Professional Interests: medical image processing, optimization algorithms

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Answered

How to make specific elements of a matrix zero before nth element?

[m,n]=size(A); C=A.*((1:m).'>=B);

How to make specific elements of a matrix zero before nth element?

[m,n]=size(A); C=A.*((1:m).'>=B);

1 giorno ago | 2

| accepted

Answered

Trouble with struct indexing?

... to access a single element of field2. The layout of your struct variable is not clear. If, for example, you have a scalar s...

Trouble with struct indexing?

... to access a single element of field2. The layout of your struct variable is not clear. If, for example, you have a scalar s...

1 giorno ago | 0

Answered

Union() operation adds hole to polyshape

https://www.mathworks.com/matlabcentral/answers/518591-union-operation-adds-hole-to-polyshape#comment_834234

Union() operation adds hole to polyshape

https://www.mathworks.com/matlabcentral/answers/518591-union-operation-adds-hole-to-polyshape#comment_834234

1 giorno ago | 0

| accepted

Answered

Approximate a log curve as linear to predict a value

idx=(P<=0.1); c=polyfit(log10(P(idx)),Q_p_1(idx),1); semilogx(P, Q_p_1, P,polyval(c,log10(P)),'x-' )

Approximate a log curve as linear to predict a value

idx=(P<=0.1); c=polyfit(log10(P(idx)),Q_p_1(idx),1); semilogx(P, Q_p_1, P,polyval(c,log10(P)),'x-' )

5 giorni ago | 0

| accepted

Answered

3D Array Rastering

I'm not sure from your description how this should generalize for different N, but perhaps this is what you want: >> N=2; Array...

3D Array Rastering

I'm not sure from your description how this should generalize for different N, but perhaps this is what you want: >> N=2; Array...

5 giorni ago | 0

| accepted

Answered

Using fminsearch I want to plot the model function whose parameters I'm fitting at each iteration without the figure window stealing focus. How do I do this?

Stop invoking whatever command it is (figure(), axes() ?) that you are using to bring the figure into focus. Calling the plot co...

Using fminsearch I want to plot the model function whose parameters I'm fitting at each iteration without the figure window stealing focus. How do I do this?

Stop invoking whatever command it is (figure(), axes() ?) that you are using to bring the figure into focus. Calling the plot co...

6 giorni ago | 0

Answered

Calculation of the gradient of a function in BFGS Quasi-Newton Algorithm

With respect to all the variables that are unknown.

Calculation of the gradient of a function in BFGS Quasi-Newton Algorithm

With respect to all the variables that are unknown.

6 giorni ago | 0

| accepted

Answered

matrix dimensions must agree error

Possibly a missing comma here, K=1/h^2*(2.*diag(ones(1,N+1))-diag(ones(1,N)-1)-diag(ones(1,N),1)); ...

matrix dimensions must agree error

Possibly a missing comma here, K=1/h^2*(2.*diag(ones(1,N+1))-diag(ones(1,N)-1)-diag(ones(1,N),1)); ...

9 giorni ago | 0

| accepted

Answered

Define a variable without assigning a value

Perhaps you are trying to do symbolic computations, https://www.mathworks.com/help/symbolic/performing-symbolic-computations.ht...

Define a variable without assigning a value

Perhaps you are trying to do symbolic computations, https://www.mathworks.com/help/symbolic/performing-symbolic-computations.ht...

9 giorni ago | 0

Submitted

N-dimensional sparse arrays

Creates an N-dimensional sparse array object, for arbitrary N.

9 giorni ago | 48 downloads |

Answered

How can I use 'Least Squares Solver and Jacobian' instead of 'fminunc'?

Assuming D_d is the Jacobian of myfun, it would be, while (sum(abs(beta_u-beta_d))>0.1 && counter< 500) initial_gues...

How can I use 'Least Squares Solver and Jacobian' instead of 'fminunc'?

Assuming D_d is the Jacobian of myfun, it would be, while (sum(abs(beta_u-beta_d))>0.1 && counter< 500) initial_gues...

10 giorni ago | 0

Answered

How to view centers on a 3D image

One suggestion is to use this FEX file to display the 3D volume with high transparency https://www.mathworks.com/matlabcentral/...

How to view centers on a 3D image

One suggestion is to use this FEX file to display the 3D volume with high transparency https://www.mathworks.com/matlabcentral/...

11 giorni ago | 0

Answered

Comparing the performance of colon, loop, and cell indexing

I checked that it is indeed the case with the Run & Time feature. I don't know what that is, but the better test in any case i...

Comparing the performance of colon, loop, and cell indexing

I checked that it is indeed the case with the Run & Time feature. I don't know what that is, but the better test in any case i...

13 giorni ago | 2

Answered

Using 'fminunc', I receive Optimization completed because the size of the gradient is less than the value of the optimality tolerance.

If the problem doesn't have a solution satisfying the tolerance condition in your while loop (sum(abs(beta_u-beta_d))<0.1) the...

Using 'fminunc', I receive Optimization completed because the size of the gradient is less than the value of the optimality tolerance.

If the problem doesn't have a solution satisfying the tolerance condition in your while loop (sum(abs(beta_u-beta_d))<0.1) the...

13 giorni ago | 0

| accepted

Answered

Join table with different lengths

innerjoin(Grouped_Weight_position{i},Country)

Join table with different lengths

innerjoin(Grouped_Weight_position{i},Country)

13 giorni ago | 1

Answered

Replace array elements with another small array using indexing

b=strrep( strrep(a,[1 4 1],3) ,[3 4 1],2)

Replace array elements with another small array using indexing

b=strrep( strrep(a,[1 4 1],3) ,[3 4 1],2)

15 giorni ago | 0

Answered

Split values in an cell array by using a threshold

One way, A_lower = cellfun(@(x) x(x<threshold), A, 'uni',0); A_upper = cellfun(@(x) x(x>threshold), A, 'uni',0);

Split values in an cell array by using a threshold

One way, A_lower = cellfun(@(x) x(x<threshold), A, 'uni',0); A_upper = cellfun(@(x) x(x>threshold), A, 'uni',0);

15 giorni ago | 0

| accepted

Answered

Too many output argument error while using nested functions?

The code you've posted does not make it clear what problem you are encountering. There doesn't appear to be anything wrong in th...

Too many output argument error while using nested functions?

The code you've posted does not make it clear what problem you are encountering. There doesn't appear to be anything wrong in th...

15 giorni ago | 1

| accepted

Answered

How to multiply a scalar with matrix within loop and for each iteration store the values in new matrix?

There is no need for a loop: C=A.*reshape(b.^(0:n-1),1,1,[]);

How to multiply a scalar with matrix within loop and for each iteration store the values in new matrix?

There is no need for a loop: C=A.*reshape(b.^(0:n-1),1,1,[]);

15 giorni ago | 1

| accepted

Answered

Function lsqnonlin() has no optimization effect

And I have another question. My code has no optimization effect In this case, your initial guess already is optimal. You can se...

Function lsqnonlin() has no optimization effect

And I have another question. My code has no optimization effect In this case, your initial guess already is optimal. You can se...

16 giorni ago | 0

Answered

Linear Extrapolation with interp2

The only remedy I can think of is to pre-pad the edges of the data V with linearly extrapolated values at distant X, Y. That way...

Linear Extrapolation with interp2

The only remedy I can think of is to pre-pad the edges of the data V with linearly extrapolated values at distant X, Y. That way...

17 giorni ago | 0

Answered

overlaps() with only two polyshap objects

Use the two-argument form, Obstacles=[obstacle3 obstacle2]; criterion = sum( overlaps(car,Obstacles) ) == 1 ; %true if one a...

overlaps() with only two polyshap objects

Use the two-argument form, Obstacles=[obstacle3 obstacle2]; criterion = sum( overlaps(car,Obstacles) ) == 1 ; %true if one a...

18 giorni ago | 0

| accepted

Answered

Constraints on meshgrid. Remove points outside function

Just apply logical indexing on the appropriate region and set it to NaN, bad=(y<s11(s2)) | (y>s12(s2)); z(bad)=nan;

Constraints on meshgrid. Remove points outside function

Just apply logical indexing on the appropriate region and set it to NaN, bad=(y<s11(s2)) | (y>s12(s2)); z(bad)=nan;

18 giorni ago | 0

| accepted

Answered

How to run a curve approximation on a script using a function defined in a file and display the goodness of fit in a command window

You can't use the curve fit tool for a curve defined in an mfile. You can use lsqcurvefit, if you have the optimization toolbox,...

How to run a curve approximation on a script using a function defined in a file and display the goodness of fit in a command window

You can't use the curve fit tool for a curve defined in an mfile. You can use lsqcurvefit, if you have the optimization toolbox,...

18 giorni ago | 0

| accepted

Answered

Parallel Processing with Multipul GPUs - fftn

You can use gpuDevice() to select different GPUs for different calculations. gpuArray commands run asynchronously without blocki...

Parallel Processing with Multipul GPUs - fftn

You can use gpuDevice() to select different GPUs for different calculations. gpuArray commands run asynchronously without blocki...

19 giorni ago | 0

Answered

optimization based upon another optimization

You can write anything you want inside the code for your objective function, including other optimization processes. However, fm...

optimization based upon another optimization

You can write anything you want inside the code for your objective function, including other optimization processes. However, fm...

20 giorni ago | 0

Question

Finding handles to figure text

I am attempting to use findobj to retrieve text objects in a plot. For some reason, this fails (R2018a,b). In the following exam...

20 giorni ago | 1 answer | 0

Answered

fmincon nonlinear equality constraint

wopt = fmincon(NegPFMu, w0, [], [], Aeq, beq, lb,[], @(w) mycon(w, Cov, TargetVariance)); function [c, ceq] = mycon(w, Cov, T...

fmincon nonlinear equality constraint

wopt = fmincon(NegPFMu, w0, [], [], Aeq, beq, lb,[], @(w) mycon(w, Cov, TargetVariance)); function [c, ceq] = mycon(w, Cov, T...

22 giorni ago | 1

| accepted