Matt J
Professional Interests: medical image processing, optimization algorithms
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Content Feed
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...
ungefär 17 timmar 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=[""...
ungefär 18 timmar ago | 0
| accepted
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...
ungefär 20 timmar 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); ...
en dag 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...
en dag 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...
en dag 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 ... ...
en dag 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...
en dag ago | 1
| accepted
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]; ...
en dag ago | 1
| accepted
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...
en dag 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...
en dag 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...
en dag ago | 0
Matrix-vector operations without loops
A=2*(HessW(:,:)*GradW(:));
2 dagar ago | 0
| accepted
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 dagar ago | 1
| accepted
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 dagar ago | 0
| accepted
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 dagar ago | 0
| accepted
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;...
2 dagar ago | 0
Calculate the Median of the results from 100 Simulations
impOOB=rand(100,5) median(impOOB,1)
3 dagar ago | 0
| accepted
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 dagar 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 dagar ago | 0
| accepted
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 dagar 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 dagar 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 dagar ago | 1
| accepted
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 dagar 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 dagar ago | 0
Creating artificial pictures based on an original picture
Sounds like a job for a GAN, https://www.mathworks.com/help/deeplearning/ug/train-generative-adversarial-network.html
3 dagar ago | 0
Plot for the following program is not showing up, i am trying to plot value of M1 for given L
M1 needs to be a vector: for L=1:799 if ____ M1(L)=____ elseif ___ M1(L)=____ else M1(L)...
3 dagar ago | 0
Matlab fitting an anonymous function
The difference is that, with an anonymous function, you now have the responsibility of providing the StartPoint for the iterativ...
3 dagar ago | 0
| accepted
How to solve 4 non linear equations with 5 unknowns using least square method
There are probably going to be infinite solutions, but you can use fsolve() to find one of them.
4 dagar ago | 0
