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

sparse matrix operations to gain efficiency

Are those matrices mostly zero? No. It looks like they are 50% zeros. Sparse will not gain anything, because thre is also overhe...

sparse matrix operations to gain efficiency

Are those matrices mostly zero? No. It looks like they are 50% zeros. Sparse will not gain anything, because thre is also overhe...

약 20시간 ago | 0

| accepted

Answered

How does function std process complex numbers

std uses the formula that is given by David, which is just the standard fornula, with no difference for complex inputs. But just...

How does function std process complex numbers

std uses the formula that is given by David, which is just the standard fornula, with no difference for complex inputs. But just...

1일 ago | 0

Answered

I need help in this question please?

What are you trying to do with the lines: syms B assume(B>1) Which have nothing to do with the problem? It looks like they a...

I need help in this question please?

What are you trying to do with the lines: syms B assume(B>1) Which have nothing to do with the problem? It looks like they a...

1일 ago | 2

Answered

how to apply cubic spline interpolation curve fitting

What I think you do not understand is those curves are noisy, and you do not understand splines. The curves you drew are not noi...

how to apply cubic spline interpolation curve fitting

What I think you do not understand is those curves are noisy, and you do not understand splines. The curves you drew are not noi...

2일 ago | 0

Answered

please explain diag([rand(1,n-2) + 1, 1, 17])

When you have a problem, take it apart from the inside. What is inside-most? Was diag called with multiple inputs at all? (No.) ...

please explain diag([rand(1,n-2) + 1, 1, 17])

When you have a problem, take it apart from the inside. What is inside-most? Was diag called with multiple inputs at all? (No.) ...

3일 ago | 2

| accepted

Answered

How can I calculate the slope of third order polynomial fit

Is there a reason why you would not think to differentiate it? help polyder

How can I calculate the slope of third order polynomial fit

Is there a reason why you would not think to differentiate it? help polyder

4일 ago | 0

Answered

Symbol calculation and numerical values

You are doing things in the wrong order. k,e,m,w are not unknowns. They are knowns. So why have you set them up as symbolic? N...

Symbol calculation and numerical values

You are doing things in the wrong order. k,e,m,w are not unknowns. They are knowns. So why have you set them up as symbolic? N...

4일 ago | 0

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Answered

How to construct a weighed 2D histogram?

Just use accumarray to sum the weights in each bin.

How to construct a weighed 2D histogram?

Just use accumarray to sum the weights in each bin.

4일 ago | 0

Answered

How can I convert red curve in an image into a line ?

What does it mean to convert something into a "curve"? In fact, there is no need to do anything of the sort. You have a picture...

How can I convert red curve in an image into a line ?

What does it mean to convert something into a "curve"? In fact, there is no need to do anything of the sort. You have a picture...

5일 ago | 1

| accepted

Answered

Sine curve fit to data with an unknown dc offset

Of course it is possible. Use the curve fitting toolbox. ft = fittype('a + b*sin((x - c)/d)','indep','x'); mdl = fit(X(:),Y(...

Sine curve fit to data with an unknown dc offset

Of course it is possible. Use the curve fitting toolbox. ft = fittype('a + b*sin((x - c)/d)','indep','x'); mdl = fit(X(:),Y(...

6일 ago | 0

| accepted

Answered

How can I check if a variable exists within another variable?

It fails, because exist does not apply to fields of a strcture. help isfield isfield True if field is in structure array.

How can I check if a variable exists within another variable?

It fails, because exist does not apply to fields of a strcture. help isfield isfield True if field is in structure array.

8일 ago | 0

Answered

random numbers without repetition of two consecutive numbers

These things are far easier than you think. In fact, there are (at least) two simple ways to solve it. Generate multiple sets ...

random numbers without repetition of two consecutive numbers

These things are far easier than you think. In fact, there are (at least) two simple ways to solve it. Generate multiple sets ...

8일 ago | 4

Answered

im not able to run below given code

Now that we know what the problem is, those functions are part of the Phased Array System toolbox. https://www.mathworks.com/he...

im not able to run below given code

Now that we know what the problem is, those functions are part of the Phased Array System toolbox. https://www.mathworks.com/he...

9일 ago | 0

Answered

alpha shape vs convex hull volume value

A problem with your data is it has holes in it. The inside looks to be empty. But worse, it has a void on one corner, where the ...

alpha shape vs convex hull volume value

A problem with your data is it has holes in it. The inside looks to be empty. But worse, it has a void on one corner, where the ...

11일 ago | 2

| accepted

Answered

Rank of Symbolic Matrix returns incorrectly

"Concuded by inspection." I've gotta laugh at that. B = [ 1, -1, -1, ...

Rank of Symbolic Matrix returns incorrectly

"Concuded by inspection." I've gotta laugh at that. B = [ 1, -1, -1, ...

13일 ago | 1

Answered

Interpolating from set of vectors to another with some tolerance?

Confusing as hell. You have one set of values as a pair of vectors, (xfine_i,Tfine_i). As well, you have the same thing at a c...

Interpolating from set of vectors to another with some tolerance?

Confusing as hell. You have one set of values as a pair of vectors, (xfine_i,Tfine_i). As well, you have the same thing at a c...

13일 ago | 0

| accepted

Answered

construc matrix D by OD process?

I suppose I'll make this an answer instead of just a comment, since nobody has answered yet. If all you wanted is to construct ...

construc matrix D by OD process?

I suppose I'll make this an answer instead of just a comment, since nobody has answered yet. If all you wanted is to construct ...

13일 ago | 1

| accepted

Answered

Solving trigonometric equation using "solve" function.

Whats the problem? There is no need to set any properties anyway on such a trivial problem. syms x; x = solve(230.769*cos(x)+1...

Solving trigonometric equation using "solve" function.

Whats the problem? There is no need to set any properties anyway on such a trivial problem. syms x; x = solve(230.769*cos(x)+1...

14일 ago | 0

| accepted

Answered

how to create a symmetric binary variable matrix

You need to learn to index matrices, as you have been posting repeatedly what are virtually the same questions. Fundamentally, w...

how to create a symmetric binary variable matrix

You need to learn to index matrices, as you have been posting repeatedly what are virtually the same questions. Fundamentally, w...

17일 ago | 0

| accepted

Answered

Display numbers as power of N in a symbolic expression?

I don't think you can, at least, not easily. You can do pretty much anything with sufficient effort of course. syms X expr = e...

Display numbers as power of N in a symbolic expression?

I don't think you can, at least, not easily. You can do pretty much anything with sufficient effort of course. syms X expr = e...

17일 ago | 1

| accepted

Answered

ode45 varargin - additional arguments after options

Long ago and far away, in an age long since past, MATLAB did not have function handles. There were no anonymous functions. There...

ode45 varargin - additional arguments after options

Long ago and far away, in an age long since past, MATLAB did not have function handles. There were no anonymous functions. There...

18일 ago | 0

| accepted

Answered

How to Calculate 100 times the volume of a 3D sphere using Monte Carlo simulation

First, you should already know the volume of a sphere. Is it producing reasonable numbers? If not, then why did you even bother ...

How to Calculate 100 times the volume of a 3D sphere using Monte Carlo simulation

First, you should already know the volume of a sphere. Is it producing reasonable numbers? If not, then why did you even bother ...

19일 ago | 0

| accepted

Answered

generate about 100 random number between 3 to 200 with lognormal disrtibution

A lognormal distribution is not bounded. So you cannot do what you wish to do. It is true however, that you can generate extra ...

generate about 100 random number between 3 to 200 with lognormal disrtibution

A lognormal distribution is not bounded. So you cannot do what you wish to do. It is true however, that you can generate extra ...

19일 ago | 0

Answered

Matlab Eigenvalue/Vector wrong?!

Um, perhaps you misunderstand what eig does, when the matrix is not the usual, Hermitian symmetric matrix. Lsr=[0.0397796877172...

Matlab Eigenvalue/Vector wrong?!

Um, perhaps you misunderstand what eig does, when the matrix is not the usual, Hermitian symmetric matrix. Lsr=[0.0397796877172...

20일 ago | 2

| accepted

Answered

how to work on uncertainty of matrix numbers

This is not as easy as you think it should be, because numbers are not stored in MATLAB in decimal form. As such, what does MATL...

how to work on uncertainty of matrix numbers

This is not as easy as you think it should be, because numbers are not stored in MATLAB in decimal form. As such, what does MATL...

20일 ago | 0

| accepted

Answered

R2015 AND R2018

The simple answer as to the difference is 2018-2015 = 3. If you want a better answer, then you need to do some reading, as ther...

R2015 AND R2018

The simple answer as to the difference is 2018-2015 = 3. If you want a better answer, then you need to do some reading, as ther...

20일 ago | 1

Answered

Help with matrix manipulation

I'm usually harder than Steve is on these things, but I am pretty sure it is not homework. You want to form the sum of those el...

Help with matrix manipulation

I'm usually harder than Steve is on these things, but I am pretty sure it is not homework. You want to form the sum of those el...

21일 ago | 0

| accepted

Answered

Polyfit fitting not work on Matlab

What is it that you think you are doing? Because this seems a bit strange to me. cooefs = [346.355000, -53.3701...

Polyfit fitting not work on Matlab

What is it that you think you are doing? Because this seems a bit strange to me. cooefs = [346.355000, -53.3701...

21일 ago | 0

| accepted

Answered

Create block sparse matrix

Are you asking how to create a block diagonal sparse matrix? Easy peasy. tic N = 100; M = 10000; Z = sparse(rand(N,N*M)); ...

Create block sparse matrix

Are you asking how to create a block diagonal sparse matrix? Easy peasy. tic N = 100; M = 10000; Z = sparse(rand(N,N*M)); ...

22일 ago | 1

Answered

How to generate a random point in the volume of a cylinder

Since you already have an answer posted... Pretty easy, actually. So two points that define the ends of the cylinder, and a know...

How to generate a random point in the volume of a cylinder

Since you already have an answer posted... Pretty easy, actually. So two points that define the ends of the cylinder, and a know...

22일 ago | 2

| accepted