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Matt J


5,834 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
How to find the area of the object in the center?
impoly worked pretty well for me. The area in pixels was 1358238 h=impoly(); area=numel(h.createMask) % 1358238

15 hours ago | 1

Answered
Plot feasible region of a high-dimensional linear programming along some dimensions
I tried to use this without success ... which stops with a long error message that I'm struggling to intepret. The error mess...

16 hours ago | 0

Answered
Quadratic Programming (quadprog):
Using your posted A matrix I find that >> cond(H) ans = 7.5703e+18 For numerical purposes, this is a singular matrix ...

17 hours ago | 0

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Increasing the bounds of integration on a strictly positive function decreases the result
A plot of the function reveals highly oscillatory behavior in the interval [-2e-6,0] which then flattens out to zero in [-1,-2e-...

17 hours ago | 0

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Answered
Can multiple classes share external methods without inheritance?
Is it possible to have external methods that multiple classes share? It sounds like the "external methods" you are trying to im...

1 day ago | 0

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How do I help quadprog converge?
Is checking that the constraints are satisfied and the optimality measure is low a good rule of thumb for making this decision? ...

2 days ago | 0

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How to find mean line of the this edge?
Try bwskel

3 days ago | 0

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Insert desired number of spaces in the string contains numerical value
How about txt="0 STR "+1

3 days ago | 0

Answered
Regression of a vector in a optimization problem
As the others have said, all regression routines in the Optimization Toolbox allow you to represent the unknown variable in vect...

4 days ago | 0

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Answered
abstract class with inherite handle class
You cannot create an instance of an abstract class. Also, your constructor expects arguments EEG and INFO, which you have not pr...

6 days ago | 1

Answered
indexing takes a very long time
It takes a long time because every time you execute the line b = A(i:i+10,i+10,:) memory is allocated for b. Instead of itera...

6 days ago | 0

Answered
How to setup gamultiobj to "explore farther" along a specific objective?
Maybe redefine Obj2 so that it jumps from 16.6 to infinity, Obj2 = Obj2-1+1/(Obj2<16.6)

6 days ago | 0

Answered
Loss function in CNN
I expect you might have to feed the hidden layer outputs forward, making them inputs/outputs of your custom output layer. That w...

9 days ago | 0

Answered
How to add an extra column to a 1x1 structure
I can't be sure from your description exactly what you are trying to do, but it sounds like a table might be much better for wha...

9 days ago | 0

Answered
Extracting part of an image
Use impoly instead of drawpolygon. Use the createMask() method of the impoly object h to extract the ROI pixels pixelvalues = y...

9 days ago | 0

Answered
How to find out the cordinates of the intersection point of a line and a surface?
Plug the equation for the line into the equation for the surface and use fzero to find the root. This root will give the locatio...

19 days ago | 1

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Answered
How to make a long equation line more efficient?
I thought this should help because I have hundreds of these instances If the expression came from matlabFunction, be sure you a...

19 days ago | 0

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Finding threshold for skull segmentation of Head CT images
What about multithresh()?

19 days ago | 0

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Answered
"fmincon" optimization with nonlinear constraints: colon error
You are returning a function handle in c_eq, when really you should be evaluating the function at Cpv, c_eq = Anonymous(Cpv); ...

19 days ago | 0

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Answered
Fast 2D distance calculation
If you have the Parallel Computing Toolbox, you can execute the computations on the GPU just by building p1 and pn as gpuArrays....

19 days ago | 0

Submitted


Structure fields to variables
Code writing tool for importing/exporting workspace variables to or from a struct.

19 days ago | 29 downloads |

Answered
Can I Dynamically Overload A Class Method?
You can't dynamically overload a class method, but you can get the same effect by making function handle properties that dictate...

19 days ago | 0

Answered
Division by an OptimizationVariable not supported.
The problem-based solver is largely limited to linear and (in R2019) quadratic programs. If you find yourself computing non-line...

21 days ago | 0

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Answered
How to use Matlab to fill gaps
This might be what you are looking for Mnew=M; [nr,nc]=size(M); xq=(1:nr).'; for i=1:nc m=M(:,i); ...

21 days ago | 1

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Answered
How to use linear interpolation for filling with 3s inside empty spaces in a matrix of os and 3s
One way: result = sqrt(cummax(M,1).*cummax(M,1,'reverse'))

22 days ago | 0

Answered
lsqcurvefit not adjusting some parameters as expected
It helps to pre-normalize your x,y data and to use polyfit to generate a smart initial guess, %data pre-normalization y=y.'/ma...

22 days ago | 0

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Answered
How could you modify this semi-infinite optimization to global optimization using GlobalSearch?
If you could show me how to modify this MathWorks example, then I could modify my scripts. It would look like below, myfun=@(x...

22 days ago | 1

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Question


Set union of Datastores with TransformedDatastores
Given an imageDatastore and some transformation of it, e.g., imds1 = imageDatastore({'street1.jpg','peppers.png'}); imds2 = ...

22 days ago | 1 answer | 1

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answer

Answered
Finding global minimum with fseminf
Is it a good strategy to call fseminf lots of times with different starting values? It's not a bad strategy, but no strategy is...

22 days ago | 0

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Answered
I need to solve four differential equation with four unknown variable simltaneously . how can i do that in matlab?
In all likelihood, your problem description is incomplete. As written currently, the problem has the trivial solution, K1=K2=K3...

23 days ago | 0

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