Community Profile

photo

Matt J


6.133 total contributions since 2009

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.

Contact

Matt J's Badges

  • Personal Best Downloads Level 4
  • First Review
  • 5-Star Galaxy Level 5
  • First Submission
  • Master
  • Revival Level 4
  • 36 Month Streak
  • Thankful Level 4
  • Knowledgeable Level 4
  • First Answer

View details...

Contributions in
View by

Answered
Extract submatrix from matrix.
>> S=regionprops(yourMatrix>0,'Image'); >> S.Image ans = 2×2 logical array 1 1 1 1 ans = 2×3 lo...

alrededor de 5 horas ago | 1

Answered
Update graph (Graph Theory)?
Perhaps like this, hold on H = subgraph(G,idx); %new part of graph plot(H,'Layout','force','XData',___, 'YData',_____) ...

alrededor de 6 horas ago | 0

| accepted

Answered
fit options in a parfor loop
A guess as to why this might be happening is that fitoptions objects don't seem to implement proper save/load behavior, as indic...

alrededor de 6 horas ago | 2

Answered
Something strange in MATLAB
Chances are the issue is not in the code, but in the new data that you have supplied as input. For some reason, this input data ...

alrededor de 7 horas ago | 0

Answered
How I do evaluate a function handle in other function handle
I think this line needs to be g=@(x,y) f(x,y)*p_y(f,x,y) + p_x(f,x,y);

alrededor de 7 horas ago | 0

Answered
How to average more than 50 3D matrices using nanmean
Here's what I would do, I suppose. It assumes each of your .mat files stores the volume under the name 'a'. Summation=0; NCoun...

alrededor de 7 horas ago | 2

| accepted

Answered
The best way to code this optimization problem
I have matlab 2013b Because the array sizes are fairly small here, the easiest thing might be to use my func2mat submission to ...

alrededor de 22 horas ago | 0

Answered
Is there any way to fill this shape?
I=imread('shapes.jpg'); % to extract orange color A=(I(:,:,1) >= 245 ) & (I(:,:,1) <= 255) & ... (I(:,:,2) >= 121 ) & (I(:,:...

alrededor de 23 horas ago | 0

| accepted

Answered
How to use options in fsolve
I know that i have to do fsolve(@(x) myfunz,x0,options) I don't think so. The exit message says "Equation solved". Another ...

alrededor de 24 horas ago | 0

Answered
The best way to code this optimization problem
It should be very straightforward using the problem-based solvers in the Optimization Toolbox, https://www.mathworks.com/help/o...

1 día ago | 1

Answered
how do i create a random matrix with set size yet the numbers are in a range from 0-9
randi([0,9],4,6) %random integers or 9*rand(4,6) %non-integers

1 día ago | 0

| accepted

Answered
Error while using blockproc. Matrix dimensions must agree.
Matrix dimensions must agree. Error in dct (line 76) b = W .* fft(y); It would appear that W and y are not the same size....

2 días ago | 1

| accepted

Answered
Form a 3D matrix for a 2d matrix
NewM3D = reshape(ExitVector,size(M3D));

2 días ago | 0

Answered
how can i bound rate of changes (dx/dt) in fmincon optimization?
See https://www.mathworks.com/matlabcentral/answers/490758-limit-on-the-change-rate-of-the-variable-in-fmincon-function#answer_...

2 días ago | 0

Answered
Limit on the change rate of the variable in fmincon function
You would build linear inequality matrices like the following. E=diff(eye(numel(u))); A=[E;-E]; b=[ub(:);-lb(:)]; %linear ...

3 días ago | 1

| accepted

Answered
Multiplication in cell arrays
result = cat(3,precip{:}).*reshape(numbers,1,1,[]); There seems little reason either for precip to be a cell array or to turn t...

3 días ago | 0

Answered
Regular expression for 1*1 cell array
c='<string_attribute name="country"><s>CHINA5</s></string_attribute>'; out=extractBetween(c,'<s>','</s>'); >> out{1} an...

3 días ago | 1

Answered
Weighted fit with lsqcurvefit and (ideally) multistart?
Just apply whatever weights you want to the objective and to your ydata, fun=@(x,xdata)kinetics_full(x,xdata).*sqrt(weights); ...

3 días ago | 0

Answered
Rotate matrix with interp2
This might be what you want. [X,Y]=meshgrid(x-mean(x),y-mean(y));

3 días ago | 0

| accepted

Answered
Finding angle of rotations from a given unit vector to rotate a given vector using those angle to align with the previous unit vector
The following might be what you're looking for. It uses my AxelRot utility from the File Exchange https://www.mathworks.com/mat...

4 días ago | 0

| accepted

Answered
Nested For Loop for 2D Matrix
I vaguely wonder whether you are just re-inventing convolution result = conv2(Matrix,staticMatrix,'valid');

4 días ago | 0

Answered
Nested For Loop for 2D Matrix
So then you want to extract random 51x51 submatrices? If so, then, I=sort(randperm(600,51)); J=sort(randperm(1000,51)); sub...

4 días ago | 0

| accepted

Answered
The result of rotation matrix rotx(angle) with a coordinate does not give the desired result
Here's what my AxelRot utility gives https://www.mathworks.com/matlabcentral/fileexchange/30864-3d-rotation-about-shifted-axis?...

4 días ago | 0

Answered
how can I find the coordinates of the central axis of a river in an image (binary)?
load River C=watershed(bwdist(A))==0; [icoords,jcoords]=find(C); %coordinates of center line imshow(A+C)

4 días ago | 2

| accepted

Answered
Count the number of intersections between any two curves
The only general way (i.e., for arbitrary curves) is using the Symbolic Math Toolbox, solve(curve1==curve2)

4 días ago | 1

Answered
How to match a number between two characters?
>> str=extractBetween("[180] Windabweichung","[","]") str = "180"

4 días ago | 0

| accepted

Answered
How to match a number between two characters?
>> T=regexp('[180] Windabweichung','\[(\d+)\]','tokens'); T{:} ans = 1×1 cell array {'180'}

4 días ago | 0

Answered
Images as the Options in a Drop Down Menu
See here, https://undocumentedmatlab.com/blog/icon-images-in-matlab-uicontrols

5 días ago | 1

Answered
License Manager error -96 (of matlab 2018b)
This may help https://www.mathworks.com/matlabcentral/answers/95122-why-do-i-receive-license-manager-error-96?s_tid=answers_rc1...

7 días ago | 0

Answered
how can i find the stationary points of this equation and find its nature in the region x>0.
You can use diff to get numerical approximations of the derivatives and apply stationary point criteria based on those. If need...

7 días ago | 0

Load more