Mainly retired from Eastman Kodak. (Of course, Kodak itself is now semi-retired. I don't think I had any influence in that.) I still write MATLAB code as I find something interesting, and I do attempt to write new tools to put on the File Exchange when I think I can make a contribution.

However, I DON'T answer direct e-mail questions, and I do NOT do homework. In general, your homework is YOUR problem, not mine. Please do NOT e-mail me with your homework problems or student projects. If I was willing to answer your questions, I would very rapidly become overwhelmed, because one question is never just one simple question.

When I'm not doing something with MATLAB, you might find me playing bridge, either in the club or online on BBO.

Professional Interests: MATLAB, numerical analysis, mathematical modeling

Avocational interests: Bridge, woodworking, woodturning

Answered

What computer should I buy?

READ THE SYSTEM REQUIREMENTS. https://www.mathworks.com/support/requirements/matlab-system-requirements.html They suggest that...

What computer should I buy?

READ THE SYSTEM REQUIREMENTS. https://www.mathworks.com/support/requirements/matlab-system-requirements.html They suggest that...

environ 12 heures ago | 0

Answered

Promoting MATLAB at the higher edu institution I work for

This is not a question you could ask on Answers. Note that we are volunteers, not paid representatives of The MathWorks. As we...

Promoting MATLAB at the higher edu institution I work for

This is not a question you could ask on Answers. Note that we are volunteers, not paid representatives of The MathWorks. As we...

1 jour ago | 0

Answered

Error: index must be a positive integer or logical.

You wrote this: Bs(0)=-(imag(yo)); MATLAB is not whatever other language you came from. MATLAB has an index origin of 1, NOT 0...

Error: index must be a positive integer or logical.

You wrote this: Bs(0)=-(imag(yo)); MATLAB is not whatever other language you came from. MATLAB has an index origin of 1, NOT 0...

1 jour ago | 2

Answered

VAN DER PAUW equation

First, see that no symbolic solution will exist. If we have the general problem: exp(-A*x) + exp(-B*x) == 1 then by the tra...

VAN DER PAUW equation

First, see that no symbolic solution will exist. If we have the general problem: exp(-A*x) + exp(-B*x) == 1 then by the tra...

1 jour ago | 1

Answered

How to increment a variable

To increment a variable X, simply use X = X+1; MATLAB does not support the increment operator ++.

How to increment a variable

To increment a variable X, simply use X = X+1; MATLAB does not support the increment operator ++.

1 jour ago | 6

| accepted

Answered

Function roots. Fixed-point iteration

First, what are the roots? Are you trying to solve the problem q(x) == 0? Or are you trying to solve the problem q(x)==x? A fix...

Function roots. Fixed-point iteration

First, what are the roots? Are you trying to solve the problem q(x) == 0? Or are you trying to solve the problem q(x)==x? A fix...

3 jours ago | 0

Answered

solving nonlinear equation by fsolve

Using max inside an objective that will then be applied to fsolve is a bad idea. It creates a function that is at best non-diffe...

solving nonlinear equation by fsolve

Using max inside an objective that will then be applied to fsolve is a bad idea. It creates a function that is at best non-diffe...

5 jours ago | 0

Answered

Why my result is 0×1 empty double column vector

Um, LOOK AT WHAT YOU DID? eqn eqn = [ 0 == 5780664229092589/18446744073709551616, 0 == 5780664229092589/18446744073709551616,...

Why my result is 0×1 empty double column vector

Um, LOOK AT WHAT YOU DID? eqn eqn = [ 0 == 5780664229092589/18446744073709551616, 0 == 5780664229092589/18446744073709551616,...

6 jours ago | 1

Answered

Getting a smooth curve instead of two linear functions

You have two lines that create what is NOT a function, in the sense that it is single valued. So, for any x, you get a y out. He...

Getting a smooth curve instead of two linear functions

You have two lines that create what is NOT a function, in the sense that it is single valued. So, for any x, you get a y out. He...

6 jours ago | 0

Answered

Y=sqrt((A^2*X^2+B^2*X^2)/(C+D^2*X^2))

People still seem to be missing that the fit will NOT be unique. The model cannot be estimated uniquely as it has been posed. Fi...

Y=sqrt((A^2*X^2+B^2*X^2)/(C+D^2*X^2))

People still seem to be missing that the fit will NOT be unique. The model cannot be estimated uniquely as it has been posed. Fi...

7 jours ago | 2

Answered

How to solve extra long equations with multiple unknowns?

You have two fairly complicated equations, in two unknowns. Why do you expect an analytical solution to exist at all? I'd have b...

How to solve extra long equations with multiple unknowns?

You have two fairly complicated equations, in two unknowns. Why do you expect an analytical solution to exist at all? I'd have b...

8 jours ago | 0

| accepted

Answered

How to explain a bad performance rating using the bench command?

Lots of reasons are possible. The ones that come to mind immediately are: Were you running something else at the same time? Bro...

How to explain a bad performance rating using the bench command?

Lots of reasons are possible. The ones that come to mind immediately are: Were you running something else at the same time? Bro...

8 jours ago | 0

Answered

How do I randomly generate numbers with a certain amount of probability?

As is often the case, I would suggest you are overthinking this. You have a sequence of 24 pairs of images to be shown. There ...

How do I randomly generate numbers with a certain amount of probability?

As is often the case, I would suggest you are overthinking this. You have a sequence of 24 pairs of images to be shown. There ...

11 jours ago | 0

Answered

Randomly dividing an integer (non-uniform distribution)

The problem with the alternative answers given, is they tend to have a flaw, in that they do not sample the space of interest we...

Randomly dividing an integer (non-uniform distribution)

The problem with the alternative answers given, is they tend to have a flaw, in that they do not sample the space of interest we...

11 jours ago | 2

Answered

How to plot a variable in MATLAB which can not be separated explicitly ?

Is ln meant to denote the NATURAL logarithm? If so, then you use log in MATLAB. At first, I thought you mean to write lin, whic...

How to plot a variable in MATLAB which can not be separated explicitly ?

Is ln meant to denote the NATURAL logarithm? If so, then you use log in MATLAB. At first, I thought you mean to write lin, whic...

12 jours ago | 0

| accepted

Answered

could anyone help me how to reshape the matrix.

You are not asking to do a reshape, which does not change the total number of elements. A = A(1,:);

could anyone help me how to reshape the matrix.

You are not asking to do a reshape, which does not change the total number of elements. A = A(1,:);

13 jours ago | 0

| accepted

Answered

generating a sequence of numbers

Not if a1, a2, a3, a4, etc., are separate variables. If that is what you have done, then it is time to learn to program in ways ...

generating a sequence of numbers

Not if a1, a2, a3, a4, etc., are separate variables. If that is what you have done, then it is time to learn to program in ways ...

13 jours ago | 0

| accepted

Answered

extrapolate the plot to the point out of the interval

You can't. Well, you can, but interp1 will give you meaningless garbage, as it should. Extrapolation is a dangerous thing. And ...

extrapolate the plot to the point out of the interval

You can't. Well, you can, but interp1 will give you meaningless garbage, as it should. Extrapolation is a dangerous thing. And ...

14 jours ago | 1

Answered

why it can't be used as a number?

It can be used as a number, IF you understand what you are doing. MATLAB works in DOUBLE PRECISION. A double precision number w...

why it can't be used as a number?

It can be used as a number, IF you understand what you are doing. MATLAB works in DOUBLE PRECISION. A double precision number w...

14 jours ago | 3

| accepted

Answered

An example of using crammers rule or geuss elimination?

Don't use either of them! There are many examples of things that you might learn to use when doing homework, and in class as a s...

An example of using crammers rule or geuss elimination?

Don't use either of them! There are many examples of things that you might learn to use when doing homework, and in class as a s...

14 jours ago | 0

Answered

Cannot use fzero function

My guess is you did not actually save that function as an m-file on your search path. This is why MATLAB could not find the func...

Cannot use fzero function

My guess is you did not actually save that function as an m-file on your search path. This is why MATLAB could not find the func...

15 jours ago | 1

Answered

How to define nuclear norm in matlab?

What is difficult to program? A quick search online suggests it is the L-1 norm of either the vector of singular values, or of t...

How to define nuclear norm in matlab?

What is difficult to program? A quick search online suggests it is the L-1 norm of either the vector of singular values, or of t...

15 jours ago | 0

| accepted

Answered

Why won't this program run?

Because you don't understand how to use the function zeros? Go back to go, do not collect $200, and read the getting started tut...

Why won't this program run?

Because you don't understand how to use the function zeros? Go back to go, do not collect $200, and read the getting started tut...

15 jours ago | 1

Answered

It doesn't give a result. mablab couldn't take the integral of M = cos(2*pi*a*ti);

"It doesn't give a result. mablab couldn't take the integral of M = cos(2*pi*a*ti);" Actually, the failure arises because you d...

It doesn't give a result. mablab couldn't take the integral of M = cos(2*pi*a*ti);

"It doesn't give a result. mablab couldn't take the integral of M = cos(2*pi*a*ti);" Actually, the failure arises because you d...

15 jours ago | 2

Answered

unbounded problem in linprog but not in fmincon

This is your problem? A=[ 1 1 1 0 0 0 0 0 0; -2.5 0 0 1 -1 0 0 0 0;0 -3 0 0 0 1 -1 0 0;0 0 -20 0 0 0 0 1 1;0 0 0 0 0 0 0 1 0]; ...

unbounded problem in linprog but not in fmincon

This is your problem? A=[ 1 1 1 0 0 0 0 0 0; -2.5 0 0 1 -1 0 0 0 0;0 -3 0 0 0 1 -1 0 0;0 0 -20 0 0 0 0 1 1;0 0 0 0 0 0 0 1 0]; ...

16 jours ago | 2

| accepted

Answered

Solve tridiagonal matrix system by thomas algorithm

Is it obligatory to create a matrix with those specific elements? Of course not. As long as you know what elements have which va...

Solve tridiagonal matrix system by thomas algorithm

Is it obligatory to create a matrix with those specific elements? Of course not. As long as you know what elements have which va...

16 jours ago | 0

| accepted

Answered

Heun's method

Is there a general code? No, unless you write it, or find it on the file exchange. Why should there be?

Heun's method

Is there a general code? No, unless you write it, or find it on the file exchange. Why should there be?

16 jours ago | 0

Answered

How to plot a nonlinear equation using FSOLVE in MATLAB

You have an implicit function. So a relationship involving two variables, where there is no way to resolve one as a function of ...

How to plot a nonlinear equation using FSOLVE in MATLAB

You have an implicit function. So a relationship involving two variables, where there is no way to resolve one as a function of ...

17 jours ago | 0

| accepted

Answered

Obtaining a fourth order of accuracy approximation formula for y''(0) and findind rhe unknown coefficients

Save this function as an m-file, NOT in the MATLAB directories, but on your search path. function ypp = accuracyapprox syms ...

Obtaining a fourth order of accuracy approximation formula for y''(0) and findind rhe unknown coefficients

Save this function as an m-file, NOT in the MATLAB directories, but on your search path. function ypp = accuracyapprox syms ...

18 jours ago | 0