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Questions tagged [interpolation]

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

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1answer
46 views

Numerically integrate over an Interpolating function [on hold]

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 ...
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1answer
48 views

how to generate a bezier curve using 4 points(arbitrary), without using the built-in function of Mathematica?

the main point is that we do not use the built-in function in Mathematica, instead use a step-by-step program to solve it?
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1answer
36 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: ...
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1answer
48 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 ...
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0answers
23 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 ...
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1answer
44 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 ...
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0answers
13 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 ...
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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 ...
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1answer
37 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 ...
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1answer
61 views

Defining the boundary conditions of a PDE

I'm first time use Mathematica and here is my trying of solving equation ...
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2answers
48 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 ...
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0answers
27 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 ...
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1answer
36 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 ...
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1answer
52 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 ...
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1answer
36 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 ...
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0answers
28 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 ...
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0answers
43 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 ...
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2answers
221 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: ...
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1answer
78 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 ...
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0answers
92 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 ...
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0answers
61 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
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0answers
42 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
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1answer
51 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
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1answer
275 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
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1answer
141 views

Interpolation of data

Consider a set of data points ...
4
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1answer
217 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 ...
3
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1answer
106 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 ...
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1answer
57 views

Does `ElementMeshInterpolation` work for arbitrary orders?

Mathematica will not, in general, do arbitrary order interpolation on unstructured grids: ...
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0answers
61 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. ...
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4answers
353 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 ...
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1answer
105 views

How can I obtain the domain of a resulting Interpolating Function?

I have a problem with obtaining the domain of resulting Interpolating Function in my calculations. I want to solve the following differential equation ...
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1answer
94 views

Several errors with InterpolatingFunction [closed]

I'm getting some error messages that don't make sense. Apologies, as the code is somewhat complex. Basically what I'm trying to do is solve a system of differential equations, then fill a table with ...
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4answers
131 views
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0answers
76 views

Analyzing MethodOfLines

In this example the wave equation ...
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1answer
54 views

Solve an ODE involving an Interpolating function with Mathematica

Using Mathematica, I want to solve an ODE of an Interpolating Function. First I solve the ODE obtaining the function y[s] (or Y[s]) ...
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0answers
54 views

Contour lines in ListContourPlot with InterpolationOrder 0

I have a dataset and would not want Mathematica to interpolate at all while plotting the contours. This is because the data contains essential binning information and the "steps" in the contour must ...
2
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2answers
100 views

Curve fitting, Polynomial [closed]

I have a data set in such a manner ...
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0answers
48 views

Accuracy of Chebyshev Interpolation

I have been looking at how to interpolate a function using Chebyshev polynomials. There are several good posts such as this one by Michael E2 and this one by J.M needs help. There is also an example ...
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0answers
42 views

Parallelize Slow on Interpolated Functions

So I have an FEA solution from COMSOL and I import the mesh and values at the vertices to create an interpolation function. ...
2
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1answer
90 views

How to interpolate closed surface

With BSplineSurface, I was trying to interpolate data points belonging to a sphere, but unfortunately I don't get the right geometry closing: ...
2
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2answers
156 views

Interpolation function

I am facing a problem in getting a smooth plot of following data. ...
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1answer
44 views

Shifting the domain of an interpolated function

If I interpolate a list f=ListInterpolation[{1,2,3,4,5,6,7}] the result is in the domain {{1,7}}, so something like ...
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1answer
59 views

Interpolation order reduced to 1 due to unstructured grid error; yet proper syntax?

I am attempting to do a second or third order interpolation on a grid of 2D data with 1D output; i.e. a scalar function on the complex plane. However, when attempting to do: ...
6
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1answer
87 views

Efficiently fill sparse matrix involving BSpline

Context In order to implement regularised fitting in 2 or 3 dimensions (as is done say here) using BSplineBasis one needs to evaluate a basis over a set of data. ...
2
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1answer
140 views

Derivative of an interpolating function

I have an interpolating function (which comes from an integral that cannot be done analytically), it looks nice and smooth: However, since what I need is the derivative of this function, it is not ...
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1answer
52 views

Is there a way to gather the points used in a Plot and generate a function that passes through those points?

like the title says: is that possible? In my case, I have a plot of an integral that is evaluated numerically. Maybe using Interpolate with the points used by mathematica to draw the graph or ...
2
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1answer
67 views

Interpolating and plotting from a list

I have a dataset in this form (but much bigger of course): ...
0
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1answer
28 views

Plot interpolating function depending on free variable inside manipulate

I create an interpolating function which depends on some free variables. I then want to plot it inside a manipulate, but my output is empty. What am I doing wrong? ...
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1answer
70 views

Finding the $y$ value of an interpolated function given an $x$ value

I am trying to interpolate my dataset, which is a list of points. Thus I have two interpolated functions of my x data and y data: ...