# Matt J

Professional Interests: medical image processing, optimization algorithms

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**Content Feed**

How to get optimal linear scaling factor for a set of vectors

I want to determine a linear scale factor for each y_raw? vector, such that the mean squared error (MSE) between the average of ...

3 hours ago | 0

Linear Equations infinite solutions parametric form

x0=pinv(A)*b; B=null(A); sol=@(c)x0+B*c;

7 hours ago | 0

Submitted

Further tools for analyzing objects in N-dimensional images

A collection of tools to supplement bwpropfilt, bwareaopen, and the like.

11 hours ago | 4 downloads |

How can I speed up (or avoid) a comparison in for loop?

You might try bwlareaopenn from this submission https://www.mathworks.com/matlabcentral/fileexchange/90762-further-tools-for-an...

11 hours ago | 1

Solver based optimization passing extra parameters

nonlcon=@(x)constraintFcn(x,aa) See also, Passing Extra Parameters - MATLAB & Simulink

11 hours ago | 0

How to get the file names that start with the same letter in the folder?

For example, s=dir('T*_imag.bin'); fileNames={s([s.isdir]==0).name}

11 hours ago | 0

Matrix form for creation and annihilation operator with spins.

Not sure this will help, but if you can write a function that implements the operator, then his File Exchange offering, https:/...

12 hours ago | 0

What should go in a next-generation MATLAB X?

My wish list: (1) Colon operator produces column vectors, not row vectors: x=1:4 (2) Optimization Toolbox solvers should ha...

12 hours ago | 2

combine different size vectors into one matrix

I will assume you have the vectors in a cell array C={[2 3 4 5]; [4 7 7]; [8 8 7 4 2 5]} Then, you can simply do, z=...

13 hours ago | 0

using fsolve function to solve for 2 unknowns

x0 = [80,110]; [sol, Fsol] = fsolve(@problem_one,x0), function F = problem_one(theta) theta3 = theta(1); theta4 ...

2 days ago | 1

| accepted

fminunc initial point is local minimum, but fminsearch returns reasonable estaimtes

It could happen if your objective function is piece-wise flat (and hence non-differentiable). fminsearch is a derivative-free so...

2 days ago | 0

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How can I obtain the Fourier Transformation as a product of matrices?

N = (0:255).'; X = (2*cos(((15.8*pi)/128)*N)) + (3*sin(((27.3*pi)/128)*N)); F=fft( eye(numel(X)), [],1); fX = fft(X); %...

2 days ago | 0

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Solving non linear equation "Circle" equations

Because you cannot be certain of an exact 3-way (or n-way) intersection, you need to use a numerical least squares solver like f...

2 days ago | 1

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What is the real value of "single(my_variable)"?

So the C code keeps good precission. But, does Matlab? Yes, if by "good precision" you mean up to 7 digits. You can see that ev...

2 days ago | 0

How to define a constat in function handle?

You mean like this? [a,b,c]=deal(3,4,5); f = @(x,y)a*x.^2+b*y+c Or like this? syms x y a b c f(x,y) f(x,y)=a*x.^2+b*y+...

2 days ago | 0

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Steepest descent with exact line search method

n=input("Enter the roll number:"); fobj=@(x) (x(1)-n)^2 + (x(2)-2*n)^2; gradobj=@(x)2*[(x(1)-n), (x(2)-2*n)]; x0=[1 1]; ...

3 days ago | 0

how to develope loop to save the 'n' elements from the vectors

It is not a good idea to store A(i) in separate variables. You should probably just write your equation in terms of vector opera...

3 days ago | 2

Taylor series approximation problem

As an example, syms x T=taylor(exp(-x),x,7,'Order',4) fn=matlabFunction(T) fn(3) You can of course find more examples...

3 days ago | 0

how can I call a class in a gui?

I have defined a class TimeData by a script Don't you mean you defined it in a classdef file? The constructor function for a c...

3 days ago | 0

Trying to supply fsolve with system's Jacobian but receiving error ''check for incorrect argument data type"

It is not clear (from what you posted), why you are using symbolic variable manipulation at all. fsolve is a numerical solver, n...

3 days ago | 0

Rotate Values of Matrix

Use imtranslate() to center the source in the image, then use imrotate() it by the desired angle, then use imtranslate() once mo...

3 days ago | 0

Get the last for digits as the time this message was sent

Is this what you want? str=char( "!AIVDM,1,1,,A,13cut>1001P:3LRGa`P@jip400S<,0*410002" ) str(end-3:end)

3 days ago | 1

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Is it possible to set an upper limit on the step size used by fsolve?

You could try playing with the InitDampling option parameter used by the Levenberg-Marquardt method.

4 days ago | 0

Am I understanding this correctly?

If by "low" you mean zero and by "high" you mean 255, then yes.

4 days ago | 0

Not sure why while loop won't run.

balance(1) = 1000; contribution = 1200; interest = 0.0025; M = 2; % month ticker while balance(end) < 500000 ba...

4 days ago | 2

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How select data just out from a polygon, considering a constraint

borders=[0,0;0,1;1 1;1 0]; p=polyshape(borders); p=blurHull(p,[0.3,0]); p=blurHull(p,[0, 0.1]); isinterior(p,datas) ...

4 days ago | 0

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Creating Matrix Subset automatic.

You should be doing it as follows: S=A([1,4,7],:);

4 days ago | 0

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How can I sort vector according to its index?

[vect,ind]=sort(vect,'descend')

4 days ago | 0

Plotting Phase Plane in Matlab

For example, funx=@(t) c1*exp(-3*t)+c2*exp(-t); funy=@(t) -c1*exp(-3*t); fplot(funx,funy,[0,1]) or t=linspace(0,1,100); ...

5 days ago | 0