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Matt J


5,843 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Question


Implicit expansion with empty arrays
I was just idly curious why scalar expansion of an empty array seems to work here (R2018a), >> [1,2,3;4 5 6]-zeros(2,3,0) an...

약 4시간 ago | 1 answer | 1

1

answer

Answered
How to trim segments to fit a square
One solution is to use intersectionHull() from here https://www.mathworks.com/matlabcentral/fileexchange/30892-analyze-n-dimens...

약 4시간 ago | 1

| accepted

Answered
extracting data from struct(structure within a structure)
This may be what you want, targets=[trials.target]; rows=vertcat(targets.row) but it is not very clear from your post how t...

약 12시간 ago | 0

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Answered
ismembertol does not work as documented
The documentation isn't wrong. You've set a tolerance that can only satisfied reliably at A(6) in infinite precision arithmetic....

약 22시간 ago | 0

| accepted

Answered
rotation constraint in imregtform
I don't have a clear picture of the "skips" you are refering to, but it vaguely sounds like it could be addressed by setting the...

1일 ago | 0

Answered
How to speed up function approximation?
There are a few inefficiencies that I see. Firstly, you shouldn't pick an arbitrary StartPoint like [0.8,0.8]. The problem can b...

2일 ago | 1

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Answered
Fit NonLinearLeastSquares to data and constrain curve to pass through point (0,1)
This answer incorporates Torsten's advice, but I also think you should re-formulate the model to make the exponential terms asym...

2일 ago | 0

Answered
Right-truncating a lognormal distribution
I think this is right. How can I code this? function out=conditionalCDF(a,b,x,beta,sigma) pa=normcdf(log(a)-x*beta,0,sig...

3일 ago | 1

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Answered
Coordinate system of matlab
However, i read that Matlab uses two types of coordinate systems which i find really frustrating and confusing at the same time....

3일 ago | 0

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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

5일 ago | 1

| accepted

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...

5일 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 ...

5일 ago | 0

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Answered
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-...

5일 ago | 0

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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...

5일 ago | 1

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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? ...

6일 ago | 0

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

7일 ago | 0

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

7일 ago | 0

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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...

8일 ago | 0

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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...

10일 ago | 1

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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...

10일 ago | 0

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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)

10일 ago | 0

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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...

13일 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...

13일 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...

13일 ago | 0

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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...

23일 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...

23일 ago | 0

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

23일 ago | 0

| accepted

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); ...

23일 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....

23일 ago | 0

Submitted


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

23일 ago | 29 downloads |

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