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Matt J


5,196 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
Is there a possibility to use 3D sparse matrices on GPU?
There is not. However, with sparse matrices, it would make more sense just to embed your 1000x1000 pages into larger 2D block di...

1 day ago | 2

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Answered
How to store the results of a function using for-loop
T=cell(1,3); for i=1:3 T{i}=P(i)/(x.*y.*z); end

2 days ago | 0

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Answered
GPU arrayfun is so slow, what is going on?
What is the most efficient way to vectorize the above code I would say, as follows, idx_Neighbor=randi([1 N],60,N,'uint8'); ...

2 days ago | 0

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Answered
How to concatenate structs with different fieldnames?
[Object(1:2).Stats]=deal( struct('Var1', [], 'Var2', [])); %first, do this Object(1).Stats.Var1 = 1; Object(1).Stats.Var2 =...

2 days ago | 0

Answered
Rotating and shifting a meshgrid
theta=-10; shift=[1,1]*175.5362; R=[cosd(theta) -sind(theta); sind(theta) cosd(theta)]; szx=size(Xq); X...

2 days ago | 0

Answered
How do I correctly use the Syntax of fmincon?
If you do not have any linear constraints, then just set them empty A=[]; b=[];

3 days ago | 0

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Answered
Multiple Linear Regression function
Why not features\X

3 days ago | 0

Answered
MINIMIZE A FUNCTION WITH CONSTRAINTS
You might consider this modification, function [ DD ] = overall( x ) global par par2 x1=x(1); x2=x(2); x3=x(3); y= pa...

8 days ago | 0

Answered
How to obtain the minimum square full rank sub-matrix in a sparse matrix?
This article may help: Computing the Block Triangular Form of a Sparse Matrix by Alex Pothen and Chin-Ju Fan. They talk about so...

9 days ago | 1

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Answered
How can I define a constraint to my optimization problem?
Aineq=kron(speye(t),d_ik(:).'); bineq=TR; Note also that your call to intlinprog is the wrong syntax. You haven't specified ...

9 days ago | 0

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Answered
Assign vector to 3d matrix
xhatc(:,1,:) = repmat([1;1],1,1,N);

10 days ago | 0

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Answered
Plotting a 3D matrix over time
If your final data set is a 3x3xN array, D, you can reshape and plot it as follows plot( reshape(D,9,N).' ) This will display ...

10 days ago | 0

Answered
Sum specific range of column or row
sum(yourMatrix,2)-yourMatrix(:,1);

10 days ago | 0

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Answered
How to transform a matrix into a 3D array (tensor) ?
A=[1,2;3 4].*reshape([1,10,100], 1,1,[])

10 days ago | 0

Answered
Large Matrices for solving linear systems
values=[-4,1,1,1,1]; A=toeplitz([values(:), zeros(N-numel(values),1) ]);

10 days ago | 0

Answered
how to read number from picture
You can use the OCR command, if you have the appropriate Toolbox(es).

12 days ago | 1

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Answered
I can't find the solution how can i fix this?
You need to distinguish better between the roles of the index i and of the values xr(i) in the code. clear xr i=1; xr(1)=0; ...

13 days ago | 0

Answered
Convert Nested for-Loops to parfor
You can convert the first set of nested loops to a single parfor loop as below. The second set of nested-loops is non-paralleliz...

13 days ago | 0

Answered
Fast methods of solving equations (alternative methods instead of backslash)
Following Christine's suggestion, here is a simple test of slice-wise backslashing between two 512x512x512 arrays. I find it tak...

14 days ago | 0

Question


Separately license additional toolboxes
My institution has a Concurrent Academic license which provides us with Matlab and a certain bundle of toolboxes. I would now li...

14 days ago | 1 answer | 1

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answer

Answered
How can i take specific values from a matrix and put them into another matrix?
Let's say your matrix is A, Matrices=splitapply(@(z){z},A,A(:,2))

14 days ago | 0

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Answered
Help with adding a column with numbers that are repeated to a matrix
Let's say your matrix is A, A(:,2)=mod(0:2169,12)+1;

14 days ago | 0

Answered
OOP: Select Data with conditional
In this scenario, it is better to have a single object whose properties are arrays than an array of objects whose properties are...

14 days ago | 1

Answered
Why are my plot coming out linear when they're supposed to be curves?
Use ./ and .* for component-wise division and multiplication.

15 days ago | 0

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Answered
Can I make this for loop fast?
Here I make occasional use of MAT2TILES (Download), UK=cell2mat( mat2tiles( U_new'*cell2mat(K111(:).') ,[20,200]).' ); KQQ...

15 days ago | 0

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Answered
removing FOR loop to solve Ax=B on multidimensional arrays on GPU
C=pagefun(@mldivide,A,B)

15 days ago | 2

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Answered
How can I write a self scaling function for fmincon ?
fun = @(x) -sum(log(x))

15 days ago | 1

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