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Matt J


Last seen: Today
6.641 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
How to upsample a 3d point cloud?
Perhaps this is what you are trying to do, [x1,y1,z1] = sphere(24); %Given points (example) x1 = x1(:); y1 = y1(:); z1 = z1(...

alrededor de 13 horas ago | 1

| accepted

Answered
Tools used for Sparse Matrix Efficiency
Do not update the matrix A iteratively inside a for-loop. Just save the coordinate pairs and then use them after the loop to bui...

alrededor de 14 horas ago | 1

Answered
Maximum likelihood Garch with fmincon
Check log_lk_GARCH11VIX(theta). It is returning a bad value.

1 día ago | 0

Answered
Rearranging rows of a boolean matrix so that the diagonals are all non-zero if possible
When your version works, it often works faster than the version below, however your version doesn't always get it right. I've at...

1 día ago | 0

Answered
How can I improve the accuracy of identifying local maxima
I don't think you have any hope of perfect recognition, but this result looks better to my non-clinical eye. A=rgb2gray(imread(...

1 día ago | 0

Answered
how to save file with the given size
This looks like it covers what you're looking for, https://www.mathworks.com/help/matlab/creating_plots/save-figure-at-specific...

1 día ago | 0

| accepted

Submitted


group1s
Assign numerical labels to groups of ones in a binary vector

1 día ago | 1 download |

Answered
Error using extractfield in app designer
The error message has told you that rmdData, as fed to extractfield, is not a struct. You should check what it actually is, and...

1 día ago | 0

Answered
Abrupt changes in data; 'ischange', means, and 'stairs'
Here is a method using the Image Processing Toolbox (treating the signal as a 1D image, in other words). load('dataTest.mat') ...

1 día ago | 0

| accepted

Answered
Fuctions: Multiple inputs & outputs with if statements
No reason at all. And I don't see any disagreement: K>> [krw,kro] = rel_perm(1,1,1,1,1,1,1,1) krw = 0 kro = ...

2 días ago | 0

| accepted

Answered
can you solve the system below?
Yes, you can, e.g., https://www.mathworks.com/help/matlab/ref/linsolve.html

2 días ago | 0

Answered
Why do I get different values when I run gamultiobj for my curve-fitting problem?
I'm not sure why you thought gamultiobj was appropriate for this. gamultiobj is a multi-objective optimizer and therefore will r...

2 días ago | 0

Answered
Importing struct into app designer
The fieldnames command https://www.mathworks.com/help/matlab/ref/fieldnames.html Or, you could just do mergetable1=struct2tab...

2 días ago | 0

Answered
Abrupt changes in data; 'ischange', means, and 'stairs'
Yes, you can use splitapply(@mean,data,G) https://www.mathworks.com/help/matlab/ref/splitapply.html with G identifying the reg...

2 días ago | 0

Answered
Error "Index in position 1 exceeds array bounds (must not exceed 1)" for a matrix that has a size of 2000x11
I am getting the error as listed in the title for line 68 C(i,j)=(-lamda(i,j)+4*A(i,j)/3)/(Kl+4*G(i,j)/3); of the following co...

3 días ago | 0

Answered
Z translate 3D matrix data
One way, [m,n,p]=size(M); [I,J,K]=ndgrid(1:m,1:n,1:p); Knew=K+T; result = accumarray([I(:),J(:),Knew(:)],M(:)),

3 días ago | 0

Answered
Unable to perform assignment because the size of the left side is 2-by-1 and the size of the right side is 1-by-3.
This error message results from doing something like this: >> x=rand(2,3); >> x(:,1)=[4,5,6] Unable to perform assignment bec...

3 días ago | 0

Answered
Lable dimensions of multidimensional array
There is no quick way to enable this, I'm afraid. You would have too write your own customized data object type and provide a su...

3 días ago | 0

Answered
Operator '.*' is not supported for operands of type 'cell'.
Well, you need to check whether B is a cell array or not (it almost certainly is). Did your call to cell2mat work?

3 días ago | 0

Answered
How to display fmincon output outside the command windows ? (Deported output)
The way to gain access to status information during the execution of fmincon is by using the OutputFcn option, https://www.math...

4 días ago | 1

| accepted

Answered
How to create a cell array with the content of a component of a structure?
It is not working because in your for-loop, yourcell is never indexed by the loop variable i, so the loop code has no idea where...

4 días ago | 1

| accepted

Answered
Identify the minimum number of rows in a matrix meeting a condition
This solution uses the Optimization Toolbox, although I am still only half certain what row-selection rule you are looking for ...

4 días ago | 1

| accepted

Answered
Find max/min level of all intersections of a given contour curve with another set of contour curves
A method more along the lines of what you outlined in your initial post, is to put the x,y pairs of the i-th level set of A into...

5 días ago | 0

Answered
Find max/min level of all intersections of a given contour curve with another set of contour curves
The problem you describe cannot be well-defined in terms of discrete contour samples, because there are infinite choices of func...

5 días ago | 0

Answered
fmincon error in intial value
You must do something that not only gets rid of complex-valued results, but also respects fmincon's requirement that your object...

5 días ago | 0

Answered
Creating 3x201 matrix from set of numbers
I=(0:0.1e-10:20e-10).' *[1,1,1];

5 días ago | 1

Answered
how can i get the intersection of two step curves?
I have never heard the terminology "step curve", but see if one of these FEX submissions is useful to you, https://www.mathwork...

6 días ago | 0

Answered
Integral boundaries for a triangular plane
Here is an example from the documentation for integral2 of an integral over a triangular region: https://www.mathworks.com/help...

6 días ago | 0

Answered
Why does Multistart give a output same as the initial guess value?
I am sure the initial guess value (X0) do not give a global minimum. What have you done to verify that? Have you tested optimi...

6 días ago | 0

Answered
Export_fig - Ghostscript program not found
It probably doesn't matter unless you are going to try to export .eps or .epsc files. If you are, you should indeed install Ghos...

6 días ago | 0

| accepted

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