# 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**

Vectorized solution to replace for loops in nested combinations

Well, you can at least reduce it to 2 loops: T=50; nb2 = zeros( T, 1 ); tic for t = 1:T t1=0:t; ...

ungefär 7 timmar ago | 0

Optimization Curve Fitting: Curves are not converging

One immediate problem that I see is that in sseval, the optimization variables x(i) aren't used at all in the calculation of sse...

ungefär 11 timmar ago | 0

What does this script mean?

It means minimize fun(x) over x for each set of fixed parameters t,c,p,VN. The initial guess for the minimization is g. The mini...

ungefär 11 timmar ago | 0

How to use the Sum function in this instance

Assuming all your variables (x,z,Ar, etc...) are scalars, then, fi=5:85; q1=0.5*cosd(fi).^2; q2=q1+z^2; q3=sqrt(x^2+q2); ...

ungefär 19 timmar ago | 0

Question

Preference settings for command line table display

In R2021b, tables display at the command line as below on the left, whereas in R2022a, it displays as on the right, in a collaps...

en dag ago | 1 answer | 0

### 1

answerHow to select fields of a struct that contains certain string?

load table for i=1:numel(trial_table) s=trial_table(i).trial; [~,loc]=ismember({'1','2'},{s.message}); result(i)...

en dag ago | 0

using lsqcurvefit for fitting the convoluted function to the data set

As a first pass, you should probably approximate the Fermi function by an ideal step function, so that the "convolved Gaussian" ...

2 dagar ago | 1

| accepted

Unable to solve nonlinear equation using fsolve as the message shows No solution found

You haven't shown how the optimization was executed. fsolve appears to work fine below: opt = optimoptions('fsolve', 'FunctionT...

3 dagar ago | 1

How can we find the intersection between two planes in higher dimensions (4d space and above)?

In general, intersections of two hyperplanes would be expressed algebraically by a 2xN set of linear equations Aeq*x=beq. A geom...

3 dagar ago | 1

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How to find the orientation of the line of the intersection between two planes?

P1 =[177668442.453315 ,-102576923.076923, 0]; P2 =[ -102576923.076923 ,177668442.453315 ,-102576923.076923]; P3= [0, -1025769...

4 dagar ago | 1

| accepted

How do I save for loop plots to a figure directory?

One possibility: saveas(gcf, fullfile(OutputFigures, "FIG"+i) );

4 dagar ago | 0

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Why do I get different outputs for fsolve when I use different initial point?

Why do I get different outputs for fsolve when I use different initial point? Because you have local solutions. You need to cho...

4 dagar ago | 0

| accepted

Fminsearch for fitting models (unconstrained nonlinear minimization of rmse)

rmse= sqrt(sum((ydata-(c1./(1+exp(-a1-b1.*xdata))+c2./(1+exp(-a2-b2.*xdata))+d).^2))./numel(xdata));

4 dagar ago | 1

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How can I efficiently use an array of patterns to create figure titles?

One possibility: regNames = ["Anterior HPC" "Posterior HPC" "Amygdala" "Enthorinal Cortex" "Pararhinal cortex"]; pats = "u" + ...

6 dagar ago | 1

2D matrix transformation (Brown-Conrady distortion model) fitting

You can use lsqcurvefit if you have the Optimization Toolbox.

6 dagar ago | 0

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Fzero giving weird answer

As you can see from the plot, the root lies quite close to solution, so fzero succeeded. If this violates your expectations, it ...

6 dagar ago | 0

Question

Why is it forbidden to call a superclass method from a subclass function of a different a name?

I tried the thing in the screenshot below, i.e, to call the super-class method getThis() within the sub-class method someFunc()....

6 dagar ago | 0 answers | 0

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answersHow to find the line of intersection between the following two planes and plot the intersected line on the same two planes?

You can get the line of intersection in Dual Plucker Matrix form as follows: A=null([[P11;P21;P31],ones(3,1)]); %plane 1 B=...

7 dagar ago | 0

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Length of lower bounds is < length(x); filling in missing lower bounds with -Inf. Problem is unbounded

A=readtable('4times6249datacsv'); A=table2array(A); f=sum(A,2); Aeq =ones(1,4); beq = 1; lb = zeros(4,1) ; a = linpro...

7 dagar ago | 0

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Maximization problem in MATLAB Optimisation Toolbox

Will it work same here? Yes. Example: fun=@(x) -x^2; %maximize this xmax=fmincon( @(x) -fun(x) , 1) It worked!! But anoth...

7 dagar ago | 1

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Given a quadrilateral image, not necessarily a rectangle, how to find its top left point's x-y coordinate

You can use pgonCorners from https://www.mathworks.com/matlabcentral/fileexchange/74181-find-vertices-in-image-of-convex-polygo...

7 dagar ago | 0

How to use Matlab Functions with Vector of Structures

m = min([struct.field1])

7 dagar ago | 0

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Defining objective functions appropriately

It depends what environment you are formulating the problem in. fmincon and fminunc will only minimize functions, so you cannot ...

7 dagar ago | 0

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Question

Isn't it dangerous to allow Comma-Separated-List functionality in indexed assignments?

I have a function below called renamefields() which, as the name suggests, renames a desired subset of struct array fields as de...

7 dagar ago | 1 answer | 0

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answerHow to get comlex root of an equation using fminbnd?

fminbnd is for minimzing over a 1D interval. It's not clear to me how you are defining 1D interval bounds for a number that does...

8 dagar ago | 0

Issues in the constraint functions of the Optimization Problem solving

function [c,ceq]= area(x0) M=5; % x0=[5,8]; M2=m(M,x0(1)); M3=m(M2,x0(2)); M4=m(M3,(x0(1)+x0(2))); beta1=b(M,(x0(1)))...

8 dagar ago | 0

collapsing rows of a cell array into a single cell

Data2=num2cell(Data,1); However, I wonder why you would want to do this. Matrices are usually faster to manipulate than cells, ...

9 dagar ago | 0

| accepted