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# Matt J

##### Last seen: Today
6.379 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
Difference between Matrix and array?
Matrices can only be two-dimensional, whereas arrays can have any number of dimensions. The term "page" for the 3rd dimension do...

alrededor de 10 horas ago | 0

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Answered
Problem related to fminbnd
You could plot the function to see how its shape varies with the parameters and to confirm whether fminbnd is giving the correct...

alrededor de 10 horas ago | 0

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Answered
Visualizing 3 dimensional array
You could probably use volumeViewer, https://www.mathworks.com/help/images/explore-3-d-volumetric-data-with-volume-viewer-app.h...

1 día ago | 0

Answered
Calculate mean of every 4 elements in a row for an array
I recommend sepblockfun (Download), result = sepblockfun(yourMatrix,[1,4],'mean');

1 día ago | 0

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Using if and of two columns to find the value in another column
Here, I use T as the name of your table, lookup=abs(T.X-78.5)<=0.5 & abs(T.Y-48.5)<=0.5; T.Value(lookup),

1 día ago | 0

Answered
Same number of Rows and Cols of a matrix (N*N)
validateattributes(A,"numeric",{"square"})

2 días ago | 0

Answered
How do I minimize this code.
A=input('Enter Matrix A: ') B=input('Enter Matrix B: ') C=input('Enter Matrix C: ') n=length(A); Con=cell(1,n); Obs=Co...

2 días ago | 0

Answered
How to do a matrix from vectors
One way, A=cell2mat( cellfun(@single,{time1 time2 Hs_buoy Tm_buoy Dm_buoy},'uni',0) )

2 días ago | 0

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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...

3 días 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-...

4 días ago | 1

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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);...

4 días 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...

5 días ago | 0

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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...

5 días ago | 1

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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

5 días ago | 1

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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

5 días ago | 0

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

5 días 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...

5 días 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; ...

5 días 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...

5 días 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...

5 días 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...

6 días ago | 0

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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 ...

8 días 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

8 días 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 ...

8 días ago | 0

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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...

8 días ago | 2 answers | 1

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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...

9 días ago | 0

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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.

9 días 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...

10 días ago | 0

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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...

10 días ago | 2

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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...

10 días ago | 1

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