Answered
Unable to resolve the warning on ill conditioned Jacobian
A not uncommon misunderstanding about modeling. First, look carefully at your data. M = importdata('datai2j3.txt'); x = M(:,1...

1 year ago | 0

Answered
volume of set of points in 3d space with gap
Is there any way you can make the convex hull adequately represent a region that is not in fact convex? Of course not! You have...

1 year ago | 0

Answered
Problems by calculating zero points of a cubic function
Or, you can use analytical tools. syms x a f = -2*x^3 + x^2 + 0.5*x -8; % Remember to use * to multiply fa = f + a; Before y...

1 year ago | 0

Answered
How to choose a single element randomly from a vector
I've upvoted the answer by @R. Please accept it. My answer here is only to express some ideas that are really best put in a comm...

1 year ago | 0

Discussion

Using MATLAB to find a generative equation for a sequence
This stems purely from some play on my part. Suppose I asked you to work with the sequence formed as 2*n*F_n + 1, where F_n is t...

1 year ago | 8

Answered
Setting unknown constants in equation for known data
This is the classic regression problem, either linear or nonlinear, and that depends on how the parameters enter into the "model...

1 year ago | 1

Answered
Efficient management of interacting atoms based on their mutual distance
No. It is NOT true that in a set, if atom x is one of the k closest atoms to atom y, that the converse is also true, i.e., that ...

1 year ago | 0

Answered
Numerical integration of area
The region in color? The integral will be negative, or course, since depth is entirely negative. But you perform such an integr...

1 year ago | 1

| accepted

Answered
Particle Swarm Optimization - What method is used to find local minimum?
Particle swarm optimization, https://en.wikipedia.org/wiki/Particle_swarm_optimization is one of many meta-heuristics used to ...

1 year ago | 0

| accepted

Answered
Any ideas for making this exponential decay function match the actual data better?
(I spent so much time writing this as a comment, I might as well make it an answer.) @Image Analyst asks a valid question. I ha...

1 year ago | 1

Answered
Remove exponentials with positive argument in symbolic MATLAB
Very often symbolic computations are less easy than you want them to be, because the computer does not see one thing as simple v...

2 years ago | 0

Answered
I need to create a polygon or buffer along an irregular shaped coastline in a 2D array of gridded sea temperature data.
Easy enough. Almost trivial, in fact. Of course, making a buffer zone of width exactly one pixel is alays going to be slightly p...

2 years ago | 0

Answered
Derive full formula from fitlm(X,y,"quadratic")
X = rand(258,6); y = rand(258,1); mdl = fitlm(X, y, "quadratic") There are 6 variables, here called x1...x6, corresponding ...

2 years ago | 1

| accepted

Answered
Running a large array
Memory is cheap. Get more memory. I'm sorry, but if you want to work with big data, you will often need sufficient capabilities...

2 years ago | 0

Answered
Why did I get two different results in nonlinear programing problems
You have a nonlinear problem. You need to understand that given any set of starting values, an optimizer will sometimes find a s...

2 years ago | 0

Answered
The equation of the curve at the intersection of the two 3D surface, One is a cylinder.
It is not always trivial to find that curve as some explicit function. Here, yes, you can do so easily enough. syms x y z r = ...

2 years ago | 2

| accepted

Answered
creating loop that stops at correct formula for the given input.
You have a fundamental problem here, that you fail to understand. You CANNOT solve for more than 6 parameters, given only 6 data...

2 years ago | 0

| accepted

Answered
Help solving linear ordinary differential equation that involves matrix
I would postulate that in fact, it DOES give the correct solution, at least to the problem you posed, but that it is not in the ...

2 years ago | 0

Answered
How to solve this problem combining sequences and reasoning using code?
I would probably think first, and only then write code. I gather the global sequence will always be 1:(4*m+2), so the first 4*m+...

2 years ago | 0

Answered
Find closest value in array
To be honest, the easiest way is to use knnsearch. It works well in one dimension, as you have here, and it should be quite effi...

2 years ago | 2

Answered
Calculations with distributions of variables only
Um, yes. And, no. Firstly, very likely there will be no "named" distribution for even such a simple expression. And depending ...

2 years ago | 0

Answered
How to fastly calculate this matrix operation
First, use better variables. I is a terrible name to use , especially capital I, since it is so easily confused with the number ...

2 years ago | 0

| accepted

Answered
Find the turing pattern for following equation
I won't do your homework, since this is highly likely to be homework with no effort made on your part, just from the way you ask...

2 years ago | 0

| accepted

Answered
In Pskmod Code: Reshaping the output signal using the transpose operator .' , Introduce a sign change.
No. You have it wrong. Completely backwards, in fact. The .' operator does NOT cause a sign flip. That is called a conjugation. ...

2 years ago | 0

Answered
Why am I getting gaps in my data when I attempt to interpolate my curve?
As is always the case, look at what you did. Think about it. If necessary, think again. xy = readtable('Sample Test.txt') plot...

2 years ago | 2

| accepted

Answered
How to call a own function in other mfile?
Did you save it on your search path? (Do you know what your search path is?) Spend some time reading the help for tools like add...

2 years ago | 0

Answered
Show Only certain variables in the workspace
The point of what @Stephen23 and I are trying to tell you is that you are asking the wrong question. You want someone to teach y...

2 years ago | 0

Answered
Solve a system of two variable inequalities with symbolic toolbox
fimplicit does not plot inequalities. Sorry. If you read the help, it never says anything about inequalities. Simplest is to ju...

2 years ago | 0

| accepted

Answered
How to fix "Error using indexing" while calculating differential equations?
The code you show will work perfectly in MATLAB, in literally any recent release of MATLAB. R2023 is entirely recent. However, ...

2 years ago | 0

Answered
Writing a code to determine the gradient change in a profile
Your problem lies in this line: change_p = (abs(data.variable.gradpressure(i,j+1))-abs(data.variable.gradpressure(i,j)))/abs(da...

2 years ago | 0

| accepted