Matthew Hunt
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I am trying to solve a pair of coupled linear PDEs using backward Euler and Newton-Raphson
I am tring to solve a coupled pair of 1D PDEs in time and space using the backward Euler and Newton-Raphson. One of them is a hy...
1 year 前 | 1 个回答 | 0
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Can I include an ODE when I solve a system of PDEs in pdepe
Suppose I have a moving boundary problem and I have an ODE governing the length of the bounary I am interest in. Is it possible ...
1 year 前 | 1 个回答 | 0
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Code has numerical issues that I don't understand
I managed to get a system of PDEs down to a large system of ODEs via the method of lines. I managed to code it up using ode45 bu...
1 year 前 | 0 个回答 | 0
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How do you include a mass matrix in ode45?
ode45 solves a set of equations The length of is 3N+1, I have a non identity mass matrix M, but I've not seen any real ins...
1 year 前 | 2 个回答 | 0
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User defined function within ode45
I have the following ODE system: If f(t) is a constant, then I can easily write the code, but I have f(t) as a piecewise ...
1 year 前 | 2 个回答 | 0
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Can I get a better fit to data
I've written a code to find some parameters to a mathematical model but I can't seem to get a good fit to the experimental data....
2 years 前 | 1 个回答 | 0
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Use of fmincon with objective function as m-file
I am finding parameters for a model. I thought the best thing was to define the objective function that I wiah to minimise as f...
2 years 前 | 2 个回答 | 0
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Can we get functions from the curve fitting toolbox?
I am using the curve fitting toolbox and I have some data that I want to create a function from. I am using a spline function to...
2 years 前 | 2 个回答 | 0
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Solving PDEs with mixed derivatives
Suppose I have an equation of the form: Can I use pdepe to solve that equation as is, or do I have to do a co-ordinate tran...
2 years 前 | 1 个回答 | 0
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Implementing Crank Nicholson in spherical setting
I am trying to solve the spherical diffusion equation using the Crank-Nicholson method. I think that I understand the method, I ...
2 years 前 | 3 个回答 | 0
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Code doesn't terminate in the way that I want
I have a loop which changes the value of a vector at each iteration of the loop. I don't want the values in the loop to get grea...
2 years 前 | 1 个回答 | 0
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My implemetation for Newton's method doesn't seem to be working
My goal is to solve the following set of nonlinear equations: for this I use the Newton method in the form: The code t...
3 years 前 | 1 个回答 | 0
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I want to do a 1D integral of some 2D data
Suppose I have a function which is defined as some numerical data which is equally spaced and I wish to compute: How would I...
3 years 前 | 2 个回答 | 0
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Speeding up pdepe calculation
I have a pdepe bit of code I want to speed up if I can. I have a (typically) 400x800 array as a source term, the code I'm curren...
4 years 前 | 0 个回答 | 0
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Importing a two variable function into pdepe
Hi I want to solve a diffustion pde I understand how to do this if Q is a single variable function using interp1, but I do...
4 years 前 | 1 个回答 | 0
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How do I include a user specified hessian function for fmincon?
I am working on an optimisation code and I have a Hessian function I wish fmincon to use. I'm currently having trouble trying to...
4 years 前 | 1 个回答 | 0
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Is it possible to store the intermediate values of fmincon?
So I had to do a lot of searching and turns out that this is possible without downloading code. The key was to use 'OutputFcn' i...
Is it possible to store the intermediate values of fmincon?
So I had to do a lot of searching and turns out that this is possible without downloading code. The key was to use 'OutputFcn' i...
4 years 前 | 1
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Is it possible to store the intermediate values of fmincon?
If I'm runnning fmincon, and I want to see the values of the parameters at each iteration, is there a way to do this? The docum...
4 years 前 | 5 个回答 | 0
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Defining a stopping criterion for fmincon
I am looking at an optimisation problem with the following objective function: ...
4 years 前 | 1 个回答 | 0
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Objective function doesn't converge but jumps around
I have been trying to complete an optimisation problem. I am looking at radial heat diffusion on a cylinder. I want to tackle it...
4 years 前 | 0 个回答 | 0
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Crank Nicholson method for cylindrical co-ordinates
I am trying to solve the heat equation in cylindrical co-ordinates using the Crank-Nicholson method, the basic equation along wi...
5 years 前 | 0 个回答 | 0
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Converting anonymous function to a matrix
I have a function of the form: , which I want to evaluate. I could do this old school with a double loop but that would take t...
5 years 前 | 1 个回答 | 0
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Diagonal matrices with spdiags
I'm working on a numerical solution to an equation and as part of this I have to solve a matrix solution. The system of equation...
5 years 前 | 1 个回答 | 0
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Is there a way of removing these for loops to speed up my code?
I have the analytical solution to the following PDE: with boundary condition and and initial condition in the form of a Gr...
5 years 前 | 1 个回答 | 0
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I have: Error using bsxfun Non-singleton dimensions of the two input arrays must match each other.
So I have some code which I want to get working and I don't understand the error which is being given to me which is: Error usin...
5 years 前 | 2 个回答 | 0
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Interp1 returns NaN for a value
I have some data (x,f(x)) where 0<=x<=1 and I have N points. I wish to obtain f for an inteverval [a,b] which is well within the...
5 years 前 | 1 个回答 | 1
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Tracking the size of a variable
Hi, I have a vector of length 200. When I run my program it somehow halfs in length, and I have no idea why. Is there a way of ...
5 years 前 | 1 个回答 | 0
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个回答已回答
Not enough input arguments when doing global optinisation
I've seen what I need to do. The set up of the function is different to lsqcurvefit: I had to define the function as: fun = ...
Not enough input arguments when doing global optinisation
I've seen what I need to do. The set up of the function is different to lsqcurvefit: I had to define the function as: fun = ...
6 years 前 | 0