# Matt J

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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**Content Feed**

Solve for A matrix in Ax = 0

n=numel(x); mask=tril(triu(ones(n),-1),+1); %tridiagonal mask A=optimvar('A',[n,n]); prob = eqnproblem; prob.Equation...

ongeveer 4 uur ago | 0

negative value structural similarity index

A negative SSIM value means the values in those regions tend to be negatively correlated. When X goes low, then Y tends to go hi...

1 dag ago | 0

How to handle imagedatastore when input and response have different dimension?

Modify the trntf_input, trntf_label datastores' ReadFcn so that when it reads in the image, it wraps it in a 1x1 cell array. S...

1 dag ago | 0

| accepted

How to plot 3D plane of surface with 3 coordinates data?

You can use planarFit, from this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-tools...

1 dag ago | 1

Cure fitting - lsqnonlin

I initially inputted my guess, lower bound, and upper bound with the true optimized values obtained from a published paper. Surp...

1 dag ago | 1

What would be the equation of the following surface?

You could try fitting a 2D Gaussian surface to it, e.g., with this FEX download, https://www.mathworks.com/matlabcentral/fileex...

1 dag ago | 0

Finding Transformation Matrix of a viewer3d object

I think the 3x4 camera projection matrix P would be, h=gca(); camz=h.CameraTarget-h.CameraPosition; camy=-h.CameraUpVector; ...

2 dagen ago | 1

| accepted

Uploading .mat files that contain nested structs into a datastore

This example shows how to use a fileDataStore to read partial data from a .mat file https://www.mathworks.com/help/matlab/ref/m...

2 dagen ago | 0

Which optimization tool should be used for solving my convex optimization problem?

If, as you seem to, you have a non-quadratic (and therefore also nonlinear) convex objective function, then you must use fmincon...

2 dagen ago | 0

Fixed-distance of legend outside plot axes

is there any "simple" parameter (i.e., not position) which controls the vertical distance between the legend box and the upper e...

2 dagen ago | 1

| accepted

the arc using the chord

Assume the chord is of length L and, with no loss of generality, assume also that it is aligned with the x-axis with end points ...

2 dagen ago | 1

Dot Multiplication in MATLAB

For matrices A and B, the rule is generally that A.* B is element-by-element multiplication a(i,j).*b(i,j), which means that nor...

3 dagen ago | 1

| accepted

Find paths in graph that satisfy specific condition

s=[17,17,17,18,18,19,19,20,20,21,21,22,22,23,23,24,24,25,25,26,26,27,27,28,28,29,29,30,30]; t=[18,19,20,21,22,23,24,25,26,27,28...

3 dagen ago | 0

| accepted

Getting error in fmincon with below code how to correct it

You seem to be trying to minimize over a space of functionals, F. You cannot do that with fmincon. The objective must be a funct...

3 dagen ago | 0

How to plot a grouped bar chart?

https://www.mathworks.com/help/matlab/ref/bar.html#bthxce9

3 dagen ago | 0

Subdivide a figure with a grid (as in Timescope)

Something like this, perhaps? t=tiledlayout(2,2); for i=1:4, nexttile(t), plot(rand(1,4)); grid on; end background=axes('Po...

3 dagen ago | 0

vectorized operations on symbolic functions

syms x1 x2 x3; % symbolic variables y = x1^3/3 + x2^2/2 - x3; % symbolic function y X = rand(500,3); % each row representing a...

3 dagen ago | 1

How to add an image to the current axes without replacing existing plots

You can use hold fcontour(@(x,y) (x-50).^2+(y-50).^2,[20,80],'m'); hold on imshow(imread('cameraman.tif')); hold off h=gc...

4 dagen ago | 0

Restart Fmincon Optimization from Checkpoint File

No, unfortunately. Restarting from the last point is probably the best you can do. Although, apart from the interior-point algor...

4 dagen ago | 0

| accepted

Image semantic segmentation dimension layer why not match input and output

Below is what analyzeNetwork gives. Only you know what you want the dimensions of each of your activation maps to be. Tell us at...

4 dagen ago | 0

Combining two arrays using a seconds order

number = randperm(10, 10) number2 = randperm(10, 10) I=ismember(number2,number(1:5)); number(1:5)=number2(I)

4 dagen ago | 0

| accepted

How can I calculate the unique centroids along with its radius range ?

load data; threshold=2; %Example input T=sortrows(table(Centroid, Radius),2) Centroid=T.Centroid; Radius=T.Radius; D=pdi...

4 dagen ago | 1

| accepted

Profile and debug load function

You could pursue your hypothesis by extracting the table from an object, then saving the idnlarx column to its own .mat file. Th...

4 dagen ago | 0

Struct field name with space or special character

Another option is to use dictionaries, which are a bit more similar to structs than tables, e.g. secretID=["Steve Rogers", "Ton...

5 dagen ago | 1

How do I mark all critical points on a graph of a function?

syms x; f=(sin(x)+(1/3)*(cos(5*x))); v=matlabFunction( diff(f) ); f=matlabFunction(f); x=linspace(0,2*pi,1e5); loc=find(g...

5 dagen ago | 1

| accepted

How do I add transparency to a plot in the Live Editor?

The syntax of giving an RGBA color setting seems to be a very old and undocumented feature, https://undocumentedmatlab.com/arti...

5 dagen ago | 1

Question

Plotting lines with quadruplets R-G-B-Alpha ?

It appears that in recent Matlab, I am able to append a 4th number to the RGB triplet, which appears to set either a transparenc...

5 dagen ago | 2 answers | 0

### 2

answersidentifying and isolating consecutive numbers

code that will split A into B = [1 2 3 4] C = [14 15] D = [23 24 25] It would be a bad idea to split A into separate variables,...

6 dagen ago | 1

| accepted

Modifying the objective function in order to meet the optimization variable boundaries

If the boundaries are given by simple lower and upper bound vectors lb and ub, you can do, function fun=objective(A,lb,ub) ...

6 dagen ago | 0

Question

Where is dlfeval tracing information stored?

When dlfeval() is used to call a function, the computation is traced in such a way as to later allow automatic differentiation v...

6 dagen ago | 1 answer | 0