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Matt J


Last seen: Today
6.371 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
how can i split a 400*400 matrix into smaller one
You could do it as below, with the help of mat2tiles, https://www.mathworks.com/matlabcentral/fileexchange/35085-mat2tiles-div...

ongeveer 11 uur ago | 0

Answered
Custom CUDA kernels and gpuArrays
Have a look at the documentation for CUDAKernel objects https://www.mathworks.com/help/parallel-computing/run-cuda-or-ptx-code-...

1 dag ago | 1

| accepted

Answered
Redistribution of elements of various arrays into a single multidimensional one
I think the loop you've shown would work just fine, but a quicker way would be array2=repelem(reshape(array1,1,1,[]), 200,4);...

1 dag ago | 1

Answered
discrte to softmax : Attempt to grow array along ambiguous dimension
I know its caused becouse target is larger then array but please help how i should change my code to make it work Did you inten...

2 dagen ago | 0

| accepted

Answered
Max of vector in higher dimensional array subject to constraints
N=ndims(A); %A is the given matrix z=size(A,N); idx=reshape(1:z, [ones(1,N-1),z] ) < constraint; %requires R2016b or h...

2 dagen ago | 1

| accepted

Answered
How to generate random integer from 1 to N except some integers in between?
No loops required, N=10; b=3; M=5; %example data list=setdiff(1:N,b); selection=list(randperm(N-1,M)) %result

2 dagen ago | 1

| accepted

Answered
Matrix consisting of sub-elements of another matrix
By indexing,e.g., >> x = [ 1 2 3 4 5 6 7 8 9]*10; >> y=x([1,2,4,5,9]) y = 10 20 40 50 90

2 dagen ago | 0

| accepted

Answered
How to create an object using class name
function newObj = createNewObject(obj) newObj = feval( class(obj) ); end

3 dagen ago | 0

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Answered
Adding just one line in my code slows the GPU.
Pre-allocate on the GPU. Also, pre-compute things on the GPU that are easily vectorized and don't depend on r. R=gpuArray.zeros...

3 dagen ago | 0

Answered
Converting a row to diagonal matrix
Did some guessing as to what you meant, but I think this is what you want: A=tril(true(16),-1); B=double(A); B(A)=rowdata; ...

3 dagen ago | 0

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Answered
Find minimum of a 15x100 and return in a vector of 1x100. is this possible?
The names of the variables you wrote to the table Min_AS,Med_AS,Max_AS are different from the original variable names you show...

3 dagen ago | 0

Answered
Solve equations in a loop with fsolve
Your equations are quadratic and therefore generally have two solutions, s. Fsolve cannot find them both for you. Why aren't you...

3 dagen ago | 0

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Answered
Any idea how to do and represent ttest results on box plot?
Usually, I just overlay them in powerpoint. But if you must automate this, one not too difficult way would be to use the line co...

4 dagen ago | 0

Answered
changing a group of numbers in a vector
As an example, >> cycles=[0,1,0,1,0,1]; %3 cycles >> A=repelem(cycles,3) A = Columns 1 through 16 0 0 ...

5 dagen ago | 0

Answered
How to replace a vector element with a value not equal the other vector values?
function sudokuRow = fillSudokuRow(sudokuRow) idx=(sudokuRow==0); sudokuRow(idx)=func(sudokuRow(~idx)); end

5 dagen ago | 0

Answered
Passing parameter values found in lsqcurvefit to be initial values for parameter estimation in another function
Some possibilities, Combine the code from both fitting steps into a single script. That way you will have direct access to the ...

6 dagen ago | 0

| accepted

Question


Is there a danger in renaming a Matlab install folder
I have Matlab R2019b installed under Windows 10 in the usual place, C:\Program Files\MATLAB\R2019b but I would now like to ren...

6 dagen ago | 2 answers | 1

2

answers

Answered
Speeding up nested for-loops when vectorization seems to fail
Getting rid of repmat (requires R2016b or later) and working with single float precision will get you some speed-up. In doubles...

7 dagen ago | 0

| accepted

Answered
Speeding up nested for-loops when vectorization seems to fail
I tend to think you should be using scatteredInterpolant rather than implementing your own interpolation routine with loops.

7 dagen ago | 0

Answered
lsqcurvefit does not match data
Your model is clearly wrong, assuming that the given data is valid. In your current model, saturation is always 0 when displacem...

8 dagen ago | 0

| accepted

Answered
Row & Column Wise Normalisation
For a non-negative square matrix, the attached article mentions necessary and sufficient conditions (p. 3, Theorem 1) both for t...

8 dagen ago | 2

| accepted

Answered
How to move programmatically existing datatip
Maybe you can use the advice here, https://www.mathworks.com/matlabcentral/answers/100545-how-can-i-programmatically-control-mo...

8 dagen ago | 1

Answered
How to solve Too many input arguments error? Error in Fminsearch (line 200) fv(:,1) = funfcn(x,varargin{:});
This fh handles should be, fh{n}= @(x)vpe(x,p,MSM(:,n),erps(:,n),n);

8 dagen ago | 0

| accepted

Answered
A is a matrix of size 32*32.I want to subtract elements of each 4*4 block of A from their respective 4*4 means
out = blockproc(A,[4 4],@(x)mean(x.data(:))); result = A - repelem( out , 4,4);

9 dagen ago | 0

| accepted

Answered
Reducing repeated elements in an array by a factor
Another method, one which avoids for-loops inherent in cell2mat, V=[1,2,2,2,0,2,2,2,5,5,5,5,5,5,6,6,6]; N=3; X = cumsum...

9 dagen ago | 0

Answered
The support on here is horrible, does anyone have an api for the function calls? I'm tired of searching only to find examples of what I don't need.
Matlab Answers is a discussion forum, not a documentation browser. If you want to find documentation, start here, https://www.m...

10 dagen ago | 2

Answered
How to use fimplicit with a symbolic function
Using matlabFunction, you can derive a non-symbolic version of your circle equation expression from the symbolic version, >> ci...

11 dagen ago | 0

Answered
How can I get the elements from a matrix and use them as the coordinates in another matrix
D = C( sub2ind( size(C), W(:,1:end-1), W(:,2:end) ) ), sum(D,2)

11 dagen ago | 0

| accepted

Answered
A class to simulate missing arguments in function calls
The main drawback is that one must always use myfeval, which is not very readable. Yet another solution, which might address th...

11 dagen ago | 0

Answered
Multiple selection of an array
You can use sepblockfun downloadable from here https://www.mathworks.com/matlabcentral/fileexchange/48089-separable-block-wise-...

11 dagen ago | 0

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