurd solution by LinearSolve

I am trying to find curve that passes through all the data points.To do this i am doing interpolation using LinearSolve. No. of equations vary from 1000 to 3000. LinearSolve gives me values of ...
2
votes
2answers
179 views

BSpline or other curve through arbitrary ordered sequence of two-dimensional points

How does one create a BSplineCurve or other smooth curve passing through each point in an ordered list, where the curve may be non-simple, i.e., can double-back ...
23
votes
3answers
972 views

Arbitrary precision spline interpolation

The current implementation of Interpolation does not allow arbitrary precision spline interpolation. Yu-Sung Chang says here that "it is not hard to implement it ...
2
votes
3answers
149 views

Extract function from a parametric interpolating function

I've read the answers of How to make use of an interpolating function outside of Mathematica?, Interpreting the interpolating function and saving data to plot with external program, Extracting the ...
4
votes
1answer
125 views

How to get coordinate from spline interpolation

Hi, I would like to find 10 coordinates between each points of this spline interpolation. I have done some research, but cannot find an appropriate answer. Any help will be appreciated. ...
1
vote
0answers
88 views

Determining the order of continuity (smoothness) of a function

Is there any method to determine the order of continuity of a function (just like an interpolant) over a given domain, or at least determine the continuity on a given order? For example, according to ...
2
votes
1answer
174 views

Working with Interpolating Functions

I have two sets of data that are not regularly sampled, and I want to produce a quantitative measurement of how similar they are while fitting them with an $x$ shift and $x$ and $y$ scaling. ...
3
votes
1answer
127 views

Repeated interpolation for 3D unstructured grid -> Optimization

Trying to perform mesh-to-mesh 3D interpolation on unstructured grid. Mesh size is about 200k nodes. Painful thing that interpolation shoud be repeated ~1000 times (different thermal map) on the same ...
5
votes
1answer
99 views

How to get `FindCurvePath` to return only one list

As you can see below, FindCurvePath returns only a part of the list, resulting in a partial interpolation. I would like to interpolate all the points. Complete ...
3
votes
0answers
80 views

Diagonalisation of equations for NDSolve

I have a linear matrix differential equation and I wish to speed up evaluation by diagonalising using eigenvectors. There is an example in Help for finite elements under "swinging beam" that is ...
7
votes
1answer
117 views

How do I reverse the X-axis on a ListDensityPlot?

I want to use ListDensityPlot on a dataset containing a few (~600) triplets and I would like to reverse one of the axes. Sadly, the workaround involving the ...
8
votes
3answers
283 views

Linear interpolation of elements in a list to generate new list

For a list of any given length, I want to generate another list from it adding elements which are mean of the consecutive elements, in between the elements, of the original list. For example: ...
2
votes
2answers
130 views

How to store an InterpolatingFunction? [duplicate]

Assume I have obtained an InterpolatingFunction, say, as the result of solving of a differential equation, say, this one: ...
4
votes
1answer
116 views

Finding the attractors of the vector field constructed as the gradient of an interpolated 3D scalar field

I have a list of data existing as {{{x, y, z}, f},...} from which I construct a 3D interpolation function using Interpolation[ ]. I am able to construct a vector field from the gradient of this scalar ...
1
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0answers
60 views

Continuous integration of a tensor function using discrete density values

Hei, I am wondering is it possible to implement continuous integration using Integrate() of a fourth order tensor with discrete density values. ...
3
votes
1answer
131 views

Interpolation of ListContourPlot3D, Volumetric data (cube file)

I know there are lots of information about this on stack exchange! Data interpolation and ListContourPlot InterpolationOrder for ContourPlot Unfortunately I was not able to find a proper way to ...
5
votes
2answers
146 views

FunctionInterpolation and Which combine badly

Update 2: Got two solid answers, but had trouble implementing one, and found the other could only save me computation time by sacrificing accuracy. So I chose neither as an official answer, but they'...
3
votes
3answers
125 views

Combination of interpolations doesn't work?

I have tables of function values f[i_] and g[i_] and I need to plot various combinations of the function and its derivatives (...
6
votes
1answer
187 views

How to avoid creating negative values when using Interpolation?

I'm having some problems with Interpolation. I'm trying to interpolating some measurements data into mathematica. But using Interpolation will create some negative data, which is actually not possible ...
0
votes
0answers
116 views

Linear interpolation over 2 variables [duplicate]

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 ...
2
votes
0answers
131 views

Interpolation of Singular Functions

I am trying to interpolate discontinuous functions for R in interval $[0,100]$ and r in interval $[0,100]$: ...
3
votes
1answer
77 views

Table generation with SetDelayed function [closed]

I would like to understand why the following two outputs differ: Let us define the following data set: ...
1
vote
1answer
81 views

How do I restrict the range of an interpolating function in NDSolve?

I have a numerical solution for a differential equation. I know that the gray dotted solution is unphysical. Is there a way I can tell mathematica to ignore the gray dotted solution (e.g. restrict the ...
8
votes
2answers
334 views

How can I speed up my compiled RBF interpolating function?

Overview I have a function that acts like the Interpolation on sparse $n$-dimensional data using a simple implementation of RBF interpolation method. I want my ...
1
vote
1answer
61 views

Can list interpolation be made listable? [closed]

I have 8 sets of 2D-data that I want to each interpolate with ListInterpolate, because it is a very efficient command. The complete data are therefore in a 3D table....
1
vote
3answers
133 views

Many NSolves to interpolating function

I have an expression of the form: expr = TerribleNumericalFunction[U[p]] == SimpleFunction[p] The Simple function is a ...
2
votes
2answers
313 views

Interpolation showing noise in “non-noisy” data set

Stuck trying to get the interpolating function to match the (what I thought was a) smooth point set, how best to deal with this? Many thanks. ...
4
votes
2answers
282 views

NMinimize Constraints on Interpolating Functions

I have the following piece of code and am trying to use NMinimize (the last line in the following chunk of code) to minimize ...
5
votes
1answer
104 views

Second derivative of SmoothKernelDistribution PDF?

Does anyone know why I can't seem to get a second derivative of this interpolating function f? In this example, h[x] is zero ...
7
votes
1answer
222 views

Smoothen the curve found by EdgeDetect

It seems that curves found by EdgeDetect always persist $C^{0}$ continuity only. Consider the following example: ...
15
votes
1answer
458 views

Why does LogLinearPlot sample its argument outside the specified domain?

Bug introduced in 6.0 and fixed in 9.0.0 I experience a weird bug in the function LogLinearPlot. If the input is an interpolation function, such as the one ...
9
votes
1answer
162 views

Kernel Crash while using “ValuesOnGrid” method of InterpolatingFunction

Bug introduced in 10.0.0 and fixed in 10.2.0 I was experiencing some kernel crash while using "ValuesOnGrid" method of an ...
6
votes
2answers
223 views

What's the difference between Interpolation[pts, Method -> Spline] and BSplineCurve?

Last month, I answered a question about spline interpolation,please see here Now I do the following operations ...