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Matt J


5,037 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
How to run a loop for multiple variations of a variable.
v_d=zeros(50000,4); %<--change t(1)=0; dt=0.001; for i=1:1:50000 t(i+1)=t(i)+dt; u(i+1) = u(i)+ ...

3 hours ago | 0

Answered
FFT of a single sinusoid showing noise ?!
Looks normal to me, too. Aside from the fact that the sinusoid is discrete, it is also a truncated, non-periodic sampling, so th...

4 hours ago | 0

Submitted


gaussfitn
Fit N-dimensional scattered points with Gaussian+constant

4 hours ago | 18 downloads |

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Answered
Finding the adjoint of a Matrix
For numeric matrices, you can use <https://www.mathworks.com/matlabcentral/fileexchange/12692-adjugate-adjoint-of-a-square-matri...

5 hours ago | 0

Answered
Creating a set of equations programmatically
Your code already works fine. Each anonymous function Q{k} will use a different value for k, even if that isn't printed to the s...

7 hours ago | 1

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Answered
How could I randomly split the columns of a matrix into 3 matrices with equal number of columns?
Ar=A(:,randperm(12)); submatrix{1}=Ar(:,1:4); submatrix{2}=Ar(:,5:8); submatrix{3}=Ar(:,9:12);

8 hours ago | 2

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Answered
List all functions needed to run an application
See <https://www.mathworks.com/help/matlab/ref/matlab.codetools.requiredfilesandproducts.html matlab.codetools.requiredFilesAnd...

9 hours ago | 0

Answered
Not understand function/command
It is not a command. |Frames| is the name of a variable which was created in the first line of the code you have posted.

12 hours ago | 0

Answered
Function used in fsolve with array coefficients
You should be passing ai to MyFun. The size of the ai array can be determined inside MyFun, and from that the number of coeffici...

21 hours ago | 0

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Answered
Matrix pre-allocation question
It is true that you have pre-allocated, but (a) you still aren't using that pre-allocated space for anything, and (b) you are st...

3 days ago | 1

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Answered
How can I convert a equation into an character array?
methods(Static) function surfplot(handles,X,Y,fun) %<---change s=surf(X,Y,fun(X,Y)); s...

3 days ago | 2

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Answered
Faster approach of LU decomposition for a symmetric sparse matrix than lu in Matlab?
Is the matrix positive definite? If so, maybe CHOL?

3 days ago | 0

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Answered
Faster inverse of a lower triangular matrix than inv(A)?
*The reason I want to obtain the inverse of A is that I need to select a number of rows from inv(A) for further uses. I do not j...

3 days ago | 0

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Answered
Getting rank deficient warning when performing linear regression on overdetermined system.
I recommend trying polyfit with centering and scaling, [line1,S,mu] = polyfit(pps1_adj(:,1),time1_adj,1)

3 days ago | 0

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Answered
Specifying page dimensions in pagefun()
PAGEFUN always extracts pages by indexing the 3rd dimension. In other words the |i|-th page is always obtained as if by doing ...

3 days ago | 2

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Answered
Bounding box around image
This might be a useful alternative, <https://www.mathworks.com/matlabcentral/fileexchange/21005-draw-a-border-around-an-image...

4 days ago | 0

Answered
Compare single element common at same indices in 2 matrixes and change values in third matrix
condition = (hValue == 0 & sValue == 0) | (hValue == 0.6 & sValue == 1); vValue(~condition) = 0.5;

4 days ago | 0

Answered
How to set my wave to 0 when >1 and <-1
x = sqrt(2)*cos(pi/2*t); x( abs(t)>1 ) =0 ;

4 days ago | 0

Answered
Constrained minimization where one variable has to be bigger than another
Yes, you use the A,b inputs A=[-1,1]; b=0;

5 days ago | 0

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Answered
Problem in GA algorithm (objective function is not drectly related to the variables)
You have called the function |damage_ele_1| with two arguments |kk| and 1 in the line if e == damage_ele_1(kk,1) However...

5 days ago | 0

Answered
How do I create a structuring element of my own?
Elements outside the boundary of the matrix do not participate in the erosion/dilation. If you pad |aa| to a larger size, you wi...

5 days ago | 0

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Answered
Finding a parabolic function having two known points and curve shape
p=polyfit([2-n, 1,n], [0, .03,0] ,2); y=polyval(p,1:n)

5 days ago | 0

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Answered
suppress output in command window from eval function
You have to put the semicolon _inside_ the command string, e.g., >> eval('a=75;') %No output Not this, >> eval(...

5 days ago | 0

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Answered
Repeat and shift array elementwise
b=cumsum(t); adelta=[0,ones(1, b(end)-1 )]; adelta(b(1:end-1)+1)=-t(1:end-1)+1; ashift=repelem(a,t) + ...

5 days ago | 0

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Answered
Splitting a matrix into group based into the first column and select the maximum value from the second column for each interval
You could use MAT2TILES <https://www.mathworks.com/matlabcentral/fileexchange/35085-mat2tiles-divide-array-into-equal-sized-sub-...

5 days ago | 0

Answered
How to use matlab to draw cubes?
Use the <https://www.mathworks.com/help/matlab/ref/patch.html |patch| command> to draw the faces of the cubes.

5 days ago | 0

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Answered
Solve nonlinear equations within range
syms x y assume(x>=-1 & x<=1) f1 = x^2 + y^2 + x == 4 f2 = x^3 + y*2 == 2 [solx,soly]=vpasolve(f1,f2,x,y)

5 days ago | 1

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Answered
How can I change the color and border of my bars on a hbar graph?
If Years1 is an Mx3 matrix, then you should automatically be getting 3 different colors already. Regardless, you can take contro...

5 days ago | 0

Answered
Is it possible to calculate the line of sight between two points in a 2d polygon?
I'm not sure if it would meet your needs speed-wise, but another option would be to use |intersectionHull| in <https://www.mathw...

5 days ago | 0

Answered
How to apply function in vector form variable?
You should be using logical indexing expressions, like in the following. function S = function_1(T) S=nan(size(T))...

6 days ago | 0

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