Community Profile

photo

Matt J


5.850 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

  • Master
  • Revival Level 4
  • 36 Month Streak
  • Thankful Level 4
  • Knowledgeable Level 4
  • First Answer

View details...

Contributions in
View by

Answered
to find 8 connectivity of an image
https://www.mathworks.com/help/images/ref/bwconncomp.html

etwa 2 Stunden ago | 0

Answered
covariance between the estimated parameters from curve fitting toolbox
There is lsqcurvefit in the Optimization Toolbox. However, the Curve Fitting Toolbox does let you return the Jacobian, which is ...

etwa 4 Stunden ago | 0

| accepted

Answered
fsolve found wrong solution for easy equation
Choosing an initial guess of x=0 in fsolve is often a bad idea because the gradient of the objective will frequently be zero the...

etwa 16 Stunden ago | 1

| accepted

Answered
emptying each row of matrix of a in a loop then uses respective matrices produced from it to get a certain value
Why not as follows, b=nan(size(a,1),1); %pre-allocate for i=1:size(a,1) tmp=a; tmp(i,:)=[], b(i)=...

etwa 21 Stunden ago | 0

Answered
emptying each row of a matrix in a loop
a0=a; for i=1:size(a,1) a=a0; a(i,:)=[], end

etwa 23 Stunden ago | 0

| accepted

Answered
fsolve found wrong solution for easy equation
fzero works better fun=@(x) x^2-1+a/b*log( (b*x^2 -a) / (b-a) ); [sol,fval]= fzero(fun,0) sol = -1.000000128628277 ...

ein Tag ago | 2

Answered
Returning an additional value that is not part of the fitness function or objective for all population evaluation in GA
function run_optimization allSigmas=[]; [xGA,fval] = ga(fun,nvars,[],[],[],[],lowbond,upbond,[],[],options); ...

ein Tag ago | 0

| accepted

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...

2 Tage 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...

2 Tage 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...

2 Tage ago | 0

| accepted

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....

3 Tage 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...

3 Tage 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...

4 Tage ago | 1

| accepted

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...

4 Tage 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...

5 Tage ago | 1

| accepted

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....

5 Tage ago | 0

| accepted

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

7 Tage 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...

7 Tage 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 ...

7 Tage ago | 0

| accepted

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-...

7 Tage ago | 0

| accepted

Answered
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...

7 Tage ago | 1

Answered
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? ...

8 Tage ago | 0

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

9 Tage ago | 0

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

9 Tage ago | 0

Answered
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...

10 Tage ago | 0

| accepted

Answered
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...

12 Tage ago | 1

Answered
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...

12 Tage ago | 0

Answered
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)

12 Tage ago | 0

Answered
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...

15 Tage 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...

15 Tage ago | 0

| accepted

Load more