# 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**7**

of 242,536

REPUTATION**20,848**

CONTRIBUTIONS

**193** Questions

**8,212** Answers

ANSWER ACCEPTANCE **
75.65%
**

VOTES RECEIVED**2,793**

RANK**263** of 16,997

REPUTATION**5,174**

AVERAGE RATING**4.90**

CONTRIBUTIONS**33** Files

DOWNLOADS **295**

ALL TIME DOWNLOADS**43649**

CONTRIBUTIONS**0 Posts**

CONTRIBUTIONS**0** Public Channels

AVERAGE RATING

CONTRIBUTIONS**0** Highlights

AVERAGE NO. OF LIKES

**Content Feed**

what changes should i make in final optimised value with opt time vector

Use prob2struct s=prob2struct(prob); s.f0 The value of s.f0 will be the discrepancy between a problem-based linear optimizati...

3 hours ago | 0

fminunc giving correct optimized values for anonymously defined function, BUT wrong value for .m function

At same initial values in two cases (anonymous function and .m function) the objective function gives same values which means th...

6 hours ago | 0

How do I create a matrix that has as values the averages of variables found in loops?

If that's all you want to do, you shouldn't be saving the coordinates of the ROIs. You should just create a binary mask BW of ea...

1 day ago | 1

| accepted

How to assign a specific values to the nearest X,Y point

V=interp2(LON,LAT,SSP,X,Y,'nearest'); See also griddedInterpolant.

2 days ago | 0

I am trying to compute the zero of a function using fzero, but the system always says my function must be finite and real. How can I solve that? Thank you!

Clearly, your function is non-finite at x=0. There is a factor of x^2 in its denominator. Regardless, fzero() is the wrong too...

3 days ago | 0

| accepted

Loop in a cell array that consist of matrices in each cell

Easier: results=cat(3,results{:}); max_column = squeeze( max(results(2:end,12,:)) )

3 days ago | 0

Loop in a cell array that consist of matrices in each cell

You have a variable called "max" previously defined in your workspace.

3 days ago | 0

I would like a function to remove the duplicate values, but one that removes the duplicate value as well.

USing the functions in https://www.mathworks.com/matlabcentral/fileexchange/78008-tools-for-processing-consecutive-repetitions-...

3 days ago | 0

| accepted

fminunc crashes matlab if large number of input variables used

Well, the practice you have of cumulatively nesting anonymous functions inside one another is asking for trouble. You should at ...

3 days ago | 1

| accepted

How to apply logical matrix to the matrix with array operation?

Matrix = [ 3 4; 5 6]; Logical= [ 1 1 ; 0 0]; R=Logical.*Matrix

3 days ago | 0

| accepted

How to substitute one value in vector by vector?

x=[-1 1 -1 1]; X=kron(-x,[1,2,3]); X=X+4*(X<0)

3 days ago | 0

How to substitute one value in vector by vector?

x=[-1 1 -1 1]; x=strrep(10*x,10,[3,2,1]); x=strrep(x,-10,[1,2,3])

3 days ago | 0

why the caculation results is different for parfor-loop and for-loop?

Probably because, with a parpool active, the matrix multiplication code cannot multithread the operation in precisely the same w...

3 days ago | 0

Is there any exmaple on how to apply fmincon function to a state space optimisation problem?

These should be applicable, https://www.mathworks.com/help/optim/ug/fit-ode-problem-based-least-squares.html https://www.mathw...

4 days ago | 0

How to substitute one value in vector by vector?

x=[-1 1 -1 1]; i=(x+3)/2; V=[1 2 3;3 2 1].'; X=reshape( V(:,i) ,1,[])

4 days ago | 0

How to substitute one value in vector by vector?

x=[-1 1 -1 1]; idx=(x==1); X=nan(3,numel(x)); X(1,idx)=3; X(2,idx)=2; X(3,idx)=1; X(:,~idx)=4-X(:,idx); X=X(:)....

4 days ago | 0

Calculation of Hessian matrix in gamultiobj hybrid function

If you mean that you can't compute the Hessian yourself and wish to do so using finite difference approximations then https://w...

4 days ago | 0

Finding the average of the neighbors of each pixel in an image

mean4=conv2(image,[0 1 0; 1 1 1; 0 1 0]/5,'same'); mean8=conv2(image,ones(3)/9,'same');

4 days ago | 1

Issue while fitting semi-circle on a set of points

See incircle() in https://www.mathworks.com/matlabcentral/fileexchange/34767-a-suite-of-minimal-bounding-objects?s_tid=srchtitl...

4 days ago | 0

Issue while fitting semi-circle on a set of points

I recommend circularFit from https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-tools-for-fitting-conic...

4 days ago | 0

| accepted

Using a loop to impose specific values

For example, x=linspace(-1,1,1000); plot(x,twoparts(x)) function y=twoparts(x) y=abs(x); region=x>0; y(region)=x...

4 days ago | 0

combining results into a single matrix

One way. h = [1 2 3 4 5]; n=numel(h); m=n-2; First_Matrix=toeplitz([1,zeros(1,m-1)] ,[1 1 1 zeros(1,n-3)]).*h

5 days ago | 0

| accepted

How do a cell2mat conversion for a non-uniform cell to a matrix

cell2mat(DD(:))

5 days ago | 0

How to make a variable negative if another variable is negative?

X1=X.*sign(Y);

5 days ago | 0

| accepted

Intersection of two lines

You need a least squares solution, since lines in 3D do not generally intersect. Assuming your point data are in column-vector f...

5 days ago | 0

| accepted

Plotting the solutions of an equation (rotated ellipsoid)

If you have the center, radii, and yaw-pitch-roll angles (in degrees) of the ellipsoid, you can plot a data-free ellipsoidalFit ...

5 days ago | 1

Create a 2x3 matrix named mat_B from the first and 2nd rows, and the 2nd, 3rd and 4th columns of the matrix C.

Looks right to me.

6 days ago | 0

| accepted

I dont understand why my table is displaying 1x1 sym and not a numerical value

You seem to be under the impression that vpa() converts a sym to a number. What you really want to do is use matlabFunction() to...

6 days ago | 0

| accepted