Community Profile # Matt J

Last seen: Today Active since 2009

Professional Interests: medical image processing, optimization algorithms

#### Statistics

All
• • • • • • • • • • • • #### Content Feed

View by

How to avoid using det, when looking for the complex root w with det(M(w)) = 0
Because your matrix appears to be symmetric, I suggest minimizing instead norm(M(w)) which is the maximum absolute eigenvalue of...

1 hour ago | 0

Optimisation functions: Skipping iterations if objective function returns an error or cannot run completely
Basically, the option available to you is to return inf from your objective when an error condition is reached. Some optimizatio...

22 hours ago | 0

fill a vector (efficiently) with values specified by matrix and multiple vectors
M=reshape(1:8,2,2,2);N=10; x=(rand(N,1)>0.5)+1;y=(rand(N,1)>0.1)+1;z=(rand(N,1)>0.1)+1; OUT=M( sub2ind(size(M),x,y,z) ...

22 hours ago | 0

Interpolating points in a 3D space with one line
You can use linear3dFit() from this FEX submission https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-t...

2 days ago | 1

how to handle soft weight constraints in neural network
If you wish to train with standard unconstrained stochastic gradient descent algorithms, you will probably have to make a custom...

2 days ago | 0

| accepted

Convert decimal and negative values ​​to integers
Something like this, perhaps? a = 0:pi/100:2*pi; x=cos(a); y = sin(x); fcn=@(z)round(rescale(z,0,intmax('uint16'))); pl...

2 days ago | 0

why do we need to flip kernel before using conv2 in CNN?
The field of neural networks uses the term "convolution" loosely. There are other differences as well. We also know that in trad...

2 days ago | 0

Applying the Nonlinear Least Squares Method to Minimize the Objective Function to Find the Parameters of the Equation
Your code makes strange assumptions about the output syntax of lsqnonlin. [x,resnorm,residual,exitflag,output,lambda,jacobian] ...

2 days ago | 0

| accepted

Trying to solve a matrix with four equations and four unknowns. Should be three non zero terms.
You cannot paste a function definition into the command window. Put it in a file and run it in the Maltab editor. Also, you are ...

3 days ago | 0

| accepted

How I can separate the data points by line?
You could use fitclinear. To illustrate, I will use fabricated data: %synthetic data N=500; Resistivity=rand(N,1); Porosity=...

3 days ago | 0

Create a sliding window
matrix=reshape(vector,5e5,[]) This gives a matrix whose i-th window is matrix(:,i). How best to process that, though, depends o...

4 days ago | 0

A*1 and A+0 could be faster.
My sense of things is that, in the situations where you would care about such special case optimizations, you would know in adva...

4 days ago | 1

| accepted

[RHSval,kprimeind] = max(RHSvec,[],2,'linear'); kdpolind(act,kprimeind)= vector_that_is_51x1

5 days ago | 0

Why do I receive the array indices must be positive intergers or logical values
You haven't provided the input necessary to run your code, but it looks like tempo_fix-60 could be <=0.

5 days ago | 0

Calculate the value of an area around a known co-ordinate
mean(Thermal(y-1:y+1,x-1:x+1),'all')

5 days ago | 0

| accepted

Submitted

spatialgraph2D
Creates a graph object with 2D spatial locations associated with the nodes Interpolation of the values of points on the surface created by convex hull
For example, was the question targeted at sampling new points on the surface...? Assuming that's the correct interpretation, th...

5 days ago | 0

how to range data and find maximum value for each range by using loop
AB=[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16; 10 5 7 8 3 18 20 3 6 66 2 14 39 40 4 20].'; [maxval,i]=max(reshape(AB(:,2),4,[]),...

6 days ago | 0

| accepted

Generate Field Names from Variables While Accessing Elements of a Nonscalar Structure Array
Why not a 2D struct array, R(nDriver,1).LapData(nLap).LapTime R(nDriver,2).LapData(nLap).LapTime R(nDriver,3).LapData(n...

6 days ago | 0

How to find the index of a particular child when using use parallel = True option in genetic algorithm optimizer?
If you have the Parallel Computing Toolbox, set UseParallel=false and UseVectorized=true. Then, inside your objective function a...

6 days ago | 1

How can i solve this cost function?
v = [(1 / (0.47 * 0.94 * 1500)^2) (1 / (0.47 * 0.94 * 1700)^2) (1 / (0.47 * 0.94 * 2000)^2) (1 / (0.47 * 0.94 * 2200)^2)]; delt...

7 days ago | 1

| accepted

Text comparisons no longer work with arrays in 2022a
There's been no change. cell arrays containing character vectors still work: contains({'dog','fish','cat'},'cat') What does no...

8 days ago | 1

How to find the constant of a line function
Evaluate the function at x=0.

8 days ago | 0

| accepted

Min of each column of a sparse matrix?
result = -log( max( spfun(@(x)exp(-x), yourMatrix) ,[],1) );

8 days ago | 0

Create random numbers inside a specific plane in xy plane
I don't understand how you are specifying your parallelograms. However, one way is to use ndgrid and then apply a shear: [X,Y]=...

8 days ago | 0

Generating all unique binary vectors of length N given certain criteria
N=5; A=triu(ones(N)); B=~eye(N); B=B(2:end-1,:); c=nchoosek(2:N-1,2); C=(1:N); C=C<c(:,1)|C>c(:,2); result=...

8 days ago | 0

| accepted

How to join or merge two Image Data Stores?
Perhaps by wrapping them in a TransformedDataStore (R2019a and higher), imdsnew = transform(imds1,imds2, @(x) x)

8 days ago | 0