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

Numerically integrate over function that gives out a matrix

While integral offers the option of integrating an array valued function, integral2 does not. However, nothing makes a loop a...

Numerically integrate over function that gives out a matrix

While integral offers the option of integrating an array valued function, integral2 does not. However, nothing makes a loop a...

17 days ago | 0

| accepted

Answered

How can i find the first inersection point of tow functions?

You can't use the intersect function to find the intersection of two curves. Just because the name is similar does not mean it w...

How can i find the first inersection point of tow functions?

You can't use the intersect function to find the intersection of two curves. Just because the name is similar does not mean it w...

18 days ago | 0

| accepted

Answered

Integrating bivariate normal distribution in polar coordinates efficiently

Why do you need to re-express the PDF in polar form? It is one line of code to convert polar form into cartesian form to do the ...

Integrating bivariate normal distribution in polar coordinates efficiently

Why do you need to re-express the PDF in polar form? It is one line of code to convert polar form into cartesian form to do the ...

19 days ago | 0

Answered

How Do I Create/Fix My Code For Collatz Conjecture Using A For Or While Loop?

I'm not sure what assume(x>0) has to do with anything, because you are working with the variable n. But why have you not just...

How Do I Create/Fix My Code For Collatz Conjecture Using A For Or While Loop?

I'm not sure what assume(x>0) has to do with anything, because you are working with the variable n. But why have you not just...

20 days ago | 0

Answered

Power function fitting with my data

Since you have not posted your data, it is difficult to help you very much. But... You can use polyfit to fit the linear curv...

Power function fitting with my data

Since you have not posted your data, it is difficult to help you very much. But... You can use polyfit to fit the linear curv...

20 days ago | 0

| accepted

Answered

ToolBox for Zernike polynomial surface_Fitting

You can find tools for evaluation of Zernike polynomials on the file exchange, here: <https://www.mathworks.com/matlabcentral...

ToolBox for Zernike polynomial surface_Fitting

You can find tools for evaluation of Zernike polynomials on the file exchange, here: <https://www.mathworks.com/matlabcentral...

21 days ago | 0

Answered

Integrating a curve fitted with Sgolay

1. You are not fitting your data using sgolayfilt. All that does is try to reduce the noise in the data, assuming the underlying...

Integrating a curve fitted with Sgolay

1. You are not fitting your data using sgolayfilt. All that does is try to reduce the noise in the data, assuming the underlying...

23 days ago | 0

Answered

How to create a symbolic expression with a string like '5.01e-7*x2 - 5.01e-7 + (-9*x1 + 4)/x1'?

str2sym( '5.01e-7*x2 - 5.01e-7 + (-9*x1 + 4)/x1') ans = 0.000000501*x2 - (9*x1 - 4)/x1 - 0.000000501

How to create a symbolic expression with a string like '5.01e-7*x2 - 5.01e-7 + (-9*x1 + 4)/x1'?

str2sym( '5.01e-7*x2 - 5.01e-7 + (-9*x1 + 4)/x1') ans = 0.000000501*x2 - (9*x1 - 4)/x1 - 0.000000501

23 days ago | 0

| accepted

Answered

Matlab 2018a with parallel computing too slow

Parallel computing need not always gain. Why not? Because MATLAB already automatically does some multi-threading when it thinks ...

Matlab 2018a with parallel computing too slow

Parallel computing need not always gain. Why not? Because MATLAB already automatically does some multi-threading when it thinks ...

23 days ago | 0

Answered

Why is ScatteredInterpolant (linear) returning a value far outside of input data?

You are making a major error here in what you are trying to do. plot3(inX,inY,inZ,'bo') box on grid on Now, rotate...

Why is ScatteredInterpolant (linear) returning a value far outside of input data?

You are making a major error here in what you are trying to do. plot3(inX,inY,inZ,'bo') box on grid on Now, rotate...

23 days ago | 1

| accepted

Answered

How to obtain integer solutions only with fsolve?

Far too late to answer this, but worth explaining how to solve it. Intlinprog, has been suggested is not a viable solution, b...

How to obtain integer solutions only with fsolve?

Far too late to answer this, but worth explaining how to solve it. Intlinprog, has been suggested is not a viable solution, b...

23 days ago | 0

| accepted

Answered

Numerical evaluation of integral gives warning message

Ignoring the fact that you cannot just factor out -1 from that term in the integral, and get what you think you got, we have the...

Numerical evaluation of integral gives warning message

Ignoring the fact that you cannot just factor out -1 from that term in the integral, and get what you think you got, we have the...

25 days ago | 0

Answered

First-order optimality of system of non-linear equations is not converging to 0

A basic presumption of fsolve is that the objective equations to be solved are continuous and differentiable. Your equations ALL...

First-order optimality of system of non-linear equations is not converging to 0

A basic presumption of fsolve is that the objective equations to be solved are continuous and differentiable. Your equations ALL...

25 days ago | 0

Answered

Functions vs scripts: speed

Option B is a REALLY bad programming style. It is slow, as you found out. It prevents MATLAB from optimizing your code for effic...

Functions vs scripts: speed

Option B is a REALLY bad programming style. It is slow, as you found out. It prevents MATLAB from optimizing your code for effic...

25 days ago | 2

Answered

Hot to create a matrix with elements which moves to right as row increases

There are MANY ways to solve this. I'm not at all sure what the final dimension of the matrix is expected to be. Is it 100x100? ...

Hot to create a matrix with elements which moves to right as row increases

There are MANY ways to solve this. I'm not at all sure what the final dimension of the matrix is expected to be. Is it 100x100? ...

25 days ago | 2

| accepted

Answered

Function of the interpolation function

Um, you said interpolation, but you never said what kind of interpolation was used. The crystal ball is very foggy today, so I a...

Function of the interpolation function

Um, you said interpolation, but you never said what kind of interpolation was used. The crystal ball is very foggy today, so I a...

26 days ago | 0

Answered

outputs of generated code are NAN

The crystal ball is so foggy today. Strange, because it is a nice, sunny day here. Sorry, but we cannot read your mind, nor c...

outputs of generated code are NAN

The crystal ball is so foggy today. Strange, because it is a nice, sunny day here. Sorry, but we cannot read your mind, nor c...

26 days ago | 0

Answered

Is it possible to partition a curve and fit it using different funtions

Yes. If you know what you are doing. But that means you need to learn about how to use piecewise functions. You need to learn ab...

Is it possible to partition a curve and fit it using different funtions

Yes. If you know what you are doing. But that means you need to learn about how to use piecewise functions. You need to learn ab...

26 days ago | 0

Answered

Hi.I have been trying a lot to "find" the answer. I still can not get it.

The error? Yours, in making an assumption about floating point arithmetic, and how numbers are stored. x1=(0:0.001:50 )'; ...

Hi.I have been trying a lot to "find" the answer. I still can not get it.

The error? Yours, in making an assumption about floating point arithmetic, and how numbers are stored. x1=(0:0.001:50 )'; ...

26 days ago | 0

Answered

Am I allowed to write functions that have names of matlab functions (copyright)?

I am not a lawyer. But I would argue that it is the code that matters, and the code that has a copyright, which will reside in t...

Am I allowed to write functions that have names of matlab functions (copyright)?

I am not a lawyer. But I would argue that it is the code that matters, and the code that has a copyright, which will reside in t...

27 days ago | 0

Answered

What's the difference between gammainc & igamma? Which one should I use to compute incomplete upper gamma function? Which one is scaled??

igamma lives in the stats toolbox. It gives you an upper tail integral. gammainc lives in MATLAB proper. gammainc is scaled. ...

What's the difference between gammainc & igamma? Which one should I use to compute incomplete upper gamma function? Which one is scaled??

igamma lives in the stats toolbox. It gives you an upper tail integral. gammainc lives in MATLAB proper. gammainc is scaled. ...

27 days ago | 2

| accepted

Answered

How to get a set of elements from a matrix given a set of index pairs?

If you want efficiency, assuming your real problem is much larger, then you need to learn how to use sub2ind. That means you nee...

How to get a set of elements from a matrix given a set of index pairs?

If you want efficiency, assuming your real problem is much larger, then you need to learn how to use sub2ind. That means you nee...

27 days ago | 0

| accepted

Answered

How I generate random numbers with constraints?

This is NOT that hard to do. Yeah, I know it seems hard as hell. The first trick is to build a triangulation that describes t...

How I generate random numbers with constraints?

This is NOT that hard to do. Yeah, I know it seems hard as hell. The first trick is to build a triangulation that describes t...

27 days ago | 0

Answered

I would like to offer a new algorithm to Matlab. Whom should I contact?

Contact nobody. Seriously, just because you have a neat new algorithm, the odds of The MathWorks wanting to add it to the la...

I would like to offer a new algorithm to Matlab. Whom should I contact?

Contact nobody. Seriously, just because you have a neat new algorithm, the odds of The MathWorks wanting to add it to the la...

30 days ago | 3

| accepted

Answered

How to obtain the number of asymptotes from a function handle?

I will suggest what you are lacking is a basic understanding of modeling and statistics. Of the concepts of replication of a dat...

How to obtain the number of asymptotes from a function handle?

I will suggest what you are lacking is a basic understanding of modeling and statistics. Of the concepts of replication of a dat...

30 days ago | 1

Answered

Which one is faster: trace(a' * b) or sum(sum(a .* b', 2))?

Well, I could tell you, but then... Seriously, I cannot tell you, because this is something I cannot know. Nor can anyone els...

Which one is faster: trace(a' * b) or sum(sum(a .* b', 2))?

Well, I could tell you, but then... Seriously, I cannot tell you, because this is something I cannot know. Nor can anyone els...

1 month ago | 1

Answered

Problem In curve fitting

You won't find a function that fits any arbitrary, essentially scattered set of data. And that is what you seem to have. Anyw...

Problem In curve fitting

You won't find a function that fits any arbitrary, essentially scattered set of data. And that is what you seem to have. Anyw...

1 month ago | 0

| accepted

Answered

Simple function constrainting a polyfit with lsqlin is giving strange fits

Is this homework? It seems more sophisticated than the classical homework assignment, so I will guess not. But, sorry, just thro...

Simple function constrainting a polyfit with lsqlin is giving strange fits

Is this homework? It seems more sophisticated than the classical homework assignment, so I will guess not. But, sorry, just thro...

1 month ago | 0

| accepted

Answered

3D interpolating polynomial

Now that you have shown the problem you are trying to solve... I'm pretty sure I remember telling you that you should not use...

3D interpolating polynomial

Now that you have shown the problem you are trying to solve... I'm pretty sure I remember telling you that you should not use...

1 month ago | 0

Answered

I have a 6x6 symbolic matrix A that I want to inverse. I am trying both inv(A) an d A\I to do the inversion. However, it takes forever (more than a day) until I stop it. My hardware is also very good. Core i7, 16 GN RAM.

People think their computers are huge. Super fast. They can do anything. So they get spoiled, expecting anything to work like th...

I have a 6x6 symbolic matrix A that I want to inverse. I am trying both inv(A) an d A\I to do the inversion. However, it takes forever (more than a day) until I stop it. My hardware is also very good. Core i7, 16 GN RAM.

People think their computers are huge. Super fast. They can do anything. So they get spoiled, expecting anything to work like th...

1 month ago | 1