# Questions tagged [interpolation]

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

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### Removing some data and replacing them with new ones

I have a data list where the elements have the form (time, velocity ). I need to remove some malformed elements in places where the data does not change smoothly and then replace those points by ...
700 views

### Interpolation of a table with 4 parameters

I have a huge data file which I need to do some analysis on it. The file is built in this way that for each 4 variables, there is a value of the function: ...
276 views

### Partitioning a numerical integral: need to integrate spectra

I am trying to integrate a spectrum I obtained from a fourier transform infrared spectroscopy experiment, in order to determine the global warming potential of green house gases. In order to do this, ...
617 views

### Interpolation problem on the list

I have a List of Latitude, Longitude and Measurement. a = {{{93, 104}, 290}, {{94, 103}, 292}, {{95, 105}, 291}, {{97, 109}, 294}, {{97, 102}, 295}}; And, I ...
919 views

### Optimizing the fitting of Ordinary Differential Equation(NDsolve) involving interpolation functions

I am a newbie to this forum. I am trying to use NDsolve to solve some ODEs involving the interpolation function. Then, I will compare the fitted curve and data to determine the ODE coefficients. ...
98 views

### FEM 1D 3D region coupling - integration too slow for coupling with energy conservation

EDIT: I reposted this question, removing everything that is not necessary for my coupling approach. Find the new post here. I am working on a 3D simulation of the heat equation which is coupled to a ...
43 views

### Integrating and seeing an interpolating function

I have the following piece of a Mathematica notebook: As I understand, the interpolating function M1hatInterp is piecewise polynomial and hence can be integrated ...
38 views

### Why ListInterpolation does not allow InterpolationOrder greater than 2 in the "y" direction?

The order is always reduced to 2 in the "y" direction; I would want a better approximation to my data. Independent of the method (spline or hermite), I can choose any order for the "x&...
50 views

### Interpolation for different Parameters

I am rather new to Mathematica and I tried to find a solution for my Problem on my own, also looking through this site and the suggested Similar Questions, but I at least could not make out that my ...
97 views

### linear interpolation error [closed]

I have two set of data for pressure and energy density and I used a linear interpolation to apply the data as a function in terms of each other. ...
45 views

### Finding specific x value when y axis is zero [closed]

If I have the following data: https://pastebin.com/4F7R0nW0 Which plotted using ListLinePlot[data, PlotRange -> {{80, 110}, {-0.020, 0.05}}] gives: Question: ...
93 views

### Integrate over one variable of a 2D interpolating function returned from NDEigensystem

I'm trying to implement the answer for "Integrate only one variable of a 2D interpolating function" (https://mathematica.stackexchange.com/a/161962/73672) but for interpolating functions ...
28 views

### Variable order in InterpolatingFunction

I'm attempting to deal with a interpolating a function $f[x,t]$ on an unevenly spaced grid of $n$ points. My x-variable is continuous, so there's no difficulty in fitting a cubic spline to it with ...
74 views

### Numerical Definite Integral of Numerical Laplace Transform

I'm having problem taking the numerical definite integral of a numerical Laplace transform that depends on two variables due to NIntegrate:inumr errors: ...
70 views

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### Unable to Solve Area Using Paramteric Equations derived from The Numeric Soution of a Differential Equation

I'm creating a test that measures the distribution of closed shape $\mathcal{C}$. This requires taking the average ray length (from $(u,v)$ in $\mathcal{C}$ to the boundary) using ray length per ...
399 views

### InterpolatingFunction::dmval error in the Piecewise function with an interpolation funcion included

I have a set of data, first I deal the data with an Interpolation function. excitef1 = Interpolation[ps1] Then I use a Piecewise function to expand the range of ...
76 views

### Speeding up a minimisation involving Numeric integral and Interpolating function

I am doing a minimisation procedure to obtain best fit parameters a,b,NN for a model involving a numeric integral and an interpolation function. The code as written ...
146 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 ...
68 views

### How do I find the best fit line which passes through a series of data? [closed]

I have a list of data and want to create a function which passes through them. I'm new to Mathematica and don't know how to do this work. Could anyone explain this topic with fitting the below data?...
43 views

### Interpolation with order All function object not given as output

I use mathematica10.4 and want to interpolate uneven data in 3 independent variable, (say r1, r2, r3). Because it is an unequally spaced data, I prefer interpolation order->All. But when I run the ...
136 views

### Understanding the structure of an InterpolatingFunction [duplicate]

FunctionInterpolation[x^2, {x, 0, 9}] // InputForm returns: ...
97 views

### Using FindMaximum on one component of a vector-valued function

I've got a physics simulation that uses NDSolve and returns a vector-valued InterpolationFunction, by which I mean that the <...
446 views

### How can I suppress InterpolatingFunction::dmval message? [closed]

I'm getting this error again and again even though I have interpolated my function from -3 to 3. InterpolatingFunction::dmval: Input value {-2.99957,-2.99957} lies outside the range of data in the ...
72 views

### 3DPlot, Logarithmic x and y axes, Interpolating function [closed]

I've used NDSolve to get an InterpolatingFunction that solves a certain difeq. I want to see the behavior of this function on a couple different scales, so I want to use some sort of Log Plot. For a ...
166 views

### DeleteDuplicates [closed]

After having applied "DeleteDuplicates" to a list of data (15000 rows per 3 columns), when I try to interpolate that list of data it gives me back again: "There are duplicated abscissa points in.." ...
556 views

### Smoothing ListContourPlot contours for unstructured grids. Part 2

My question is motivated by the following discussion. Smoothing ListContourPlot contours I need to generate high-quality contour plots for some property generated on a non-rectangular grid. This is ...
581 views

### Obtaining values from interpolating functions

A similar question has been asked in the post HERE but the current question is more complicated: I have the following differential system ...
426 views

### How to use interpolating functions in NSolve with a piecewise function?

I have a system of two non-linear differential equations that are piecewise, the solutions of which I would like to use to obtain the values of a third variable that is also piecewise. I have trouble ...
542 views

### Getting FindRoot::nlnum when trying to find root of an Interpolating function [closed]

I want to solve a system of differential equations and find a point where the solutions cross. So four steps: 1. Solve the system of differential equations: ...
142 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 ...
290 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 ...
83 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. ...
112 views

### Improving RationalInterpolation Result

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

### Show actual Interpolation function [duplicate]

Is there a command to show the actual function when using the Interpolation command? For example, f = Interpolation[{1, 2, 3, 5, 8, 5}] returns ...