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Questions tagged [interpolation]

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

3
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3answers
56 views

Merge pairs in a list that have the same 1st element by averaging the the 2nd elements

I'm trying to do interpolation on a large list of data of the format {{x1, y1}, {x2, y2}, {x3, y3}, ..., {xn, yn}} that is exported from a simulation. ...
1
vote
3answers
74 views

Pass arguments to a function within a function within a function

I want to perform an integration of f[w,t,kx,ky] over t for several different functions f. ...
1
vote
2answers
51 views

Solve from interpolation function

I have the following list and its interpolating finction x1: point={{0., 0.}, {0.2, 1.}, {0.25, 1.5}, {0.3, 1.}, {0.5, 0.}};x1 = Interpolation[point] I would ...
5
votes
0answers
52 views

Why do some uses of PropertyList crash the kernel?

A support case with the identification [CASE:4222617] was created. While looking at the question How to evaluate the "Domain" of an InterpolationObject? I noted that using ...
2
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2answers
82 views

How to evaluate the “Domain” of a Parametric Function?

In a simple example I try to calculate the time the solution x[t] passes a second time x[t]==1. ...
7
votes
2answers
192 views

Complex continuation of an interpolated function

Context I have a complicated real function defined implicitly by a series of imbricated numerical integration. I need to make a continuation of this function for a complex variable which is easily ...
0
votes
1answer
53 views

NDSolve and interpolating function

What could possibly went wrong in my code? Basically, I am solving the differential equation $\textbf{ode}$ using $\textbf{NDSolve}$. But mathematica says, NDSolve::mxst: Maximum number of 10000 steps ...
0
votes
0answers
23 views

Why do I keep getting an interpolation error?

Whenever I run this code, it does not seem to be evaluating anything past the Evecs. There are other definitions/parameters involved in running the code. I am just not sure why it keeps saying "first ...
0
votes
1answer
31 views

How to close the contourplot3D from top?

I received a very nice solution by Chip Hurst to make my 3DContourPlots smooth and closed in here. Now I have another problem that is simpler but I still want to know the ideas of the others. The data ...
1
vote
0answers
17 views

Plotting 3D points with function as contour

so I have a grid of points in 2D $(x_i, y_i)$, and a function $f(x_i,y_i)$. I plotted them together like this: -- Now I would like to do the same with a grid of 3D points $(x_i, y_i,z_i)$ and a ...
0
votes
0answers
30 views

Interpolation of a list defined on a region

I have a three-dimensional table (each element has the form { x, y, f( x, y ) }), and the x, y coordinates spans a region of a parallelogram. If I do a list contour plot of the data, it gives the ...
3
votes
1answer
77 views

Approximating decay rate of an amplitude and frequency of an oscillating function

I have an InterpolatingFunction constructed from a discrete set of values obtained by numerical methods. Let's denote it $f(x)$. The function demonstrates an ...
2
votes
2answers
103 views

Interpolator surface

Writing: ...
0
votes
1answer
66 views

Understanding Energy Function [closed]

I am trying to implement as rigid as possible mesh interpolation solution provided in this article called "As-Rigid-As-Possible Surface Morphing" http://citeseerx.ist.psu.edu/viewdoc/download?doi=10....
5
votes
1answer
118 views

Recycling solutions of multidimensional NDSolve

Dear wolfram community, I hope my problem is clear and easy to solve. I have already solved the following heat equation over a domain: ...
1
vote
1answer
59 views

Use InterpolatingFunction in differential equations involving derivatives and integrals of the InterpolatingFunction [duplicate]

I solved a problem of solid mechanics, 11 unknown components of displacement functions, i.e., ut0[x, y], wt0[x, y], wc0[x, y], .... ...
3
votes
4answers
186 views

Continuous non-piecewise equivalent of smoothstep function?

I have a smooth step function given by the piecewise function ...
5
votes
2answers
72 views

Basic 3D Interpolation Failing

I've seen a few other posts asking about the "unstructured grid" error in Interpolation. Here's a minimal (non)working example of the issue: ...
0
votes
1answer
70 views

InterpolatingFunction gives different result when plot [closed]

I solve a series of ODE equations by NDSolve({t,0,200} is the region), it gives results in the form of ...
-1
votes
1answer
67 views

Interpolation in a data set [closed]

I have the given dataset dat1 = {{0, 0, 1, 10}, {0, 0, 2, 5}, {0, 1, 1, 4}, {0, 1, 2, 3.5}, {1, 0, 1, 0.8}, {1, 0, 2, 0.6}, {1, 1, 1, 0.4}, {1, 1, 2, 0.2}} In ...
0
votes
1answer
63 views

Numerically integrate over an Interpolating function [closed]

I would like to integrate over an interpolating function, which itself is the output of NDSolve in the following code. Unfortunately, I get an error code, saying ...
2
votes
1answer
62 views

Integrating an interpolating function: Hermite vs. BSpline

I have an interpolation through a list of points, which I need to integrate. The minimal working example looks as follows: ...
0
votes
1answer
65 views

Find interpolation with derivatives at some points

I am trying to find out how to find a good interpolation of a periodic function I have from some data points. The only problem is that I need to make sure that derivatives at the starting and ending ...
1
vote
0answers
25 views

how to use interpolating functions to smoothly paint a polygon? [duplicate]

consider 4 different colors on the nodes (with different parameter values) how to interpolate when the color values are given on the nodes using the constructed interpolation functions to paint the ...
3
votes
1answer
54 views

color interpolation using interpolating functions on a quadrilateral

How can I use the interpolating functions I constructed for the four nodes of a quadrilateral to use as parameters to smoothly paint the edges of the quadrilateral when 4 different color values are ...
0
votes
0answers
16 views

Polynomial interpolation using Wachspress construction to interpolate color on a quadrilaterial

My questions is how to use Rational Polynomial interpolants to paint the edges of a quadrilateral smoothly using 4 different colors. My tutor has taught this two-variable version of Pade expansion ...
0
votes
0answers
11 views

How to change to X-axis to actual measurement data instead of showing data point.

I have a question to clarify in the plotting of the graph. How can I change the X-axis to the measured length instead of the total number of the data point which is 16374 points? I need to plot the ...
0
votes
1answer
51 views

Finding the best representation of a numerically-inverted function via InterpolatingPolynomial and/or variations

Below is the routine I am using to sort of represent the numerically-inverted function $TP$. Basically I am finding a necessary interpolating polynomial $TPint$ that fits with the data points given by ...
1
vote
1answer
66 views

Defining the boundary conditions of a PDE

I'm first time use Mathematica and here is my trying of solving equation ...
1
vote
2answers
57 views

How to color the nodes of a quadrilateral polygon

say we have the list of points a = {{1, 1}, {2, 1}, {2, 2}, {1, 2}, {1, 1}},it is a simple square, how can we make color the nodes( in which that the nodes and the ...
0
votes
0answers
29 views

Question on combine data with different length.

Hi I have a problem with the plotting of the graph. There are two separate measurement systems, from the same experiment. One read the encoder data (49K data points), and the other reads the ...
1
vote
1answer
43 views

Interpolation error of InterpolatingPolynomial[]

this is my first post so if I have any error while writing this, I'm sorry. I had to do a polynomic interpolation for one of my lab experiments, and I need to get the error from it in order to ...
0
votes
1answer
55 views

how to color edges of a convex polygon,say a square, using interpolation with respect to the color in Mathematica

How do I color edges of a convex polygon, say a square, using interpolation with respect to the color (to form parametric polynomials) in Mathematica, so that the colors displayed on the 4 edges would ...
1
vote
1answer
42 views

The intersection of two “mesh surfaces from points” which are not convex

After solving the problems with determining the intersection of two mesh surfaces I came across an additional obstacle. Link to the previous question enter link description here Unfortunately, I ...
0
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0answers
29 views

How do I combine `InterpolatingPolynomial` and `Integrate`?

I want to find a real-valued polynomial (or trig) function f[x] that yields 0 at x=-a, and ...
0
votes
0answers
48 views

Representing an interpolating function

I just want to figure out how to "represent" or to inject an interpolating function into a numerical calculation. So, suppose i have an interpolating function $int$ and then i want to use NDSolve or ...
3
votes
2answers
261 views

How do I find a function to fit these criteria?

I want to find a smooth continuous function f[x] that satisfies the following for real values of x: ...
1
vote
1answer
94 views

The intersection of two “mesh surfaces from points”

I am a fresh user of mathematica, soo thank you in advance for your help. I would like to get a list of points (x,y,z) at any interval (eg every 0.05 by x and y coordinate) which are created by ...
2
votes
0answers
96 views

Derivative of an interpolation function is noisy

I have a set of numerical data of 1501 points, in the form of $\{x_i,a_i\}$ which I uploaded to here and here. I need to compute the numerical derivative of this data. In particular, I need the ...
3
votes
0answers
65 views

Deal with noise and missing points in data [closed]

I have run a simulation which has resulted in some bad data (see graph below). What would be the best way to detect and interpolate the missing points in Mathematica (i.e. remove the noise)? Raw ...
2
votes
0answers
52 views

A problem when interpolating the data

I have some data in a form data = {{x,y,f[x,y]},...}, where f[x,y] takes only positive values. When I try to interpolate it, <...
2
votes
1answer
55 views

Find region of given value for linear Interpolation function

Summary: How do I find the (possibly disconnected) region(s) where a linear interpolating function is between two specified values? Example: ...
6
votes
1answer
279 views

What is wrong with this code? (Usage of FunctionInterpolation and how to make code efficient)

I am trying to create an interpolation out of a function that comes from an improper integral. The end goal is to make a 3d plot over a specific region. Specifically, I have the following code: ...
4
votes
1answer
150 views

Interpolation of data

Consider a set of data points ...
4
votes
1answer
219 views

How does this Mathematica code work?

I am trying to work with a simulation of Brain Tumor growth and I was fortunate to get a very great example at http://community.wolfram.com/. However, I need clarifications on some of the code. I ...
6
votes
1answer
129 views

2D interpolation of function with dependent interpolation border

My problem is to compute $$\int\limits_{x_{min}}^{x_{max}}\int\limits_{y_{min}}^{\sqrt{x^{2}-a^{2}}}W(x,y)g(x)\ dx\ dy$$ Because $W$ have highly oscillatory 2d complex numeric integral inside, dumb ...
3
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1answer
62 views

Does `ElementMeshInterpolation` work for arbitrary orders?

Mathematica will not, in general, do arbitrary order interpolation on unstructured grids: ...
0
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0answers
63 views

When I use Plot to plot an interpolating function which is the solution of a big ODEs solved by NDSolve,I found it takes a long time

I'm a Chinese student.I can't speak English very well.If there are any mistakes,please forgive me. I use NDSolve to solve a big ODEs. ...
4
votes
4answers
360 views

How to easily find the coefficients of a cubic polynomial and its plot for the given 4 points

Given 4 points as points = {{0, 4}, {1, 0}, {2, -1}, {3, 0}};. I want to find the coefficients of ...