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

optimum conditions - fitlm

No, you have not depicted any curve or surface. You may think you attached something, but you did not. Do you see anything attac...

optimum conditions - fitlm

No, you have not depicted any curve or surface. You may think you attached something, but you did not. Do you see anything attac...

12 hours ago | 0

Answered

Can I use the minimax optimization algorithm for multiple variables?

If your goal is to set thresholds which are then used to group your data into subgroups, the answer is no. Sorry. Why? Think ...

Can I use the minimax optimization algorithm for multiple variables?

If your goal is to set thresholds which are then used to group your data into subgroups, the answer is no. Sorry. Why? Think ...

17 hours ago | 0

Answered

how do i explain which eigenvector the software reports as there are theoretically an infinite number?

Return to linear algebra 101. Do not pass go, do not collect $200. Really, if you will be using tools like eig, it would be good...

how do i explain which eigenvector the software reports as there are theoretically an infinite number?

Return to linear algebra 101. Do not pass go, do not collect $200. Really, if you will be using tools like eig, it would be good...

18 hours ago | 0

Answered

Why am I getting images that are less exposed than they should be based on my settings?

I will bet that when you set everything to manual mode, you get a raw image, as it comes directly from the sensor. When you let ...

Why am I getting images that are less exposed than they should be based on my settings?

I will bet that when you set everything to manual mode, you get a raw image, as it comes directly from the sensor. When you let ...

20 hours ago | 0

Answered

Is there a simple way to rotate a matrix 45 degrees? (like rot90)

No. Your plan completely fails for 2x2 matrices, or for any even size matrix at all. As well, it also fails for matrices larger ...

Is there a simple way to rotate a matrix 45 degrees? (like rot90)

No. Your plan completely fails for 2x2 matrices, or for any even size matrix at all. As well, it also fails for matrices larger ...

20 hours ago | 1

Answered

matlab code erro massage where ~ used

The problem is you took some code for a newer MATLAB release than you have. So the answer is to get a more recent version of MAT...

matlab code erro massage where ~ used

The problem is you took some code for a newer MATLAB release than you have. So the answer is to get a more recent version of MAT...

1 day ago | 0

Answered

det(x) is non zero

It is time for you to learn what are floating point numbers. Also, why det is a dangerous thing to use in general. det is com...

det(x) is non zero

It is time for you to learn what are floating point numbers. Also, why det is a dangerous thing to use in general. det is com...

3 days ago | 1

Answered

How to access zero index in the following code?

Do you mean that you cannot use an if test? It is not possible to test for when i==1, and use a slightly different formula? Hmm....

How to access zero index in the following code?

Do you mean that you cannot use an if test? It is not possible to test for when i==1, and use a slightly different formula? Hmm....

3 days ago | 0

| accepted

Answered

Sine Regression with NonLinearModel.fit

You are making the mistake of providing poor starting values. You simply needed to provide a set of more intelligent starting va...

Sine Regression with NonLinearModel.fit

You are making the mistake of providing poor starting values. You simply needed to provide a set of more intelligent starting va...

3 days ago | 0

| accepted

Answered

Optimization problem with 2 unknowns

In terms of the optimization, you don't have TWO variables. You have two unknown matrices, containing 933*2488+933*933 total unk...

Optimization problem with 2 unknowns

In terms of the optimization, you don't have TWO variables. You have two unknown matrices, containing 933*2488+933*933 total unk...

4 days ago | 0

Answered

How can I find the mixed partial derivatives using Matlab?

You would differentiate with respect to y twice, so the second derivative, and once with respect to x. Essentially two calls to ...

How can I find the mixed partial derivatives using Matlab?

You would differentiate with respect to y twice, so the second derivative, and once with respect to x. Essentially two calls to ...

5 days ago | 0

Answered

Hi, everyone i have an array of 500 random values i want to plot a pdf from this kindly help me. I am uploading array file.

help hist Though, it will probably be rather a waste of time. hist(T_Ag,100) <</matlabcentral/answers/uploaded_file...

Hi, everyone i have an array of 500 random values i want to plot a pdf from this kindly help me. I am uploading array file.

help hist Though, it will probably be rather a waste of time. hist(T_Ag,100) <</matlabcentral/answers/uploaded_file...

5 days ago | 0

| accepted

Answered

how i can return the index of an array?

Time to read the manual, given a basic problem. Either of these tools will do what you want: help find help ismember

how i can return the index of an array?

Time to read the manual, given a basic problem. Either of these tools will do what you want: help find help ismember

5 days ago | 1

| accepted

Answered

Calculate t maximums in single vector

Sort them. Then take the first 5 elements from the sort. WTP? No. It is not ONE single command. Not an option. Of course, not...

Calculate t maximums in single vector

Sort them. Then take the first 5 elements from the sort. WTP? No. It is not ONE single command. Not an option. Of course, not...

5 days ago | 0

Answered

solving trigonometrique equation ?

You will never get an analytical result here. vpasolve(g1) ans = -0.04489097131344154920928045475445

solving trigonometrique equation ?

You will never get an analytical result here. vpasolve(g1) ans = -0.04489097131344154920928045475445

5 days ago | 0

Answered

Why I get different results evaluating the same matrix usign the symbolic toolbox and the numerical approach?

Simple. Because the symbolic TB uses higher precision arithmetic than does double. On some problems this matters. As well, the s...

Why I get different results evaluating the same matrix usign the symbolic toolbox and the numerical approach?

Simple. Because the symbolic TB uses higher precision arithmetic than does double. On some problems this matters. As well, the s...

6 days ago | 0

Answered

How can I plot a correct fft of cosine wave?

What did you plot? Hint: look at the code you wrote: k=0:fs:11*fs; stem(k,y) What is plotted as the x axis? The numbe...

How can I plot a correct fft of cosine wave?

What did you plot? Hint: look at the code you wrote: k=0:fs:11*fs; stem(k,y) What is plotted as the x axis? The numbe...

6 days ago | 0

Answered

Curve fitting: Difference fit, nlinfit, fitlnm

The differences are simple. These tools mainly come from different toolboxes. That is really the main difference. Curve fitting ...

Curve fitting: Difference fit, nlinfit, fitlnm

The differences are simple. These tools mainly come from different toolboxes. That is really the main difference. Curve fitting ...

6 days ago | 0

| accepted

Answered

Curve fitting: What does LAR do?

I don't understand what is confusing. The sum of the absolute values of the residuals is clearly NOT least squares, thus a minim...

Curve fitting: What does LAR do?

I don't understand what is confusing. The sum of the absolute values of the residuals is clearly NOT least squares, thus a minim...

6 days ago | 1

| accepted

Answered

how can I get matlab/simulink contain thermodynamics libraly?

Start writing. Nobody can give you code from toolboxes that you do not own. Or upgrade your copy of MATLAB (and the correspon...

how can I get matlab/simulink contain thermodynamics libraly?

Start writing. Nobody can give you code from toolboxes that you do not own. Or upgrade your copy of MATLAB (and the correspon...

7 days ago | 0

Answered

Undefined function or variable f when using solve function

Did you ever tell MATLAB in advance that f is a symbolic variable? help syms

Undefined function or variable f when using solve function

Did you ever tell MATLAB in advance that f is a symbolic variable? help syms

7 days ago | 0

Answered

Measure whether two curves are significantly different from each other

I'll argue that you cannot assign any statistical significance to the difference between two sets of points as curves, when you ...

Measure whether two curves are significantly different from each other

I'll argue that you cannot assign any statistical significance to the difference between two sets of points as curves, when you ...

7 days ago | 0

Answered

Command "cluster" with big data: it used to work fast but now it works slow

Since we have absolutely nothing to go on about the actual data, I can only guess. Clustering tools usually use random starts...

Command "cluster" with big data: it used to work fast but now it works slow

Since we have absolutely nothing to go on about the actual data, I can only guess. Clustering tools usually use random starts...

7 days ago | 0

Answered

Is there a quick way to calculate rank of a binary sequence?

For any vector of length N, most of the matrices you would try to form are not even validly rectangular matrices. Thus for a vec...

Is there a quick way to calculate rank of a binary sequence?

For any vector of length N, most of the matrices you would try to form are not even validly rectangular matrices. Thus for a vec...

8 days ago | 0

Answered

Why does it take forever to solve my optimization problem (using ode45 and fmincon)?

How can we know what you did that now causes the problem? Since we do not see your code, we cannot read your mind. You changed s...

Why does it take forever to solve my optimization problem (using ode45 and fmincon)?

How can we know what you did that now causes the problem? Since we do not see your code, we cannot read your mind. You changed s...

9 days ago | 0

Answered

Question about a Logistic Equation

You are correct that Nrab is the problem. You need to learn about the element-wise operations, {.* ./ .^} , all designed to hand...

Question about a Logistic Equation

You are correct that Nrab is the problem. You need to learn about the element-wise operations, {.* ./ .^} , all designed to hand...

9 days ago | 0

| accepted

Answered

Is there a way to manually input an objective function value to find the next iteration x values?

What do you mean that it is built into MATLAB? No, PSO tools are NOT part of MATLAB proper. There are PSO toolboxes you can down...

Is there a way to manually input an objective function value to find the next iteration x values?

What do you mean that it is built into MATLAB? No, PSO tools are NOT part of MATLAB proper. There are PSO toolboxes you can down...

10 days ago | 0

Answered

converting .001 .002 file

Get a list of all the files. dir will do that. help dir Then, rename each file, using a loop over the files. Just create...

converting .001 .002 file

Get a list of all the files. dir will do that. help dir Then, rename each file, using a loop over the files. Just create...

10 days ago | 0

Answered

Problem with polyfit and polyval

You start off doing a bad thing in these two lines:. GFit = polyfit(Freq,G,length(Freq)); PhaseFit = polyfit(Freq,Phase,...

Problem with polyfit and polyval

You start off doing a bad thing in these two lines:. GFit = polyfit(Freq,G,length(Freq)); PhaseFit = polyfit(Freq,Phase,...

11 days ago | 1