John D'Errico
Retired
Feeds
已回答
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...
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...
11 days 前 | 0
已提交
HPF - a big decimal class
High precision floating point arithmetic, a new class written in MATLAB
16 days 前 | 11 次下载 |
已回答
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...
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...
19 days 前 | 0
已回答
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...
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...
21 days 前 | 0
| 已接受
已回答
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 ...
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 ...
23 days 前 | 1
已回答
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...
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...
1 month 前 | 0
已回答
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,...
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,...
1 month 前 | 0
已回答
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...
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 months 前 | 1
已回答
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
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 months 前 | 0
| 已接受
已回答
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...
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 months 前 | 0
已回答
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...
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...
2 months 前 | 1
已回答
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 ...
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 ...
2 months 前 | 1
已回答
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...
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...
2 months 前 | 1
已回答
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...
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...
2 months 前 | 0
| 已接受
已回答
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...
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...
2 months 前 | 1
已回答
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...
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 months 前 | 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 months 前 | 0
已回答
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...
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 months 前 | 0
已回答
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 ...
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 months 前 | 0
| 已接受
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 months 前 | 0
已回答
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...
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...
3 months 前 | 0
已回答
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...
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...
3 months 前 | 0
已回答
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...
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...
3 months 前 | 0
已回答
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...
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...
3 months 前 | 0
已回答
[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...
[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...
3 months 前 | 0
已回答
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...
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...
3 months 前 | 0
| 已接受
已回答
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, ...
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, ...
3 months 前 | 0
| 已接受
已回答
Precision Loss in Arithmetic Encoding of Binary Vectors for Reversible Data Hiding in 3D Meshes
You are telling us that you effectively have a binary number with 7000 binary bits. You convert it to a decimal number, and then...
Precision Loss in Arithmetic Encoding of Binary Vectors for Reversible Data Hiding in 3D Meshes
You are telling us that you effectively have a binary number with 7000 binary bits. You convert it to a decimal number, and then...
4 months 前 | 0
| 已接受
已回答
SVD to a matrix subset (rows)
No, I don't think you can easily find the SVD of a subset of the rows of a matrix, based on the SVD of the full matrix. At least...
SVD to a matrix subset (rows)
No, I don't think you can easily find the SVD of a subset of the rows of a matrix, based on the SVD of the full matrix. At least...
4 months 前 | 2
已回答
I can not say wether Eigs is giving expected results or not
It is literally trivial to get large differences there. We need not even use eigs. Eig will suffice. A0 = randn(6); A0 = A0 + A...
I can not say wether Eigs is giving expected results or not
It is literally trivial to get large differences there. We need not even use eigs. Eig will suffice. A0 = randn(6); A0 = A0 + A...
4 months 前 | 2
| 已接受
