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Walter Roberson


Last seen: Today Active since 2011

I do not do free private consulting. If you want to bring my attention to something, send a link to the MATLAB Answers location. I am currently caught up to T0099119; if you are waiting on a reply from me for an older issue, please send me a reminder.

Programming Languages:
C, MATLAB, Shell, Perl, Fortran
Spoken Languages:
English

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Answered
Is there a way to reduce Timer period to less than 1 ms?
You would need to reimplement timers.

6 hours ago | 0

Answered
Find doesn't seem to work with Matrix larger than 127x127
I am certain that find works. I speculate that you are putting the values together in an array with values of datatype int8. Whe...

7 hours ago | 2

| accepted

Answered
Accessing the url address of images in Matlab Drive
The files on matlab drive cannot be remotely accessed individually. Even if you publicly share a folder, the share mechanisms do...

7 hours ago | 0

Answered
How can I find the Time for specific values of Voltage (with a small tolerance)?
find(abs(data-target)<=tolerance) Or ismembertol()

8 hours ago | 0

Answered
I would like to extract x,y,z coordinates of any 3 atoms from a pdb file. How to rectify this error and make it generalized?
% N = range of indices for example N=1:7; Q = [ubq.Model.Atom(N).X; ubq.Model.Atom(N).Y; ubq.Model.Atom(n).Z].'; This...

18 hours ago | 1

Answered
Dynamic plot in real time
pick nominal x coordinates for the endpoints of the see-saw. Create a line that has those as the x coordinates and has the "curr...

18 hours ago | 0

Answered
Error: File: project_01.m Line: 61 Column: 26
elseif Hexa_number_small = Hexa_row_small * (Hexa_number - 1); elseif must be followed by a condition, not an assignment.

18 hours ago | 0

Answered
Error in ode45 (line 115) odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
delta = 1; That is a numeric scalar. Valid indices for it are numeric 1, logical true, logical false, and the empty vector....

19 hours ago | 0

Answered
Why do I get unrecognized function or variable when calling constructor in app designer
TFeature is not a property or method of the class, and it does not exist at the time the properties list is being parsed. It is ...

1 day ago | 0

Answered
saving figures to a video with VideoWriter
getframe() with no options is not guaranteed to return the same size each time. In practice the size of an axes can vary by (if ...

1 day ago | 0

Answered
How can I specify the dimension of a differentiated function?
diff() is generally successive differences. It is only derivative if the first parameter is sym or symfun, both from the Symboli...

1 day ago | 0

Answered
Finding a redundant pattern in a matrix
C1=[ 5 9 3]; C2=[ 9 5 3]; C3=[9 5 9 3]; C4=[5 9 8 3]; C5 = [5 3 9 8]; is_in(C1, C2) is_in(C1, C3) is_in(C1, C4) is_in(C1, ...

2 days ago | 0

Answered
Connecting to USB device with serialport vs. serial command
serialport does not have any fopen() or fread() . It automatically opens the port when you create the object, and it uses read()...

2 days ago | 0

Answered
Empty matrix, scalar, or vector function in loop
MATLAB uses == for comparisons, not = Also, X = [] Y = 1 if X == []; disp('X yes 1'); end if Y == []; disp('Y yes 1'); end ...

2 days ago | 0

Answered
Numeric data becomes zero after conversion from Table
I predict that you have format short in effect, and that what is being displayed is not really 0 but is instead something of t...

2 days ago | 0

| accepted

Answered
Why results of the 'solve' are wrong?
p_max=715.685424949238; (and a bunch of other numbers). What does that input mean? Does it mean that p_max is exactly ? Does ...

2 days ago | 1

| accepted

Answered
Excel sheet data upload "Invalid 'DataRange'. The column size must match the number of variables".
opts.DataRange = "A2:AT78"; That requests that column "A" to "AT" be read in. However, M1_New_Macro1.xlsx only has data up to c...

2 days ago | 1

Answered
Logical operator not evaluating correctly
A|B is an or test and returns a logical value -1 is nonzero which is considered true, and since you or everything together you a...

2 days ago | 0

Answered
Hi.How I can plot W_m to n connection
See <https://www.fieggen.com/shoelace/lacingmethods.htm> for some of the possible ways to plot that.

3 days ago | 0

Answered
Receiving mouse clicks in App Designer UIAxes - stops working after imshow
https://www.mathworks.com/help/matlab/creating_plots/capturing-mouse-clicks.html MATLAB considers graphics objects to be layer...

3 days ago | 0

| accepted

Answered
molecular code in matlab
There are a lot of undefined variables there. There are two possibilities: There might be another script that you have to exec...

3 days ago | 0

Answered
Need help coding this
Example. fun = @(x, y) (x + y).^3 - 5*(x.*y) - 1; [X, Y] = meshgrid( linspace(0,2)); z = fun(X, Y); contour(X, Y, z);

3 days ago | 0

Answered
I have a data 5x148992 , i have to extract data column wise and check if there is any changes wrt previous column and display when there are chnages?
for i = (data( : , : )) data appears to be a 2D array. When you have something of the form for VARIABLE = EXPRESSION; BODY;...

3 days ago | 0

| accepted

Answered
How to add Line/Markers to an Axis Label?
L = "G\prime ( \bullet ) and G\prime\prime ( \color{red}{\bullet}\color{black} ) (Pa)"; ylabel(L, 'interpreter', 'tex') See al...

3 days ago | 0

| accepted

Answered
How to calculate the symbolic integration of rational functions?
Wolfram Alpha says https://www.wolframalpha.com/input?i=int%281%2F%28x%5E4+%2B+x%5E3+%2B+x%5E2+%2B+x+%2B+1%29%2C+x%2C+0%2C+1%29&...

3 days ago | 0

Answered
Solving large linear systems of equations in parallel / distributed systems
Gb = 60000^2*8/1024^3 The matrix is close to 27 gigabytes. The inverse is the same size, so you will need at least 54 gigabytes...

3 days ago | 0

Answered
How to make a new column in my table
elseif requires a expression after it, but you coded an assignment. You just want else not elseif Remember that if Results(...

3 days ago | 0

Answered
Need a to plot a graph
hvals = linspace(0,17); numh = length(hvals); Vtotal = zeros(numh, 1); H1 = 11; %in H2 = 5; %in m r1 = 3.5; %in m r2 = ...

3 days ago | 0

Answered
Trial download 2021b
only Mathworks Sales can generate trials against older versions.

4 days ago | 1

Answered
How to shift elements in matrix?
circshift()

4 days ago | 0

| accepted

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