Community Profile # Matt J

Last seen: Today Active since 2009

Professional Interests: medical image processing, optimization algorithms

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How to tell an multi-output anonymous function to vectorize its output components which are constant
One way, f=@(x,y) completeRows({x+y;2;x*y;x.^2-1;3}); f([1 2],3) function out=completeRows(C) n=max(cellfun('length',...

environ une heure ago | 0

Area between three curves
A=Einspeiseanteil; B=GabelstaplerP; C=max(A,B); area=trapz(X,(C-Y).*(C>=Y))

environ 6 heures ago | 0

How to plot vectors exactly on the edge of another graph?
t=linspace(0,360,91); t(end)=0; u=cosd(t); v=sind(t); fimplicit(@(a,b) a.^2+b.^2-1);hold on quiver(u,v,u,v,'Color','r...

environ 23 heures ago | 0

How can I assign values to min/max of a column within each value of another column?
Let's call your table T, then, T=table(randi(2,10,1), randi(100,10,1), rand(10,1),'V',{'Device','Time','current'}) str=[""...

environ 24 heures ago | 0

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min and max optimization as a single minimization function
if i am adding these function together like as follows min(f)=(1/f1)+f2 will it be correct? can i get the proper result? The s...

1 jour ago | 0

4D matrix multiplication
steer=reshape( permute(steer,[2,3,4,1]),101^2,[],136 ); R=permute(R,[2,3,1]); F=1./sum( pagemtimes(steer,R).*steer, 2); ...

1 jour ago | 0

plotting two lines intersecting at a certain point
This is equivalent to a first order free-knot spline fit. This FEX submission might be useful, https://www.mathworks.com/matlab...

1 jour ago | 0

how do you create an array of 3d arrays
I've been trying different ways of using the cat function You haven't told us in what form the 15 stacks exist now. If you have...

1 jour ago | 0

How to grow a vector in a loop?
coef=nan((ldiv+1)^2*(sdiv+1)^2,1); %PRE-ALLOCATE mm=0; for ii = 1:ldiv+1 for jj = 1:sdiv+1 ... ...

1 jour ago | 0

Frequency Domain Filtering by Convolution Theorem
They are warnings, not errors, but if you expect your FFT/IFFT to be real-valued due to symmetry, you can do h2 = ifft2(h1,'sym...

1 jour ago | 1

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How to grow a vector in a loop?
You could just vectorize everything. x_m = [sb_panel.xm]; y_m = [sb_panel.ym]; z_m = [sb_panel.zm]; ...

1 jour ago | 1

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Efficient computation of the sum of pairwise absolute differences
This GPU implementation may also be useful. I was able to process a 500x500 matrix in 20 seconds on the GTX 1080 Ti. A = magi...

2 jours ago | 0

Efficient computation of the sum of pairwise absolute differences
I think parallelization might be the only way to accelerate things. Parfor seems to work well with the rewritten version of diff...

2 jours ago | 1

Efficient computation of the sum of pairwise absolute differences
The question: is there any way to make this work efficiently, ideally with conv2 or xcorr2? If you were taking the sum of squa...

2 jours ago | 0

Matrix-vector operations without loops

2 jours ago | 0

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Linear fitting with 2 variables
Assuming f is 3x1, x=rand(1,15); %Example data f=rand(3,1); y=3*x+2+7*f; [F,X]=ndgrid(f,x); p=num2cell( [X(:), X(:).^0...

2 jours ago | 1

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I want to implement these equations in MATLAB but how?
fn=@(theta,k) exp((0:k-1).' * (2i*pi*d/lambda*sin(theta))); A=fn(theta,M); B=fn(theta,N); y=reshape( A*B.', [],1);

2 jours ago | 0

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How to get the camera scale factor
To get that, you need to image an object of known length at some known reference depth from the camera. You would also need to k...

2 jours ago | 0

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solution of transcedental equation
eps1 = 1.5471; eps2 = 1.5431; eps1m = -9.894 ; eps2m = 1.0458; epsm = eps1m + i*eps2m; lambda = 633; k0 = (2*pi)/lambda;...

3 jours ago | 0

Calculate the Median of the results from 100 Simulations
impOOB=rand(100,5) median(impOOB,1)

3 jours ago | 0

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how to plot inequality and their intersection ?
The region prescribed by your inequalities is unbounded, so it is not clear what it means to "plot" it. If you really meant x<=2...

3 jours ago | 0

How to rotate a 2d plot about the z axis to create a 3d object
See the cylinder command. https://www.mathworks.com/help/matlab/ref/cylinder.html t = 0:pi/10:2*pi; r = 2 + cos(t); [X,Y,Z]...

3 jours ago | 0

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Randomly selecting a number from different arrays
A = [11 11 11 12 12 12 13 13]; B = [21 21 21 22 22 22 23 23]; C = [31 31 31 32 32 32 33 33]; M=[A;B;C]; I=mod(cumsum(ran...

3 jours ago | 0

How solve an equation in MATLAB?
c=A\y;

3 jours ago | 0

fmincon and the Objective function returned NaN warning
The sqp algorithm can recover from NaNs and Infs if your objective and constraint functions are finite on an open domain of x (I...

3 jours ago | 0

Could you please help me to fit 2 circles so as to detect left and right half of breast?
Seems to me that you don't need to fit a circle, but rather to find the minimum bounding circle. For that, you could try minboun...

3 jours ago | 1

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The longest consecutive values in a vector and the position at which it starts and ends
Using "Tools for Processing Consecutive Repetitions in Vectors", https://www.mathworks.com/matlabcentral/fileexchange/78008-too...

3 jours ago | 0

Randomising a vector with respect to the probability of the outcome
I=randi(5,1,12); J=1:12; result=reshape( sparse(I,J,1,5,12) ,[],1); full(result(:))

3 jours ago | 0