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

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 day 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...

2 days 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...

3 days 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...

3 days ago | 1

Answered

Finding x such that 1 is eigenvalue

You are trying to do too much in one line. Making your code super compact does nothing, except make it unreadable. And it did no...

Finding x such that 1 is eigenvalue

You are trying to do too much in one line. Making your code super compact does nothing, except make it unreadable. And it did no...

4 days ago | 0

| accepted

Answered

exp*prod*exp(x(lnx)^k) solving equation

Read what I said. Again. TAKE THE LOG!!!!!!! That gives you something like this: -lambda*pi*r^2*P + lambda*pi*R^2*P*(log(P)...

exp*prod*exp(x(lnx)^k) solving equation

Read what I said. Again. TAKE THE LOG!!!!!!! That gives you something like this: -lambda*pi*r^2*P + lambda*pi*R^2*P*(log(P)...

5 days ago | 1

| accepted

Answered

Does interp3 (with linear option) perform trilinear interpolation?

Both interp2 and interp3 use n-dimensional tensor product linear interpolation, thus respectively bilinear and trilinear interpo...

Does interp3 (with linear option) perform trilinear interpolation?

Both interp2 and interp3 use n-dimensional tensor product linear interpolation, thus respectively bilinear and trilinear interpo...

6 days ago | 1

| accepted

Answered

Order of roots obtained from function roots

Roots does not assure any specific order of the returned roots, nor should it rationally do so. Feel free to sort them in any...

Order of roots obtained from function roots

Roots does not assure any specific order of the returned roots, nor should it rationally do so. Feel free to sort them in any...

7 days ago | 0

| accepted

Answered

Find tangent to set of 2D points

Your curve is somewhat noisy. I might think to point out that my interparc tool from the file exchange can be made to give estim...

Find tangent to set of 2D points

Your curve is somewhat noisy. I might think to point out that my interparc tool from the file exchange can be made to give estim...

7 days ago | 2

| accepted

Answered

How can I set limits to an interpolation with griddata?

You cannot set limits when using griddata, AND the 'cubic' option. It will happily interpolate smoothly as it will. But that may...

How can I set limits to an interpolation with griddata?

You cannot set limits when using griddata, AND the 'cubic' option. It will happily interpolate smoothly as it will. But that may...

7 days ago | 0

| accepted

Answered

Is any way to Inpaint this image?

I won't touch this, and I've written the main inpainting tool on the File Exchange. Do NOT use that tool I've posted, as you wil...

Is any way to Inpaint this image?

I won't touch this, and I've written the main inpainting tool on the File Exchange. Do NOT use that tool I've posted, as you wil...

8 days ago | 0

Answered

How to seperate a matrix into several parts and give names each of them?

Don't do it. There are MANY better ways to solve this. For example, convert your vector (via a simple reshape) into an array....

How to seperate a matrix into several parts and give names each of them?

Don't do it. There are MANY better ways to solve this. For example, convert your vector (via a simple reshape) into an array....

8 days ago | 0

Answered

skipping code sections when running the code

If this is a script, then learn how to use cell mode. Learn about live scripts. If this is a function, then learn to write...

skipping code sections when running the code

If this is a script, then learn how to use cell mode. Learn about live scripts. If this is a function, then learn to write...

8 days ago | 0

Answered

Best computer for problem

Which specific computer should you get? One as fast as your company will pay for, with the most RAM they will go for. Make sure ...

Best computer for problem

Which specific computer should you get? One as fast as your company will pay for, with the most RAM they will go for. Make sure ...

9 days ago | 1

Answered

How to solve algebraic equations in Matlab 2018a？

In R2018a, they finally stopped letting you just provide a string input. It has been something they have been threatening for se...

How to solve algebraic equations in Matlab 2018a？

In R2018a, they finally stopped letting you just provide a string input. It has been something they have been threatening for se...

9 days ago | 1

| accepted

Answered

Finding value of unknown variable in determinant matrix, where matrix is kept equal to zero

The .jpg you show is a 3x3 matrix, NOT a 6x6 matrix. So there are obvious points of confusion in what you say. But in any case, ...

Finding value of unknown variable in determinant matrix, where matrix is kept equal to zero

The .jpg you show is a 3x3 matrix, NOT a 6x6 matrix. So there are obvious points of confusion in what you say. But in any case, ...

9 days ago | 0

Answered

Increase performance for null space calculation on symbolic matrix

Surely you need to recognize the difficulties here. If not, then you need to consider what is involved. Let me give a trivia...

Increase performance for null space calculation on symbolic matrix

Surely you need to recognize the difficulties here. If not, then you need to consider what is involved. Let me give a trivia...

10 days ago | 1

Answered

How do I find the mean of all the radius around a point in polar coordinates?

Are you asking how to find the mean of ALL pixels that lie WITHIN a radius of R, of some fixed point in the image? If so, the...

How do I find the mean of all the radius around a point in polar coordinates?

Are you asking how to find the mean of ALL pixels that lie WITHIN a radius of R, of some fixed point in the image? If so, the...

10 days ago | 1

| accepted

Answered

curve fit exactly the function I enter

So why do you think that a sum of two exponentials MUST fit this data? Looking at the data, that hardly seems a good conclusion....

curve fit exactly the function I enter

So why do you think that a sum of two exponentials MUST fit this data? Looking at the data, that hardly seems a good conclusion....

10 days ago | 0

| accepted

Answered

problems with a trascendental equation

You probably need to start with the basic tutorials to learn MATLAB. For example, you do this: m = linspace(10,20,1) m =...

problems with a trascendental equation

You probably need to start with the basic tutorials to learn MATLAB. For example, you do this: m = linspace(10,20,1) m =...

10 days ago | 1

Answered

How do I set an inline function as a parameter?

I assume you want to pass in a function to be used in your bisection code? First, don't use inline functions, unless your MAT...

How do I set an inline function as a parameter?

I assume you want to pass in a function to be used in your bisection code? First, don't use inline functions, unless your MAT...

11 days ago | 1

Answered

How to combine series of consecutive numbers in Matlab?

Loops are not terrible things, to be feared in MATLAB. Yes, it is true that often you can gain in speed by replacing nested loop...

How to combine series of consecutive numbers in Matlab?

Loops are not terrible things, to be feared in MATLAB. Yes, it is true that often you can gain in speed by replacing nested loop...

13 days ago | 2

Answered

Does different MATLAB versions handle array arithmetic differently ?

In R2016 (not sure if it was a or b. I think b, but not really relevant, so will not check.) they introduced the capability to e...

Does different MATLAB versions handle array arithmetic differently ?

In R2016 (not sure if it was a or b. I think b, but not really relevant, so will not check.) they introduced the capability to e...

13 days ago | 0

Answered

same matrix but not equal problem

When you see something that you do not understand, LOOK AT YOUR DATA. C(1,:) ans = Columns 1 through 31 NaN ...

same matrix but not equal problem

When you see something that you do not understand, LOOK AT YOUR DATA. C(1,:) ans = Columns 1 through 31 NaN ...

13 days ago | 0

| accepted

Answered

Finding coefficients from factorized polynomial?

I have no idea what you are talking about. n = 3; syms x y z = (x+y)^n; c = coeffs(z) c = [ 1, 3, 3, 1] I...

Finding coefficients from factorized polynomial?

I have no idea what you are talking about. n = 3; syms x y z = (x+y)^n; c = coeffs(z) c = [ 1, 3, 3, 1] I...

13 days ago | 0

| accepted

Answered

solving system of equations using singular value decomposition and fsolve

Solving a singular (or nearly so) linear system of equations will have infinitely many solutions, all equally good (or bad). ...

solving system of equations using singular value decomposition and fsolve

Solving a singular (or nearly so) linear system of equations will have infinitely many solutions, all equally good (or bad). ...

14 days ago | 0

| accepted

Answered

Solve command in matlab not working?

The problem is not in solve. It is with your understanding of the mathematics. You wrote this: N1 = 76.045376620772100, ...

Solve command in matlab not working?

The problem is not in solve. It is with your understanding of the mathematics. You wrote this: N1 = 76.045376620772100, ...

14 days ago | 1

Answered

if statement for error

No. You cannot use if to find an error, because an error interrupts and stops execution of your code. However, you can use a try...

if statement for error

No. You cannot use if to find an error, because an error interrupts and stops execution of your code. However, you can use a try...

14 days ago | 0

| accepted

Answered

How do I create a solid shape that has a smaller area on the bottom surface than the top surface?

Hmm. But not hard in any case. Best if the top and bottom polggons are the same length. Suppose we create two polygons. If th...

How do I create a solid shape that has a smaller area on the bottom surface than the top surface?

Hmm. But not hard in any case. Best if the top and bottom polggons are the same length. Suppose we create two polygons. If th...

14 days ago | 0

Answered

Does MatLab run on Debian 9?

The answer to these questions is always easy and fast. Just check the system requirements. https://www.mathworks.com/support/...

Does MatLab run on Debian 9?

The answer to these questions is always easy and fast. Just check the system requirements. https://www.mathworks.com/support/...

14 days ago | 1