John D'Errico
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Are iterative methods always better than direct methods for solving large linear systems?
The use case which some may miss here, is the very large array, where a dense solver fails due to memory, but even the sparse on...
circa 14 ore fa | 1
solving a system of linear equations where A is a 40*40 sparse matrix
I'd suggest that sparse is almost meaningless when the matrix is only 40x40. At that point, the dense solvers are still extremel...
2 giorni fa | 2
Putting spaces between elements of a string/
A = ['011001110000';'101111000000';'110100011000';'011010001100';'010101000110';'110010100010';... '100001010011';'10100010...
8 giorni fa | 2
| accettato
How to download the certificate
I'm sorry, but no, we cannot resolve your problem. Answers is not customer support. Answers is a volunteer forum, generally comp...
28 giorni fa | 0
Inviato
HPF - a big decimal class
High precision floating point arithmetic, a new class written in MATLAB
circa un mese fa | 18 download |
Defining inequality constraint A*x <= b for genetic algorithm
As I said in my comment, you cannot set up a linear system of inequalities to constrain that curved path from self intersections...
circa un mese fa | 0
i want to add cplex and yalmip on my mac how ?
YALMIP is an external toolbox, written in MATLAB, so it could in theory be used by any MATLAB installation. However, it is proba...
circa un mese fa | 0
| accettato
flag a question as answered.
While DGM gave a very complete answer, worthy of acceptance in my eyes, I think, from a look at one of the other questions from ...
circa un mese fa | 1
Finite elements model using STABIL
I cannot test your code, as I lack the tools you are using. Regardless, IF you tell us the solve yields NaNs, then there are onl...
circa 2 mesi fa | 0
Using logic to select specific values in a matrix
Well, you are doomed to failure, as long as you don't use the right variable names as you created them! A = [1, 0.1234 1,...
circa 2 mesi fa | 0
In how many functions using the global variable, can a global variable be declared?
There is no limit on how many functions can use a global variable. At the same time, I will plead, for your own sanity, to recon...
2 mesi fa | 1
How do I plot a graph with the grid for trig functions with 0 ≤ x ≤ 2π
@Sean syms x f = cos(x) dfdx = diff(f) help fplot
2 mesi fa | 0
| accettato
Should I need keep in my PC previous versions of Matlab?
Some of us keep older releases, just to answer a question about an older release, testing out code in the old release. I do ten...
2 mesi fa | 0
Unable to fetch more decimal points for values stored in sldd
You need to learn about the format command. All of the digits are still there, they were just not reported. I'll add a few digit...
3 mesi fa | 1
The symbol "1" is not a scalar in integral3
If ALL you want to do is compute a volume, especially of such a simple domain, there are better ways to do so. If the domain is ...
3 mesi fa | 1
How does the svd function determine or fix the phase of singular vectors?
First, signs are to some extent arbitrary. That is, for EIG, you can multiply an eigenvector by -1, and it is still an eigenvect...
3 mesi fa | 1
Obtaining the differential equations from graphical representation of the problem
Can you show that a set of equations is a valid representation of some data, merely by comparing them to a curve you find in som...
3 mesi fa | 0
| accettato
Will the old-style class definitions be supported in future version of Matlab?
One thing you cannot realistically ask on Answers (if you expect a fully valid answer) is what decisions about MATLAB will be ma...
3 mesi fa | 1
Modelling a system of differential equations with recurrences in matlab
This is known as a delay differential equation. You will find any solvers for them starting with the letters dde. help dde23 Y...
3 mesi fa | 0
Discussion
OH NO! isprime is missing? (Just kidding)
What if you had no isprime utility to rely on in MATLAB? How would you identify a number as prime? An easy answer might be some...
3 mesi fa | 0
Iterating the eigenvalue function (eig) produces patterns --- is this a well known result?
I'd have a hard time believing this is well known. @Christine Tobler would be the one to know though, and she agrees. It just f...
3 mesi fa | 0
Question on the format of 2D curve fit equations in plot
Scientific notation. 6.588e + 06x^2 == 6.588*10^6 * x^2 Note that it is easier and faster to write, and even a bit easier to ...
3 mesi fa | 0
| accettato
Discussion
Approximating a floating point number with a finite representation in decimal form
I saw an interesting problem on a reddit math forum today. The question was to find a number (x) as close as possible to r=3.6, ...
3 mesi fa | 0
How do I find the average of a vector of units by using a for loop?
When you create a variable name, NEVER, NEVER, NEVER use a name that is an existing and useful function name. (Well, it might be...
4 mesi fa | 0
how to find orthonormal vector with condition?
Confusing question. Which probably means I'm misunderstanding your goal here, or that I am myself confused, which is not uncommo...
4 mesi fa | 0
Closed contour with least square differences to dataset
This can be quite difficult if you have some completely arbitrary form. But you tell us this is a simple closed form. And as lon...
4 mesi fa | 0
MATLAB R2018a needed
We cannot give you a copy of MATLAB. Answers is not customer support anyway. And even they don't just give out copies for anyone...
4 mesi fa | 0
[coeffA,scoreA,latentA] = pca(X);
The editor likes to complain. Just the kind of program it is. Think about this as a suggestion, a hint, in case maybe your code...
4 mesi fa | 0
How to define 1-bit variable in data dictionary?
MATLAB does not have a true 1-bit data class. Even a logical, which is clearly a 1 bit thing, thus either true or false, is sto...
4 mesi fa | 0
| accettato
Polyfit isn't adjusting to decreasing sinoidal data
Do you appreciate just how NON-polynomial-like this data is? Your data appears to be a variation of decaying sinusoid. While, ...
4 mesi fa | 0
| accettato
