# 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.

**Statistics**

RANK**6**

of 287,357

REPUTATION**30,010**

CONTRIBUTIONS

**252** Questions

**11,531** Answers

ANSWER ACCEPTANCE **
76.98%
**

VOTES RECEIVED**3,975**

RANK**218** of 19,397

REPUTATION**6,282**

AVERAGE RATING**4.90**

CONTRIBUTIONS**36** Files

DOWNLOADS **329**

ALL TIME DOWNLOADS**52796**

RANK

of 140,979

CONTRIBUTIONS

**0** Problems

**0** Solutions

SCORE**0**

NUMBER OF BADGES**0**

CONTRIBUTIONS**0 Posts**

CONTRIBUTIONS**0** Public Channels

AVERAGE RATING

CONTRIBUTIONS**3** Highlights

AVERAGE NO. OF LIKES**2**

**Content Feed**

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; ...

4 hours ago | 0

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...

5 hours 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...

9 hours 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...

12 hours ago | 0

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 ...

13 hours 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...

23 hours ago | 1

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...

1 day ago | 0

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...

1 day ago | 0

How to plot a grouped bar chart?

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

1 day 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...

1 day 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...

1 day 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...

2 days 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...

2 days 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...

2 days 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)

2 days 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...

2 days 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...

2 days 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...

3 days 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...

3 days 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...

3 days 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...

3 days 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,...

4 days 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) ...

4 days 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...

5 days ago | 1 answer | 0

### 1

answer3D image alignment: How to extract rotation angles about "static" x,y,z axes from a 3x3 rotation matrix

Attached is the utility that I use. In alignment with what you are pursuing, the code does assume the rotation matrix is a colum...

5 days ago | 0

Divide circular rings in N angular portions

The problem is that the angular portions do not have the same number of elements That's because the image is discretized into p...

5 days ago | 1

| accepted

Error in table row subscript

In what way is this not what you want? Northpopulation = readtable("LN_NEXTGROWTH.csv"); %LN = []; <-----You don't need this ...

5 days ago | 0

how can I plot a 3-D helical trajectory

t=linspace(0,18*pi, 3000); plot3(2*cos(t), 2*sin(t), t/pi)

5 days ago | 0

How to calculate spray cone angle?

load Image BW = imfill( bwareafilt(imclose(entropyfilt(im2gray(Image))>4.5,strel('disk',5)),1),'holes'); BW=bwareafilt(~im...

6 days ago | 1

Array indices must be positive integers or logical values.

fx = @(X) X.^2-1-sin(X);

6 days ago | 0

| accepted