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

Solving non linear equations sytem

I would reduce this to a 2 variable problem first. That is, use equation 1 to solve for x1. x1 = b1/cos(a1 + x2) Likewise,...

Solving non linear equations sytem

I would reduce this to a 2 variable problem first. That is, use equation 1 to solve for x1. x1 = b1/cos(a1 + x2) Likewise,...

ungefär 4 timmar ago | 1

Answered

sparse to gridded 3-D interpolation

First, should MATLAB use all of the CPU capability? That is difficult in what you are doing, becaue it is not easily parallelize...

sparse to gridded 3-D interpolation

First, should MATLAB use all of the CPU capability? That is difficult in what you are doing, becaue it is not easily parallelize...

ungefär 7 timmar ago | 0

Answered

Regularization for Non-linear fitting with fitnlm.

(Please don't add answers to make a comment. Use comments for that.) But how can you do a simple regularization on the coeffici...

Regularization for Non-linear fitting with fitnlm.

(Please don't add answers to make a comment. Use comments for that.) But how can you do a simple regularization on the coeffici...

ungefär 13 timmar ago | 1

Answered

185k1*185k Matrix

Think of it like this: If all of the elements in that matrix are non-zeros, then you have 185000^2 ans = 3.4225e+10 So 3...

185k1*185k Matrix

Think of it like this: If all of the elements in that matrix are non-zeros, then you have 185000^2 ans = 3.4225e+10 So 3...

ungefär 22 timmar ago | 0

Answered

A function to find prime number

Hey, you wrote some code! Credit for that. :-) But what did you do? function isPrime(number) tf=isprime(number); if tf==tru...

A function to find prime number

Hey, you wrote some code! Credit for that. :-) But what did you do? function isPrime(number) tf=isprime(number); if tf==tru...

en dag ago | 0

Answered

Question about the tolerance of lsqcurvefit

This is not a problem of lsqcurvefit tolerance. Instead, see that the error makes a statement about INTEGRATION tolerances. That...

Question about the tolerance of lsqcurvefit

This is not a problem of lsqcurvefit tolerance. Instead, see that the error makes a statement about INTEGRATION tolerances. That...

en dag ago | 0

Answered

I am trying to integrate IMU and GPS data to find roll of ground vehicle on the same road at different velocities. But, I am getting inconsistent results and an error at higher velocities (45mph) compared to lower velocities(25mph).

The singular matrix suggests why it is you are getting garbage, as once you have that, nothing will likely make any sense. Is th...

I am trying to integrate IMU and GPS data to find roll of ground vehicle on the same road at different velocities. But, I am getting inconsistent results and an error at higher velocities (45mph) compared to lower velocities(25mph).

The singular matrix suggests why it is you are getting garbage, as once you have that, nothing will likely make any sense. Is th...

en dag ago | 0

Answered

Linspace with varying increment

The problem is, vendor provided software cannot work like that. You have descibed several cases of potential interest to you, fr...

Linspace with varying increment

The problem is, vendor provided software cannot work like that. You have descibed several cases of potential interest to you, fr...

2 dagar ago | 1

Answered

Linear Constraint based on two variables fmincon

Why, if you already have other inequality constraints, is this a question? And how you wrote it, using A is inconsistent with yo...

Linear Constraint based on two variables fmincon

Why, if you already have other inequality constraints, is this a question? And how you wrote it, using A is inconsistent with yo...

2 dagar ago | 1

Answered

I need to solve an equation involving squares and cubes.

You have many values for both d and p? Do you want to solve it for all combinations of d and p? Anyway, first, I would recogniz...

I need to solve an equation involving squares and cubes.

You have many values for both d and p? Do you want to solve it for all combinations of d and p? Anyway, first, I would recogniz...

2 dagar ago | 0

Answered

decrease calculation accuracy to speed up running time

You essentially cannot do what you want, with one small caveat. That is, you canot arbitrarily tell MATLAB to do all computation...

decrease calculation accuracy to speed up running time

You essentially cannot do what you want, with one small caveat. That is, you canot arbitrarily tell MATLAB to do all computation...

2 dagar ago | 3

Answered

how to plot an ellipse having her equation?

First, learn how to write a function. fun = @(x,y) x.^2 / 25 + y.^2 / 9 - 1; Note the use of the .^ operators. They will be im...

how to plot an ellipse having her equation?

First, learn how to write a function. fun = @(x,y) x.^2 / 25 + y.^2 / 9 - 1; Note the use of the .^ operators. They will be im...

3 dagar ago | 0

Answered

Unable to predict data well enough

I would point out that your code shows you using the first SEVEN data points, not the first 10, despite your claim otherwise. n...

Unable to predict data well enough

I would point out that your code shows you using the first SEVEN data points, not the first 10, despite your claim otherwise. n...

3 dagar ago | 0

Answered

how can i find the intersection point between the vertical lines and the curve (xmin,ymin) ?

The red curve is a piecewise linear interpolation, not really a curve, just connect the dots by the plotting routine. The green...

how can i find the intersection point between the vertical lines and the curve (xmin,ymin) ?

The red curve is a piecewise linear interpolation, not really a curve, just connect the dots by the plotting routine. The green...

3 dagar ago | 1

| accepted

Answered

lsqcurvefit: is the output of this function unique for a given set of initial conditions (and deterministic model)?

The problem is, that is not your code. Not all of it. That is just how you call lsqcurvefit. We do not see the pandemic1Dall2 co...

lsqcurvefit: is the output of this function unique for a given set of initial conditions (and deterministic model)?

The problem is, that is not your code. Not all of it. That is just how you call lsqcurvefit. We do not see the pandemic1Dall2 co...

3 dagar ago | 1

Answered

change a logical array value based on the index of another matrix

If you want to create x on the fly, then just do this: x = A > 4; If you for some reason really want to modify an existing vec...

change a logical array value based on the index of another matrix

If you want to create x on the fly, then just do this: x = A > 4; If you for some reason really want to modify an existing vec...

4 dagar ago | 0

| accepted

Answered

What's the meaning of instrucment sound in Matlab?

Let me just answer this as if you asked for an explanation of what a sound is in the world of MATLAB. For example, if we try: l...

What's the meaning of instrucment sound in Matlab?

Let me just answer this as if you asked for an explanation of what a sound is in the world of MATLAB. For example, if we try: l...

5 dagar ago | 0

Answered

vector to upper and lower triangular matrix

What you fail to see is that while your code works for a 3x3 matrrix, it must always fail for any n other than n==3. You want t...

vector to upper and lower triangular matrix

What you fail to see is that while your code works for a 3x3 matrrix, it must always fail for any n other than n==3. You want t...

5 dagar ago | 0

| accepted

Answered

double differentiation and double integration of sine wave

This is not a question about MATLAB, just understanding some basic mathematics. At least, understanding calc 101. First, you ne...

double differentiation and double integration of sine wave

This is not a question about MATLAB, just understanding some basic mathematics. At least, understanding calc 101. First, you ne...

5 dagar ago | 0

Answered

Diagonal/Symmetric matrix

I don't even think your code works for a 3x3 matrix. The matrix it produces is OD OD = 81 23 18....

Diagonal/Symmetric matrix

I don't even think your code works for a 3x3 matrix. The matrix it produces is OD OD = 81 23 18....

5 dagar ago | 0

| accepted

Answered

How do I open a pcode (.p) file created in a version older than MATLAB R2007b? My Matlab version is R2018b.

You cannot edit a .p file, if that is what you mean by open. That is true in any version. If the .p file is too old, but you s...

How do I open a pcode (.p) file created in a version older than MATLAB R2007b? My Matlab version is R2018b.

You cannot edit a .p file, if that is what you mean by open. That is true in any version. If the .p file is too old, but you s...

7 dagar ago | 0

Answered

How to transfer a Matlab toolbox I have in my machine to the machine of a colleague ?

If this is a toolbox that you have purchased from Mathworks, you cannot give it to someone else. If this is a toolbox you have ...

How to transfer a Matlab toolbox I have in my machine to the machine of a colleague ?

If this is a toolbox that you have purchased from Mathworks, you cannot give it to someone else. If this is a toolbox you have ...

7 dagar ago | 0

Answered

For loop for matrix division

Why would you want to use any loop at all? For example, if A is an mxn matrix, and V is a vector of size mx1, then consider what...

For loop for matrix division

Why would you want to use any loop at all? For example, if A is an mxn matrix, and V is a vector of size mx1, then consider what...

7 dagar ago | 0

Answered

Can someone explain the concept of B= null(A) in simple words?

Think of A as a vector pointing someplace in a 5 dimensional space. Got that? It points somewhere. Now, in 5 dimensions, we co...

Can someone explain the concept of B= null(A) in simple words?

Think of A as a vector pointing someplace in a 5 dimensional space. Got that? It points somewhere. Now, in 5 dimensions, we co...

8 dagar ago | 1

| accepted

Answered

How to get more decimal places in my output?

In fact, it does NOT neglect that term. It is in there, just too small for you to see in only 4 decimal places. help format Yo...

How to get more decimal places in my output?

In fact, it does NOT neglect that term. It is in there, just too small for you to see in only 4 decimal places. help format Yo...

8 dagar ago | 1

Answered

How to remove last characters from String using mod?

It is generally a bad idea to use names for variables that are already useful function names. So here rem is one such bad idea. ...

How to remove last characters from String using mod?

It is generally a bad idea to use names for variables that are already useful function names. So here rem is one such bad idea. ...

10 dagar ago | 2

| accepted

Answered

Random sampling of elements from an array based on a target condition in MATLAB

Are you looking for an exact match to V1? An approximate sum equal to V1? If so, then how close of a tolerance do you need? Is ...

Random sampling of elements from an array based on a target condition in MATLAB

Are you looking for an exact match to V1? An approximate sum equal to V1? If so, then how close of a tolerance do you need? Is ...

10 dagar ago | 1

Answered

how to use large numbers

Depending on what you are doing, you can use any of several tools. For example ... The symbolic toolbox: sym(17)^173 ans = 7...

how to use large numbers

Depending on what you are doing, you can use any of several tools. For example ... The symbolic toolbox: sym(17)^173 ans = 7...

10 dagar ago | 1

| accepted

Answered

is max built in functions

Yes. max is definitely a built-in function. As such, use of it will have been (sadly) outlawed by your assignment.

is max built in functions

Yes. max is definitely a built-in function. As such, use of it will have been (sadly) outlawed by your assignment.

11 dagar ago | 0

| accepted

Answered

Calling a multivariable system of equations

I think you do not understand functions. And, well, I suppose this is a not uncommon problem for new users. There are at least t...

Calling a multivariable system of equations

I think you do not understand functions. And, well, I suppose this is a not uncommon problem for new users. There are at least t...

12 dagar ago | 0