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John D'Errico


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4.745 total contributions since 2006

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Answered
using the mod function to create and even random number generator in matlab
Why do you need the mod function? Just generate random integers, and then MULTIPLY THEM BY 2.

circa 9 ore ago | 0

Answered
Newton's Method in Matlab
First, consider if you are trying to solve the wrong problem. In your question, you state it as e^2*sin(x) - x = 0 However, in...

circa 10 ore ago | 0

| accepted

Answered
getting error while trying to write a code to solve general case diagonal Ax=b matrix
You should probably read the getting started tutorials, since you are using syntax that does not do what you think it does in MA...

1 giorno ago | 1

| accepted

Answered
8 nonlinear equations, 8 unknowns - little luck with fsolve/vpasolve
This same question gets asked on literally a daily basis. The problem is not fsolve. It lies in understanding nonlinear equation...

3 giorni ago | 0

Answered
I have a problem. It can not run. Help me please.
When you say only that something does not run, then tell people what was the error message. Show the COMPLETE error message. Thu...

3 giorni ago | 1

Answered
How to divide a distance into some equal parts?
You have two points. Call they xy1 and xy2, where the xy are row vectors of length 2. For example... xy1 = [-1,3]; xy2 = [2,5]...

3 giorni ago | 0

Answered
Replace the empty output of find() by the closest element
You are trying to use the wrong tool (i.e., find) to solve this. Well, you could use find, I suppose, with some significant effo...

4 giorni ago | 4

| accepted

Answered
Calc of mean and standard deviation
It should look like what photo? The mind reading toolbox has never gotten past beta testing state, and the copy I have is full o...

5 giorni ago | 0

Answered
How do I obtain the derivatives after interp2 with the 'spline' option?
interp2 does not return derivative information at the interpolation points. If you want to generate that at some general interp...

5 giorni ago | 0

Answered
fminsearch for fitting a function to experimental data
Even after you fix the problems in multiplication, let me look at your model and your data. syms c2 k12 k2e t fun = 120*c2*k12...

6 giorni ago | 0

Answered
Symbolic solution trigonometric equation
Why not try it? syms a b c x >> xsol = solve(a*sin(b*x) + sin(c*x) == 0,x) Warning: Unable to find explicit solution. For opt...

7 giorni ago | 0

Answered
How do i calculate these 3 unknows in these Equations
Easy enough. syms a b c x y z EQ(1) = a^2 + b^2 + a*b == x^2; EQ(2) = b^2 + c^2 + b*c == y^2; EQ(3) = a^2 + c^2 + a*c == z^2...

7 giorni ago | 1

| accepted

Answered
How to create a best fit line for data with an aymptote?
It partly depends on your goal. Do you just want to best estimate the constant asymptote? Or, are you looking for some function ...

8 giorni ago | 0

Answered
selection of n disticnt vector
Easy enough. A = 1:10; index = randperm(10,6); a = A(index(1:3)); b = A(index(4:6)); Since randperm generates samples witho...

9 giorni ago | 0

Answered
how do I write variance in percentage?
A percentage of what? Percentage always implies you are comparing one number to another. That is, suppose you have some variable...

9 giorni ago | 0

Answered
Can I update a toolbox without updating Matlab?
Short answer: No. Long answer: Nnnnnooooooooo. Why not? You can't do it, because then the versions would not be consistent. Ju...

9 giorni ago | 0

| accepted

Answered
Matlab implementation of AlphaZero
Now that I have some free time... I'm pretty sure the answer is no. Alphazero is a tool that was developed that could learn g...

10 giorni ago | 0

Answered
scatter3 error i not understand
Hmm. It took me a minute to see what the answer was from the error that was generated. scatter3(X,Y,Z,P) Error using scatter3 ...

10 giorni ago | 1

Answered
How can I write a function for this
Use plotregion, found on the file echange. https://www.mathworks.com/matlabcentral/fileexchange/9261-plot-2d-3d-region Note th...

10 giorni ago | 0

Answered
Getting the linear portion of a non-linear curve
As is often the case on a question like this, you have been too vague for us to comprehensively understand what you do "have". (...

10 giorni ago | 2

Answered
rotating this curve 20degrees
I would normally ask why not try it yourself, but I realize there are some issues that can easily catch you here. H = plot(t,sd...

11 giorni ago | 2

Answered
Why 4.8/1.6 is not equal to 3?
While there has been a lot of good discussion in the other answer, let me add a few points. When you type 4.8 in MATLAB, does ...

13 giorni ago | 1

Answered
How can I solve linear equation system in parallel?
You already are doing that! That is, decomposition uses all of the cores you have available for large problems. Watching my ac...

14 giorni ago | 1

| accepted

Answered
How can I get confidence intervals when the Jacobian matrix has an almost zero vector?
This is probably not a failure of the assumption of Gaussian arrors, though that may indeed be the case too. I cannot know. Wha...

14 giorni ago | 0

Answered
Can I run MAtLab on mac
Yes. Apparently so. https://www.mathworks.com/support/requirements/matlab-system-requirements.html

14 giorni ago | 0

Answered
Fit a conic section without mirror image hyperbola
This goes back to basic algebra. When does a conic section describe an ellipse versus a hyperbola? https://en.wikipedia.org/wik...

14 giorni ago | 0

Answered
Distance between points of a 3D centreline
Why not try diff? For example, what does diff(CL,[],1) do? TRY IT! What is distance? Does that give you something you might b...

16 giorni ago | 0

Answered
Signal into tolerance range - Comparison algorithm
It is often the case when my answer wants to be both no and yes. That is, no, there is no direct tool that does what you seem to...

16 giorni ago | 0

Answered
How to graphically represent the global minimum of an optimization problem with more than two variables?
Do you have a multi-dimensional holographic monitor? Yes, I know, this will not be invented for many years if ever, but that is ...

17 giorni ago | 0

Answered
Fast method to find average pairwise distance of a very large matrix?
You cannot compute the 100 billion pairwise distances, because the matrix won't fit in memeory. (Ok, symmetry reduces it to be o...

17 giorni ago | 0

| accepted

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