# 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**

fsolve with two variables in a loop

fun=@(z)[fx(z(1),T(j));fy(z(2),T(j))];

18 hours ago | 0

Receiverd Signal and optimization

w=(hr'*Theta*G +hd')'; w=sqrt(P)*w/norm(w);

1 day ago | 0

Split one table into multiple tables based on multiple variables without reordering.

T=readtable('Data - 2023-01-26_question'); G=findgroups(T(:,1:2)); I=(1:numel(G))'; splitTables = splitapply(@(i){T(i,:)}...

1 day ago | 0

| accepted

Upper bound curve that passes through the extreme (highest) points

load D_by_t_u; load surge_height_1m; final_mat = []; for i = 1:length(surhe_height_1m) if surhe_height_1m(i) > 0.02 ...

1 day ago | 0

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How do I multiply the numbers in a 2D array using a for loop, must be a for loop as part of the course requirements

One way: A3=nan(size(B)); for i=1:size(B,2) A3(:,i)=sind(B(:,i)).^2; end

1 day ago | 0

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How to solve "Conversion to logical from optim.problemdef.OptimizationEquality is not possible." ?

This will solve the "Conversion to logical" error, but not all of the other issues raised by Torsten and me. In particular, Gene...

2 days ago | 0

How to simplify too much of if

FP=[39 45 33 36 27 30, 29,33,24,28,20,24,... 41 46 34,38,29,32,32,36,25,30,22,25,36,49,38,41,31,34,35,39,.... 29,32,24...

2 days ago | 0

Why DerivativeCheck would be allowed to be on while there is no GradObj?

Here's a reason why you might want to allow DerivativeCheck to be on even when the analytical gradient computations are all off....

2 days ago | 0

Why DerivativeCheck would be allowed to be on while there is no GradObj?

So why would MATLAB allow the DerivativeCheck to be on if there is no gradient available? Because maybe SpecifyConstraintGradie...

3 days ago | 0

Effect of zero padding on FFT amplitude

@Rahul Kale It occurs to me now that you are not really trying to compute the Fourier transform of a finite signal. You are inst...

3 days ago | 0

Way to solve AX=XB

[ma,na]=size(A); [mb,nb]=size(B); %size(X)=[na,mb] X=null( kron(speye(mb),A) - kron(B.',speye(na)) ); X=reshape(X,na,mb...

3 days ago | 0

Why DerivativeCheck would be allowed to be on while there is no GradObj?

I would say that no warning is strictly necessary because one of two cases are possible: (1) DerivativeCheck='on' was intention...

3 days ago | 0

How to create a Aij matrix with the commands 'for', 'function output=name_of_code' and 'imagesc'?

m=100; n=150; A=((1:m)'-(1:n)).^2; for i=1:min(m,n) A(i,i)=2*i.^2; end imagesc(A)

4 days ago | 0

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How to create a Aij matrix with the commands 'for', 'function output=name_of_code' and 'imagesc'?

I don't know how to do it and I didn't find any example. Not even here? https://www.mathworks.com/help/matlab/ref/for.html#bu...

4 days ago | 0

Fill in values in function

Z = @(X,Y) (1.5-X+X.*Y).^2 +(2.25-X+X.*(Y.^2)).^2+(2.625-X+X.*(Y).^3).^2; Z(0,0)

4 days ago | 1

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Parallelize nested loops with parfor

Never mind my other answer. I didn't notice that a_sim and h_sim were recursively defined. You can't avoid a loop, but you only ...

4 days ago | 0

Parallelize nested loops with parfor

I don't think it makes sense to use any loops here at all. Just make vectorized calls to your griddedInterpolant objects. [~,~,...

4 days ago | 0

How to interpret actual Camera Intrinsics/Principal Points results?

The uncertainty values look kind of large to me. I wonder if your 22 images are diverse enough.

4 days ago | 0

Extracting two columns from 6-D complex double

T=table((1:numel(val))' , abs(val(:)).^2 )

4 days ago | 0

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Effect of zero padding on FFT amplitude

When zero-padding such a signal one fundamentally change the signal from a constant-valued signal to a square-wave @Bjorn Gus...

4 days ago | 0

How to find the closest values (positive and negative) to the line when X is zero?

load Data %Create line plot [x,is] = sort(V); y = J(is); in=find(x<0,1,'last'); ip=find(x>0,1,'first'); [xn,yn, ...

5 days ago | 0

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Objective function for fmincon from surrogate model

Can't you just do, fun=@(X) norm(mdl.predict(X)-y).^2

5 days ago | 0

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Is it possible to add more constraints than the default ones in LSQLIN function?

You can still use lsqlin, but as John said, you can add additional inequality constraints as follows, Q=-sign(d).*C; r=zeros(s...

5 days ago | 1

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Optimising Limits of Chain integrals

There is virtually no benefit to the problem based approach if you are going to use fminunc. The main advantage of problem-base...

5 days ago | 0

Cross-correlation of two complex signals using sliding dot product

If there is to be no zero-padding, what should happen when the shorter signal slides to the edge of the longer signal? Does the ...

6 days ago | 0

| accepted

Finding Roots between a Differential and Piecewise Equation

a=1; [t_root,fval]=fzero(@(t)rootFcn(t,a), pi) function out=rootFcn(t,a) xp1 =@(t) ((-(8*2)/(2^2+1))*cos(t))+((8/(2^2+...

6 days ago | 0

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Effect of zero padding on FFT amplitude

Here is an example showing that the amplitude of an FFT does not change due to zero-padding. In all cases, the peak amplitude is...

6 days ago | 0

Projection using Modified Gram-Schmidt orthogonality

Aorth=orth(A); %A orthogonalized ProjB=Aorth*(Aorth.'*B); %projection of B

6 days ago | 0

| accepted

How to use conditional bounds for parameters with lsqcurvefit?

You must divide the problem into two cases: one case where X0 is fixed at 0 and the second when Y0 is fixed at zero. xdata = 0:...

6 days ago | 3

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When using JacobianMultiplyFcn in lsqnonlin, why is Jinfo required to be numeric? How can I pass more general kinds of parameters to my JacobianMultiplyFcn?

I seem to be have been able to fool lsqnonlin into doing what I want by using the attached classdef. Still, I wonder why the Opt...

6 days ago | 0