# David Winthrop

MATLAB user for several years. Professional Interests: Image processing,

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**Content Feed**

Strange output from symbolic calculation

I figured out what was going on. It seems the sym interpreter was giving a rational approximation for pi only some of the time. ...

5 months ago | 0

| accepted

Question

Strange output from symbolic calculation

Can someone explain this output (in particular, the numbers) syms f0 T t0 Omegan t n subs(2*f0*pi^2/(Omegan*T*(- Omegan^2*t0^2...

5 months ago | 3 answers | 0

### 3

answersQuestion

How can I get txtscan to read this file?

I tried this but it only seems to have read the first line. There are tabs between columns, I believe. G = textscan(F,'%...

6 months ago | 1 answer | 0

### 1

answerQuestion

How to stop display of variable type in command window?

Hello, When I type >> pi==pi ans = logical 1 I do not want to see the word "logical" there. How can I suppress th...

1 year ago | 1 answer | 0

### 1

answerQuestion

Strange results from unique

I recently encountered a strange result that defies explanation. I took a screenshot. How can this be? <</matlabcentral/answe...

2 years ago | 1 answer | 0

### 1

answerQuestion

Warning('OFF','all') does nothing?

In my code I put: warning('OFF','all') and then I read some images and display them in a figure from within a loop. Every sin...

2 years ago | 0 answers | 0

### 0

answersQuestion

How to extract audio from mp4 video file with Matlab?

I have a video file and I want to extract the video and audio into separate objects for writing to disk separately. I know how ...

2 years ago | 1 answer | 0

### 1

answerQuestion

Option to turn off variable type display

I would like to know how to get rid of the line that tells me what type of variable is. This wasn't there in earlier releases bu...

2 years ago | 1 answer | 0

### 1

answerHow do I get rid of the suggestions/help popup in the command window in Matlab 2014b?

This does not work in R2018a with Ubuntu. Is there anything else that can be done? That little popup window is very annoying!

2 years ago | 1

How to arrainge data to use streamline?

Bumping in the hopes that someone can help.

3 years ago | 0

How to arrainge data to use streamline?

I tried to use griddata but there are some results that MATLAB can't seem to find, such as the re-circulation zones. Here is th...

3 years ago | 0

Question

How to arrainge data to use streamline?

Hello, I have data exported from a finite element software that I want to use in MATLAB to plot streamlines. The format is x...

3 years ago | 3 answers | 0

### 3

answersQuestion

Robust way to calculate volume of a 3D polygon given a triangulation

I am looking for a way to calculate the volume of this shape. I export this shape to a professional finite element software wh...

3 years ago | 0 answers | 0

### 0

answersQuestion

English explanation of the predopt argument to polyconf?

Hello, I am trying to understand the documentation for polyconf and the MATLAB explanation is not clear. It says options other ...

3 years ago | 0 answers | 0

### 0

answersQuestion

Trouble triangulating a surface

I have attached a text file with the data I am discussing. I need to triangulate this data so that I can write the triangulatio...

3 years ago | 0 answers | 0

### 0

answersQuestion

Why is dsolve returning an arbitrary constant?

I have the following differential equation I want to solve from a simple harmonic motion problem. When I enter this into ...

3 years ago | 1 answer | 0

### 1

answerAlternatives to Delaunay triangulation

Thanks everyone! I found a file exchange function that does a very nice job of displaying the mesh so that it matches the mes...

3 years ago | 0

Alternatives to Delaunay triangulation

I have attached the point cloud as a file Coords.txt. Below is the code I use to plot it. I have found that the boundary code wo...

3 years ago | 0

Question

Alternatives to Delaunay triangulation

Hello, I am in need of calculating the volume of a shape that is given as a cloud of points. I thought a first step would be ...

3 years ago | 4 answers | 0

### 4

answersQuestion

Obscure vector function translation from fortran

I have been tasked with translating some code into MATLAB. I am puzzled at this function. It is from a FEA software called ANSYS...

3 years ago | 1 answer | 0

### 1

answerQuestion

How to create a spline for data without sorting?

Hello, I have some data that represents trajectories through the 2D plane. My requirements: I need a pchip type spline to i...

4 years ago | 1 answer | 1

### 1

answerQuestion

Strange error with DAQ

This makes absolutely no sense to me. I recently "upgraded" to r2017b from r2016a on this computer, and now my DAQ doesn't work...

5 years ago | 1 answer | 0

### 1

answerQuestion

MATLAB r2016b problem with cvsread

This makes no sense to me whatsoever. MATLAB will not read the requested data from the file even though it reads the same data ...

5 years ago | 1 answer | 0

### 1

answerQuestion

How can a show the correct view of graphical objects??

I am trying to make an animation, and I noticed that the camera DOES NOT show what it should show. How can I fix this? I mak...

5 years ago | 1 answer | 0

### 1

answerHow can a show the correct view of graphical objects??

Since I have asked this question twice and nobody has commented, I think it is safe to assume nobody knows or it is a bug nobody...

5 years ago | 0

Question

Why don't Axes camera properties seem to work?

I don't understand how the camera properties of the axes work. For example, say I draw a unit circle in the plane and put the c...

5 years ago | 0 answers | 0

### 0

answersQuestion

simulink connecting capacitor problem

I am trying to connect a capacitor in my system and it will not connect to anything. Here is a picture. The wires stay red alw...

8 years ago | 3 answers | 0

### 3

answersQuestion

Why would chol fail?

I have a positive definite sparse array. When I do the chol like L = chol(M,'lower') M2 = (L)*(L.') I find that M...

10 years ago | 0 answers | 0

### 0

answersQuestion

ODE45 to solve non-time function

I would like to use ode45 to solve the following D.E. T'' + (1/x)*T' + G = 0 T'(x=0) = 0 k*T'(x=.5) + h*(T(x=.5) ...

10 years ago | 0 answers | 1