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Matt J


6,180 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
Trying to plot Eulers, but keep getting straight line
You're getting a straight line because the right hand side of this line acmi(1:10001)=-a+(alpha(n)*l*cos(theta(n)))-((omega(n)^...

15 hours ago | 0

Answered
how to write a function for quadratic equation
[x1,x2] = QuadraticEquation (1,-2,0) function [x1,x2] = QuadraticEquation (a,b,c) d=b^2-4*a*c; if d>=0 disp ('...

16 hours ago | 0

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Answered
How to sum a series of numbers?
sum(numerator./denominator)

16 hours ago | 0

Answered
multi-variable optimization in matlab?
Many other variables are to be calculated first, which are actually functions of the first two variables, and then they're used ...

17 hours ago | 0

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Answered
Call a function in a sub directory?
The only way, I believe, is to visit each folder and create a function handle to each respective version of sayhi(), cd folder1...

17 hours ago | 0

Answered
Map a 2D matrix into 3D using loop for allotment along the 3rd dimension
You could try this. clear data_trialwise for i=20:-1:1 data_trialwise(:,:,i)=data(:,begin(i):end(i)); % begin and end bot...

18 hours ago | 0

Answered
shifted triangular matrix array
ac=num2cell([0,0;a],2); T=toeplitz(1:4,[1,zeros(1,3)]); A=cell2mat(ac(T+1)) A = 1 2 0 0 0 ...

21 hours ago | 1

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Answered
How can i multiply cell arrays?
for i=1:2 for j=1:2 H{i,j}=H{i,j}.*X{i}; end end

21 hours ago | 0

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Answered
Most efficient way to enter values into pre-allocated sparse matrix?
I would just store all the data from the loop calculations in cells. Then use the data to build the sparse matrix after the loop...

24 hours ago | 0

Answered
Is possible configure matlab to get a+[ ]=a?
You could also replace your plus() operations with sum() operations. Compare: >> a=3; b=[]; >> a+b ans = [] >>...

3 days ago | 1

Answered
Is possible configure matlab to get a+[ ]=a?
No way that you're going like. You could subclass Matlab's double type https://www.mathworks.com/help/matlab/matlab_oop/extend-...

3 days ago | 1

Answered
Error using griddedInterpolant The grid vectors do not define a grid of points that match the given values.
You have 20 Y samples, but your V has 21 rows. >> whos X Y V Name Size Bytes Class Attributes V ...

3 days ago | 0

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Answered
Average of every nth value in a vector
tmp=conv(yourvector, ones(600,1)/600,'valid'); result=tmp(1:600:end)

3 days ago | 0

Answered
Add two lines to a matrix.
A=A([1;2;3;3;3],:)

4 days ago | 0

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Answered
3-D line of best fit from origin to cloud of data points
The equation is t*u where u is 3D line direction vector obtained by, [V,d]=eig(A.'*A,'vector'); [~,i]=max(d); u=V(:,i); and ...

4 days ago | 0

Answered
Multi-function optimization
You would need something like the following, options=optimoptions(@fminunc,'SpecifyObjectiveGradient', true); allX = fminunc...

4 days ago | 0

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Answered
2D Convex Hull: I can't think of a 'criteria' to filter out the 'wrong' points, please help!
One thing you can also try to do is find where one of the rays from the pivot point lies inside the triangle formed by its two n...

4 days ago | 0

Answered
Radon Transform Documentation Matlab
I understand the Radon Transform get the product between the length(intersection) of each beam through the pixel and the pixel ...

5 days ago | 1

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Why do the values not get added into the array such as [2,3,5,7], but instead they get summed up?
Because you are using '+'. To concatenate, you would do, values = [values, tester];

5 days ago | 0

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Answered
Make squares in image white
imcomplement(A);

5 days ago | 0

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Answered
Cloud of points Convex Hull
See convhull or convhulln https://www.mathworks.com/help/matlab/ref/convhull.html https://www.mathworks.com/help/matlab/ref/co...

5 days ago | 0

Answered
Using one variable containing all name-value pairs for built-in Matlab functions
See inputParser https://www.mathworks.com/help/matlab/ref/inputparser.html which by default will expand structures into Name-V...

5 days ago | 0

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Answered
How can i find a certain vector in a matrix?
[~,loc]=ismember(vector.',Matrix.','rows');

5 days ago | 1

Answered
How to make difference between two cell array?
fun=@(c) num2str(c,'%.20d '); A=cellfun(fun,NS,'uni',0); B=cellfun(fun,setL,'uni',0); [~,ia]=setdiff(A,B); result=NS(ia)...

5 days ago | 0

Answered
Calculate only diagonal elements of multidimensional array product
Since M is small, a for-loop would probably also be fine, [j,k]=sub2ind([M,M],1:M.^2); for i=1:M^2 B(j(i),k(i),:)=B...

5 days ago | 0

Answered
Calculate only diagonal elements of multidimensional array product
Assuming your Matlab version is post-R2016b reuslt = sum(B.*A.',1) Otherwise, assuming your Matlab version is post-R2008 resu...

5 days ago | 0

Answered
Least Square Minimization (Levenberg-Marquant method) of damped oscillation curves
You can use lsqcurvefit with the 'levenberg-marquardt' Algorithm setting https://www.mathworks.com/help/optim/ug/lsqcurvefit.ht...

5 days ago | 0

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Answered
Need help with subspace basis
You could just use orth()

6 days ago | 0

Answered
Phantom Variable within Object Method Calls
You must decide whether you want your classes to be handle classes or value classes. https://www.mathworks.com/help/matlab/matl...

7 days ago | 1

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