Community Profile # Matt J

Last seen: Today Active since 2009

Professional Interests: medical image processing, optimization algorithms

#### Statistics

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

View by

I dont understand why my table is displaying 1x1 sym and not a numerical value
You seem to be under the impression that vpa() converts a sym to a number. What you really want to do is use matlabFunction() to...

alrededor de 3 horas ago | 0

How can I create a set of N diagnal matrices range from diag(1, 1, ... , 1) to diag(-1, -1, ... , -1) for testing purposes?
Do you really need all Z{i} at the same time? [C{1:4}]=ndgrid([-1,1]); C=reshape( cat(5,C{:}) ,[],4); Z=zeros(N^2,2^N); %...

alrededor de 15 horas ago | 1

Non-linear constraints with several input variables in fmincon
Your nonlinear constraints are not differentiable. That doesn't always spell disaster, but it breaks the assumptions of fmincon....

alrededor de 15 horas ago | 0

fsolve, fmincon producing different results
Do they both achieve the same objective value? If so, you simply have multiple solutions.

alrededor de 16 horas ago | 0

How to extract columns from multiple 3D arrays?
Seems like you could just put them in a matrix: F=[f1(:), f2(:),f3(:),...,f7(:)]

alrededor de 16 horas ago | 0

| accepted

How to Solve matrix equations in Matlab
With an over-determined system (3 equations and only 2 unknowns), you can't expect an exact solution. However, the solution that...

alrededor de 19 horas ago | 1

| accepted

Efficiently assigning class property in a quadruple loop?
You've not told us the dependence of myLogicalVector and someFixedValue* on the loop variables, which is probably super-importa...

3 días ago | 0

Double Summation without using fft2 function
You can find examples of for-loop construction here, https://www.mathworks.com/help/matlab/ref/for.html#buhafgy-3

3 días ago | 0

Sequence 1, 2, 4, 12
One possibility: p=[0.833333333333333 -4.499999999999996 8.666666666666661 -3.999999999999996]; polyval(p,1:4) polyval(...

3 días ago | 0

How to get optimal linear scaling factor for a set of vectors
I want to determine a linear scale factor for each y_raw? vector, such that the mean squared error (MSE) between the average of ...

4 días ago | 0

| accepted

Linear Equations infinite solutions parametric form
x0=pinv(A)*b; B=null(A); sol=@(c)x0+B*c;

4 días ago | 1

| accepted

How can I speed up (or avoid) a comparison in for loop?
You might try bwlareaopenn from this submission https://www.mathworks.com/matlabcentral/fileexchange/90762-further-tools-for-an...

4 días ago | 1

Solver based optimization passing extra parameters

4 días ago | 0

How to get the file names that start with the same letter in the folder?
For example, s=dir('T*_imag.bin'); fileNames={s([s.isdir]==0).name}

4 días ago | 0

Matrix form for creation and annihilation operator with spins.
Not sure this will help, but if you can write a function that implements the operator, then his File Exchange offering, https:/...

4 días ago | 0

What should go in a next-generation MATLAB X?
My wish list: (1) Colon operator produces column vectors, not row vectors: x=1:4 (2) Optimization Toolbox solvers should ha...

4 días ago | 2

combine different size vectors into one matrix
I will assume you have the vectors in a cell array C={[2 3 4 5]; [4 7 7]; [8 8 7 4 2 5]} Then, you can simply do, z=...

4 días ago | 0

using fsolve function to solve for 2 unknowns
x0 = [80,110]; [sol, Fsol] = fsolve(@problem_one,x0), function F = problem_one(theta) theta3 = theta(1); theta4 ...

6 días ago | 1

| accepted

fminunc initial point is local minimum, but fminsearch returns reasonable estaimtes
It could happen if your objective function is piece-wise flat (and hence non-differentiable). fminsearch is a derivative-free so...

6 días ago | 0

| accepted

How can I obtain the Fourier Transformation as a product of matrices?
N = (0:255).'; X = (2*cos(((15.8*pi)/128)*N)) + (3*sin(((27.3*pi)/128)*N)); F=fft( eye(numel(X)), [],1); fX = fft(X); %...

6 días ago | 0

| accepted

How to plot binary matrix as dots?
imshow(yourMatrix)

6 días ago | 0

Solving non linear equation "Circle" equations
Because you cannot be certain of an exact 3-way (or n-way) intersection, you need to use a numerical least squares solver like f...

6 días ago | 1

| accepted

What is the real value of "single(my_variable)"?
So the C code keeps good precission. But, does Matlab? Yes, if by "good precision" you mean up to 7 digits. You can see that ev...

6 días ago | 0

How to define a constat in function handle?
You mean like this? [a,b,c]=deal(3,4,5); f = @(x,y)a*x.^2+b*y+c Or like this? syms x y a b c f(x,y) f(x,y)=a*x.^2+b*y+...

6 días ago | 0

| accepted

Steepest descent with exact line search method
n=input("Enter the roll number:"); fobj=@(x) (x(1)-n)^2 + (x(2)-2*n)^2; gradobj=@(x)2*[(x(1)-n), (x(2)-2*n)]; x0=[1 1]; ...

6 días ago | 0

how to develope loop to save the 'n' elements from the vectors
It is not a good idea to store A(i) in separate variables. You should probably just write your equation in terms of vector opera...

6 días ago | 2

Taylor series approximation problem
As an example, syms x T=taylor(exp(-x),x,7,'Order',4) fn=matlabFunction(T) fn(3) You can of course find more examples...

6 días ago | 0