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Matt J


Last seen: Today Active since 2009

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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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Answered
Why are the components of the two eigenvectors not continuous and smooth, when the underlying data is continuous and smooth?
Note that eigenvectors are not generally continuous functions of the matrix entries, as shown in this old example from J.W. Give...

ungefär 18 timmar ago | 1

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Answered
How to speed up my code (computing jacobian)
You can use equationsToMatrix to obtain the Jacobian. Depending on what you are doing, you might then convert the matrix to doub...

3 dagar ago | 0

Answered
How to distinguish pressing cancel vs entering an empty string in inputdlg?
However, this does not distinguish between meaningfully enterring an empty string and pressing cancel/x. It should. Hitting ok...

4 dagar ago | 0

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Answered
fminunc limit step size
No, there is no way to limit the stepsize, but you shouldn't be using a random initial point. That is never a good idea.

4 dagar ago | 0

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Answered
How do I remove outliers in data so that vectors are of the same length for plotting?
Perhaps something like this, [Y,discard]=rmoutliers(Y); X(discard)=[];

7 dagar ago | 1

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Answered
inv(A)*B*inv(A) or A\B/A, which is more accurate for a full rank A and half rank B
I tried both inv(A)*B*inv(A) or A\B/A, resulting in very different results for a gradient descent algorithm. From this, it woul...

7 dagar ago | 0

Answered
Accessing data from same variables within different tables in a structural array
fcn=@(p) interp1( p.data.TimeCooling , p .data.TempCore, timepoints(:)); TempCore_Lookups= cell2mat(arrayfun(fcn,p,'un...

8 dagar ago | 0

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Answered
One function is greater than other
Let us reorganize the inequality as, Since log(z)>0 in the given domain of z, this implies which in turn implies that...

8 dagar ago | 0

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Answered
Finding accurate inverse of binary circulant matrix
We don't know what it is that you consider improper about the results of inv(). The test below indicates to me that everything i...

8 dagar ago | 0

Answered
Proving one function is greater than other?
Make the change of variables and rearrange the inequality as, Since is a convex function on such that >0 and , it read...

9 dagar ago | 0

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Answered
Function to trainNetwork returns an unexpected error
Your X_train and y_train data were in some weird format that trainNetwork cannot recognize. Try this instead, Xdata = num2cell(...

10 dagar ago | 0

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Answered
orthogonal projection of 3D nodes onto a 2D plane
You should post questions about a FEX file on the submission's FEX Discussion forum, since only its author is likely to have the...

10 dagar ago | 0

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Answered
Surf on a cylinder
% Step 1: Create the heatmap data % Example heatmap data heatmapData = peaks(50); % Replace this with your actual heatmap dat...

10 dagar ago | 0

Answered
create a 3D smoothing with csaps (or similar)
load curve_1 cc = curve_1; %or curve_2 x = cc(:,1); y = cc(:,2); z = cc(:,3); t=linspace(0,1,height(cc)); tu=linspace(0...

11 dagar ago | 1

Answered
How to train a vector multiple-input multiple-output network
You have only entered one InputDataFormat. The error message is telling you that you need two of them, e.g., options = training...

12 dagar ago | 0

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Answered
Create different interpolation steps in a column
newy=[1:10,12:2:30, 50:50:500]; newdata=interp1(y,data,newy);

14 dagar ago | 0

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Answered
lambda in fmincon Interior-Point Algorithm with Analytic Hessian
How come it is an input to the function hessinterior? Because both x and lambda are computed iteratively. The solver therefore...

14 dagar ago | 0

Answered
Finding the minimum distance between two matrices
See pdist2.

14 dagar ago | 1

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Answered
Fitting a function with constraints
You can use a custom model for each case: ascending: The minimum y-value must be at the first x-value g = fittype( @(a, t, c, ...

14 dagar ago | 0

Answered
Solve ill-conditioned linear systems
Ill-conditioning is a property of the problem, not the method of solution. You cannot overcome it with any particular choice of ...

15 dagar ago | 0

Answered
Calculations for Each Table in a Cell
for i =1:numel(CoPyData) Trial = CoPyData{i}; CoPv_y = diff(Trial.Displacement)./diff(Trial.Time); CoPv = [...

15 dagar ago | 0

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Answered
Change dimension of a structure
s.Height=3600; s.Width=3601;

15 dagar ago | 0

Answered
find the inflection point of a curve 3D (set of nodes) in matlab
You can use csaps to fit a smoothing spline to the points and then fnder to differentiate the curve and observe curvature change...

15 dagar ago | 0

Answered
How to put 3D array data into mesh grid and find grid cell index of a cube enclosing a given point?
It would be much simpler and more efficient to skip the meshgrid altogether and use discretize. i=discretize(px,x); j=discret...

15 dagar ago | 0

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Answered
How to fit polygon to irregular set of points with only vertical and horizontal edges?
You will need to use a Traveling Salesman Problem solver to sort the vertices. There are a number of them on the File Exchange. ...

15 dagar ago | 1

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Answered
Complex value computed by model function, fitting cannot continue. Try using or tightening upper and lower bounds on coefficients.
fminspleas from this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/10093-fminspleas is helpful for these...

15 dagar ago | 0

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Answered
How to find norm of a 3 X 1 matrix if it contains components in parametric form?
syms t coupler_parametric=[5163136522924301/2251799813685248,... 2^(1/2)/2 - (8*t)/(t^2 + 1), - (4*(t^2 - 1))/(t^2 + 1) - ...

16 dagar ago | 1

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Answered
wrong type variable in uitable
"Unrecognized property 'VariableTypes' for class 'matlab.ui.control.Table'." Indeed, there is no such property. Why did you put...

17 dagar ago | 0

Answered
create a 3D average plan (or normal) from two 3D plans (or normals)
There is no universally recognized concept of an "average plane". One definition you could adopt is the plane obtained by fittin...

17 dagar ago | 0

Answered
polynomial multiplication not accurate, using conv() vs symbolic
To avoid the numerical instabilities of high order polynomials, don't work with the coefficients of D4_poly^2. Just evaluate D4_...

18 dagar ago | 0

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