Questions tagged [interpolation]

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

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79 views

Maximize a function with an interpolating function as a constraint

Consider the following interpolating function, i, which is constructed using the data here. ...
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76 views

Retrieving values from InterpolatingFunction

I have code for finding the flight of a golf ball and I would like to retrieve the values of horizontal displacement x[t] and at the time when the golf ball hits the ground (y[t]=0, when t=tmax) <...
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101 views

How to quickly evaluate the same interpolating function many times?

i am trying to use NDSolve on a set of coupled ODEs (roughly 200 equations). In each equation an interpolating function has to be evaluated many times at the same point respectively. So for example ...
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42 views

Resampling method: `HoldValueFromLeft`, what is this?

I came across the Resampling method: HoldValueFromLeft: As this method is not explained by the official documentation, what is the meaning of it? Also, as a ...
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34 views

Confusion over constructing interpolation functions from tables

Suppose I have a set of functions: f[x_] := x^2; g[x_] := (f[x])^2 +2*f[x]; h[x_] := 2*f[x]+5*g[x]; I tabulate the first two functions over ...
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46 views

Generating the best-fit formula for given data

I have three independent variables and one dependent variable, I want to generate a new formula for calculating the dependent one using the three independent ones, I have the data series like below: <...
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21 views

Interpolation does not give continued function [duplicate]

I am trying to interpolate experimental data. everything seems to work well but the function is not Continuous. Any idea why? ...
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41 views

Interpolation undefined on domain

I have made an interpolation of two variables of a fairly large set of numbers imported from a file (4 million lines in an .m file written out with C++). The ranges of the two parameters is 0 to 2.5 ...
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1answer
116 views

How can we extract the points of a level-set from a 2D Interpolating function? [duplicate]

Let us assume that we have a 2D Interpolating function u[x,y]. We can plot its contours by ...
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67 views

VariationalBound with and interpolated trial function

I am trying to solve a Sturm-Liouville problem using the VariationalBound function of Mathematica, as recomended in the wolfram mathworld site. The example given in the Mathematica documentation is ...
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54 views

Storage of interpolated data

I successfully imported some optical data to Mathematica, which I need to interpolate to use it as a proper function. The command data=Interpolation[] was quite ...
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1answer
372 views

Defining a function using an InterpolatedFunction from a data set

suppose I have two data sets A and B, which are tables/lists/arrays/whatever Mathematica calls it, from an imported CSV. there'd be lines that look like this: ...
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110 views

How to plot an interpolating function from data showing the median values and the scatter around the medians

I have a list of data points $x_{i}$, $y_{i,16}$, $y_{i,50}$, and $y_{i,84}$ where $y_{i}$ respectively correspond to $16th$, $50th$ and $84th$ percentiles value of the function at positions $x_{i}$. ...
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77 views

Check if interpolated function passes through a specified region

Is there an efficient way to check if a curve that was obtained as an Interpolating Function (from solving differential equations numerically) passes through a given region? I am solving for two ...
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141 views

Taking the derivative of the complex conjugate/absolute value of an interpolating function

I have following code: ...
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1answer
71 views

How to define InterpolatingFunction on a variable set of points?

I would like to define an InterpolatingFunction to which data points are transferred as a parameter, e.g.: ...
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226 views

Interpolation of 4D data on a triangular grid

I need to interpolate a function defined on a triangular surface (grid). The grid is defined as ...
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1answer
76 views

define function with 3d discrete points and find corresponding value from that function [duplicate]

Now I have a set of 3d discrete points in the form of {x,y,z} and want to interpolate them and define them into a function making x and y as the variables. Subsequently read corresponding values of z ...
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1answer
245 views

List manipulation performance or how to make independent list copy

I have a task to solve some system of equations with NSolve and print graph of it, depends on parameters. Something like this (maybe it is not a good example and does not always have a solution, but ...
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60 views

How does Mathematica interpolates? [duplicate]

In manual for Interpolate function it is said, that possible method of interpolation is Hermite. Unfortunately, I can't see ...
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126 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 ...
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38 views

FindRoot gives strange results when used on an interpolating function with vector output [duplicate]

I am currently experiencing a problem when I try to use FindRoot with an interpolating function that outputs a vector. I have constructed a minimal example that ...
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621 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 ...
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1answer
609 views

How can I interpolate this data? [closed]

...
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1answer
76 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 ...
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1answer
147 views

Interpolation curve [closed]

I have a complicated parametric curve which takes too long to integrate, therefore I want to sample points and interpolate to speed up calculations. The curve is: ...
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1answer
1k views

Interpolating Function inside of NDSolve

I have a problem and it seems to be connected to an Interpolating function inside of an NDSolve command. The resistivity[x] ...
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1answer
120 views
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1answer
100 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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1answer
303 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. ...
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429 views

How to interpolate this list of data

Can anyone help me to interpolate this list of data? I try to use Interpolation function but think the number of points it's not enough. Here I show the result using ListPlot: I want to ...
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4answers
5k views

Piecewise linear Interpolation between data points [closed]

Is there some sort of functionality built into Mathematica that will let me linearly interpolate between (x, y) pairs of data in an array? Example: I have the two points (1, 10) and (2, 20), how can ...
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1answer
138 views

Interpolate/extrapolate a gate charge curve from two different curves

Gate charge measured data. I have gate-charge measurement plots and Excel data for two operating points for a power MOSFET. Vds = 60 V, Id = 50 A Vds = 600 V, Id = 8 mA Can I generate a plot with ...
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1answer
469 views

Create a spline function to interpolate a 3D surface [closed]

Here's my problem, I have an spreadsheet that contains data, a 202x202 matrix with x,y and z coordinates. The objective is import the data to mathematica, and then I need to create an interpolation ...
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2answers
699 views

Aitken interpolation of a polynomial?

How I can approximate a polynomial using Aitken's scheme using two nodes for the interpolation? ...
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1answer
285 views

How to approximate the data curve with a function? [closed]

I want to approximate a data curve (the purple curve in the picture) with one function, so I can use it in my engineering simulation. Some explanation of purple curve The curly part is a sinusoid; ...
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1answer
480 views

Problem with interpolation [closed]

I have a problem with the function interpolation. when I use it my points are all very shifted. Do you have an idea of the solution? ...