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David H


UCL

Last seen: 4 years ago |  Active since 2014

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Answered
can anyone help me implement this?
Check out the documentation of "ode45", this should give you some idea of where to start. This uses the Range Kutta shooting me...

4 years ago | 1

Answered
Having trouble making a for loop equation
It isn't obvious what you are trying to do, you have a 3D function and want to fit an order 8 polynomial to it in z only? In ...

4 years ago | 0

Question


Simulating lens tilt on image
I am currently trying to simulate the effect of lens tilt on a flat image (i.e., one that does not contain multiple depths of fi...

4 years ago | 2 answers | 0

2

answers

Question


Close all figures which are not docked
Is there any easy way to close all figures which are not docked? Either a high level command or a way to loop over figures and ...

5 years ago | 2 answers | 0

2

answers

Answered
I have a function that gives two outputs, what is the easiest way to use fzero on only the second output
No good way of doing this within Fzero, people have made that clear.

5 years ago | 0

| accepted

Answered
Using function syntax with stand alone executables
Having looked through all the answers to do with this, it appears it is just truly awful. I'm tempted to make a wrapper of the ...

6 years ago | 0

Question


Using function syntax with stand alone executables
If I generate a stand alone executable, lets call it myfun.exe, can I call this using the function rather than command syntax? ...

6 years ago | 1 answer | 0

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answer

Question


I have a function that gives two outputs, what is the easiest way to use fzero on only the second output
I have a function [a,b] = fun(x) when I don't want to change the function. I want to find the value of x for which b returns ze...

7 years ago | 2 answers | 0

2

answers

Question


mtimesx crashes when used
After compiling the user submitted function mtimesx <http://www.mathworks.com/matlabcentral/fileexchange/25977-mtimesx-fast-matr...

7 years ago | 1 answer | 0

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answer

Answered
i keep getting this Attempted to access y(1.5); index must be a positive integer or logical. when trying to implement a numerical hybrid scheme involving y(i+1/2) . here's the code so far: the problem is in line36
You can't call an index of an array with non-positive integer arguments. There is no 3/2 th entry of a matrix or vector, that d...

8 years ago | 0

| accepted

Answered
How to solve "Error using ' Transpose on ND array is not defined. Use PERMUTE instead." ?
My guess is that your variable "img" has more than 2 dimensions. Identify which 2 dimensions of "img = imread(str);" are the on...

8 years ago | 0

Question


Controlling output of ode solvers
I am currently running an ODE solver in the form dy = @(t,y) M*y; [tout,y_out] = ode45(dy, trange,yinit); % y_out is...

8 years ago | 0 answers | 0

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Limiting "y" output of ODE solvers
I am currently running an ODE solver in the form dy = @(t,y) M*y; [tout,y_out] = ode45(dy, trange,yinit); ...

8 years ago | 1 answer | 0

1

answer

Question


Strange colorbar ticks, not standard form
I am finding the behaviour of matlab odd when I am making contourf plots. The data I have is low amplitude so typically the dat...

9 years ago | 0 answers | 0

0

answers

Answered
"XXX" requires more input arguments to run
All these answers are basically "give the function default parameters" which is not always a desirable solution. If I accidentl...

9 years ago | 1

Answered
for about three days I have had this error message: Cell contents reference from a non-cell array object.
The problem is likely that one of X or y is not defined as a cell array. Can you put two lines of code before the error which...

9 years ago | 0

Question


1D Convolution over a slice within 2D data
If I have a matrix R which tabulates some function "R(x,y)" and I wish to calculate I(x,y) = int_{-inf}^{inf} dz P(z) R(x+z...

9 years ago | 0 answers | 0

0

answers

Answered
Solving N linear equations for N unknowns using arrays? Is this even possible?
As you have written it, it seems that sigma_a_InstrumentOneWest=sigma_a_InstrumentOneEast and the same for the instrument ...

9 years ago | 0

Question


Changing function logic parameters depending on outputs
If I have a function with 3 output arguments [a,b,c] = fun(x) I want the function only to calculate a,b,c if I actually c...

10 years ago | 1 answer | 0

1

answer

Question


Matlab UI crashes on startup in windows
When I start matlab on windows and don't enter any commands for a minute or so the cursor changes to a resize arrow and the UI n...

10 years ago | 0 answers | 0

0

answers

Question


What does permute actually produce?
Trying some calculations earlier, I have realised permute does not do what I thought it did. To clarify I did this % c...

10 years ago | 1 answer | 0

1

answer

Question


Dynamic scaling of ODEs
When dealing with (linear) ODEs which have a solutions that decay/grow approximately exponentially is there anyway to get the in...

10 years ago | 0 answers | 0

0

answers

Question


updating function list in a script.
As part of some code I am writing I am printing out symbolic variables into a .m file (so that they can be called with d.p. argu...

10 years ago | 1 answer | 1

1

answer

Question


simplifying symbolic expressions with factors of pi
If I have some symbolic expression say FF = besselj(1/2,x) FF = (2^(1/2)*sin(x))/(pi^(1/2)*x^(1/2)) I wish to cancel th...

10 years ago | 1 answer | 0

1

answer

Question


Factorizing an expression into a function of one parameter symbolic toolbox
Say I have some general symbolic expression which is a function of many symbolic variables a,b,c,d,e,f... etc. e.g. FF = cos(a)...

10 years ago | 0 answers | 0

0

answers

Submitted


Express_as_exponential_series
Converts a symbolic expression S to the form S = sum_{k=1}^N c_k exp(b_k*t)

10 years ago | 1 download |

Question


Symbolic expansions, is it possible to express a solution as a series of exponentials
Lets say I have something like f_t = (A*cos(a*t) + B*sin(b*t))*(C*cos(c*t) + D*sin(c*t)), what I would like is something...

10 years ago | 1 answer | 0

1

answer

Question


Simplifying numbers in symbolic function
Upon substituting into a symbolic expression I get very long analytic expressions for numbers, e.g. (2^(1/2)*(3^(1/2)*pi*(5^(...

10 years ago | 1 answer | 0

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