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Matt J


Last seen: Today
6,304 total contributions since 2009

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
How do you call an inline or anonymous function within cellfun?
I reverted back to the for loop This might be faster than the for-loop, allB=[B{:}]; idx=ismember(allB,A); Blens=cellfun('l...

17 hours ago | 0

Answered
How do you call an inline or anonymous function within cellfun?
But would still like to know how to use anonymous functions within cellfun There's no difference. Since findVal is already a fu...

18 hours ago | 0

Answered
Converged to an infeasible point.
The initial guess you have chosen x0 = [1,1,1,1,1,1,1,1]; seems very arbitrary. You should devise an initial guess more likely...

1 day ago | 0

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Answered
Matrix sequence manipulation for multiple value assignment
e=1:numel(A); lidx= any(idxes(:,1)<=e & e<=idxes(:,2),1); A(lidx)=1;

1 day ago | 0

Answered
Matrix sequence manipulation for multiple value assignment
If the intervals will always be disjoint, A=zeros(20,1); n=numel(A); A(idxes(:,1))=1; A(idxes(:,2)+1)=-1; A=cumsum(A(1:n)...

2 days ago | 0

Answered
Getting the coordinates of vertices of an A4 sheet with coins on it, for its further projective transformation and coin detection
The Computer Vision Toolbox has a few corner point detector apps, https://www.mathworks.com/help/vision/ug/point-feature-types....

2 days ago | 0

Answered
Relocate a value of a vector.
A=[1 2 3 4 5 6 7 8 9 0]; i=2; %position removed j=7; %target position B=A; k=i<j; B(i)=inf; C = [B(1:j+k-1),A(i),...

4 days ago | 2

| accepted

Answered
table less than operator
Are you sure you do not instead want to compare the content of a variable in the table to something?... yes this what I'm trying...

4 days ago | 0

Answered
Why is N not being displayed?
Because the loop condition is never satisfied and therefore nothing within it is ever executed. I think you meant to have, whil...

4 days ago | 0

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Answered
Displaying information about the data set by clicking on its plot and then show a value that is associated with the (x,y) point
.... set(dcm,'UpdateFcn',@(t,e) myupdatefcn(t,e,x,y) ); function txt = myupdatefcn(~,event,xdata,ydata) pos = get(eve...

4 days ago | 0

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Answered
Getting the linear portion of a non-linear curve
I'm not sure why a 2nd derivative test wouldn't have worked, as long as your points are noiseless: i=find( abs(diff(x,2))>somet...

4 days ago | 1

Answered
How to return the smallest vector.
If you "have them" in cell array form, then you could do something like this: >> vectors={[3 4 5],[1,2],[5 6 7 8]} vectors =...

5 days ago | 0

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Answered
a problem with setting fmincon options?
I would guess that you entered your options object as the 9th input argument to fmincon when it really should be the 10th. If yo...

5 days ago | 0

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Answered
set Precision in lsqcurvefit
You cannot do such a thing with lsqcurvefit. What you describe would require that you rewrite your objective function and bounds...

5 days ago | 2

Answered
Delete part of an image
[m,n]=size(oldImage); x=(1:n); y=(1:m).'; mask = (x-innerCenterX).^2+(y-innerCenterY).^2>=innerRadius^2 & ... (x...

5 days ago | 2

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Answered
Find the orientation of the skeletonized image
You can use houghlines to get the endpoints of all the line segments in the image. From that, you can easily calculate their slo...

5 days ago | 0

Answered
Using cell array to define Argument list in function Handle
That is not the right approach. You should be taking advantage of the fact that this is Matlab, and that your variables are allo...

6 days ago | 0

Answered
Divide plane into two separate planes
Let b1 and b2 be basis vectors for the plane and let x0 be a point in the plane. Then, for example, x0(:) + b1(:)*randn(1,N) + ...

6 days ago | 0

Answered
how to plot values that only fall within a range?
KPH_70 = mean(Y(FVY)); yyaxis left plot(X(FVY),Y(FVY)); yyaxis right plot(X(FVY),KPH_70*ones(size(FVY)));

6 days ago | 0

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Answered
How to pass a vector to a function that creates matrix
>> b=[1 2 3]*10; >> T=@(i) [b(i)+9 , 8 ; 8 , 7 ]; >> T(3) ans = 39 8 8 7

6 days ago | 0

Answered
how to calculate direction in rotated coordinate system
Using AxelRot (Download), and assuming all angles are given in radians, [x,y,z] = sph2cart(Azi_Old,Elev_Old,1); P=AxelRot( ...

7 days ago | 0

Answered
How to work with Nelder-Mead algorithm with 7 unknown variables?
You can use fminsearch (an implementation of Nelder-Mead) with any number of variables. However, there is no way to gaurantee th...

7 days ago | 2

Answered
f(x)=sin(x)-x^5=0 providing x is not equals 0 ,function in the interval x [0,3]
>> [x0,fval]=fzero(@(x)sin(x)-x.^5,[0.8,1]) x0 = 0.9610 fval = -1.1102e-16

7 days ago | 0

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Answered
Generating Toeplitz Matrix which Matches the Convolution Shape Same
Using interpMatrix (Download), nH=numel(vH); nX=numel(vX); ic=ceil( (nH+1)/2); mH = interpMatrix(vH,ic , nX,1);

7 days ago | 0

Answered
Generating Toeplitz Matrix which Matches the Convolution Shape Same
I am specifically asking about using the function toeplitz(). If it must be with toeplitz, then: nH=numel(vH); nX=numel(vX); ...

7 days ago | 0

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Answered
Concatenating matrices in a file into another matrix
For example, >> p1=[1,2,3]; p2=[4 5 6]; p3=[7 8 9]; save p p1 p2 p3 >> A=cell2mat(struct2cell(load('p'))) A = 1 ...

7 days ago | 0

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Answered
Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 2.240406e-24.
Even with A\B, you cannot expect reliable behavior with RCOND as small as 2.240406e-24. For all intents and purposes, your mat...

7 days ago | 0

Answered
Fit a conic section without mirror image hyperbola
This approach uses John's fminspleas FEX submission (Download). Although the fit is, technically, a hyperbola, it diverges to a ...

7 days ago | 1

Answered
rotating and saving images to folder: error during loop
The code works fine for me. If I had to guess, I would say it is because you ran the code previously while debugging and never c...

7 days ago | 0

Answered
Defining constraints in the Quadratic Programming
If you have a quadratic function of only 1 unknown variable, it should be possible to find the minimum analytically - no iterati...

7 days ago | 0

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