Matt J

Last seen: Today | Active since 2009

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Professional Interests: medical image processing, optimization algorithms PLEASE NOTE: I do not read email sent through my author page. Please post questions about FEX submissions in their respective Comments section.

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deepNetworkDesigner: autoscrolling, connection preservation, undoing, and landscaping
I am encountering several issues with deepNetworkDesigner. (1) I have a large network whose layers do not fit entirely on one s...

20 hours ago | 0 answers | 0

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I have an equation. I want to adjust one of the values in the equation until it hits a certain output. How do I run a loop to increment that certain value until it does this?
X=21; Y=4; P=3; increment=1; Yp=X/P; delta=ceil((Yp-Y)/increment); Y=Y+delta

1 day ago | 0

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transformPointsForward does not support PolynomialTransformation2D
Polynomial tforms are generally not invertible, so you can only define them in one direction. I assume fitgeotform2d always fits...

3 days ago | 0

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FGETL taking a long time to execute
readlines?

3 days ago | 0

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How to view a 3D Figure from "below", e.g. z-axis facing downwards
Set the CameraUpVector axis property. figure plot3(0,0,0) line([0 0.1],[0 0],[0 0],'LineWidth',5,'DisplayName','X') line([0 ...

3 days ago | 1

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Convert Set of (x,y) Coordinates Into Polygon
This uses tspsearch from the File Exchange, https://www.mathworks.com/matlabcentral/fileexchange/71226-tspsearch load coordina...

3 days ago | 0

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Using drawpoint in 3d axes
Another approach is to make a custom app, with controls for the position of the electron. ...

8 days ago | 0

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Using drawpoint in 3d axes
You cannot place a 3D point using a drawing object that has only 2 degrees of freedom. Probably the better approach is to use th...

9 days ago | 0

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How do I set up fmincon correctly for parallel computation? "Supplied objective function must return a scalar value"
I want to parallelize the computation, either by calculating several gradients at the same time, or solve the problem for severa...

11 days ago | 0

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Multiobjective optimization with polygon boundary
Use vert2lcon to find the inequalities for the constrained region, https://www.mathworks.com/matlabcentral/fileexchange/30892-a...

11 days ago | 1

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Custom loss function (based on error multiplication rather than sum) in classification neural network
Using trainnet you can provide any loss function you wish. However, a multiplicative loss function sounds like a doubtful idea. ...

12 days ago | 0

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Vectorizing 2D DFT for only select region of the output
Ex=subDFTmatrix(kx_vals,Nx); Ey=subDFTmatrix(ky_vals,Ny); F_partial = Ey*image*Ex.'; function E=subDFTmatrix(k,N) E...

13 days ago | 0

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Submitted

N-dimensional sparse arrays
Creates an N-dimensional sparse array object, for arbitrary N.

14 days ago | 20 downloads |

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Where I make a mistake with fminimax?
Some ideas, The choice of initial guess p0=[1,1,1,1,1] looks arbitrary. I don't see why that would be a good guess. You should...

15 days ago | 1

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How to get a dlgradient result for a blackbox function
radon() can be expressed as a matrix multiplication, and matrix multiplications are of course supported by dlarrays. One option ...

15 days ago | 1

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Does gather() clear memory
It seems to for me: >> A=gpuArray.rand(300,300,300); >> gpuDevice().AvailableMemory ans = 3.1956e+09 >> A=gather...

15 days ago | 0

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How to use validation dataset in iteration-based deep network training?
Sure, use the network to make some predictions, https://www.mathworks.com/help/deeplearning/ref/dlnetwork.predict.html

16 days ago | 0

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What are the differences between fitrnet and trainnet?
Unlike fitnrnet, the L-BFGS algorithm used by trainnet does not seem to use a line search. That might have had something to do w...

16 days ago | 0

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A simple question regarding image processing
I see that some pixels are darker than others, but no pixels that are jet black. If you have some criterion to decide which pixe...

16 days ago | 0

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define an objective function with user defined number of variables in fminunc()
The only way fminunc knows the number of variables is by looking at numel(x0) where x0 is the initial guess: xmin = fminunc(fun...

16 days ago | 2

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Deconvolution of two different Gaussians
If you know a priori that all the signals are Gaussians, then deconvolution would not be the best way to recover espread. You kn...

17 days ago | 0

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Displaying a struct containing gpuArray fields takes an extremely long time in R2024b
Here's a possible workaround: c.a=1; c.b=2; c.data=gpuArray.rand(100,100,100,'double'); tic; c, toc c = struct with...

17 days ago | 0

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Finding a circle in a 2D array
load P BW=median(P(:))-P>50; BW=bwpropfilt(bwareaopen(BW,100),'Eccentricity',6,'small'); c=vertcat(regionprops(BW,'Cent...

17 days ago | 1

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imerode/imdilate use convolution?
No, imdilate is a sliding window max() operation, which is nonlinear, and therefore not, in general, a convolution. Similarly im...

18 days ago | 0

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Take 3x3 nearest neighbours round centroids of all spots and find the median of their mean
sz=size(IM); centroidIdx=sub2ind(sz,y1,x1); T=combinations(1:3,1:3); delta=sub2ind(sz,T{:,2},T{:,1})'-(sz(1)+2); resu...

18 days ago | 0

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Answered
Take 3x3 nearest neighbours round centroids of all spots and find the median of their mean
movingMean=conv2(IM,ones(3)/9,'same'); centroidIdx=sub2ind(size(IM),y1,x1); result=median(movingMean(centroidIdx))

18 days ago | 0

Question

Displaying a struct containing gpuArray fields takes an extremely long time in R2024b
I find that when I create a struct (or object) whose fields are large gpuArrays, it takes an extremely long time (1-2 minutes) t...

19 days ago | 2 answers | 0

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Submitted

gaussfitn
Fit N-dimensional scattered points with Gaussian+constant

19 days ago | 20 downloads |

Answered
MINLP problem in MATLAB with both integer constraints and nonlinear equality constraints
If, as @Torsten mentioned, you are in the situation where the equality constraints only depend on the continuous variables, then...

21 days ago | 0

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how to use fmincon to optimize a functio with more than one control vector where the control vectors used in constrains also?
Use the problem-based optimization framework to launch fmincon. It will look approximately like, p=optimvar('p',pi,pj); X=opti...

22 days ago | 0

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