Community Profile # 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 T0099000; if you are waiting on a reply from me for an older issue, please send me a reminder.

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

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griddata command returns all NaN values
for a = 1:100 X1(a) = (5/100).*a; X1 is linear in a. c = a/50; a is a double precision integer, 1 to 100. c is the inte...

ungefär 7 timmar ago | 0

Sending four byte commands To serial port
cmd = [0x81 0x12 0x00 0x00]; write(YourPortObject, cmd, 'uint8'); response = read(YourSerialPortObject, 4, 'uint8'); if ise...

ungefär 7 timmar ago | 0

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Integer eigenvalues in Matlab
Take the symbolic determinant of (matrix minus lambda) . Ask to factor() that. Look for the entries of the form (lambda +/- inte...

ungefär 9 timmar ago | 0

I can't understand the following MATLAB code documentation
The implication is that the second part is stored in its own file.

ungefär 10 timmar ago | 1

Count from 1 to 0 with increment of 0.01
You need to use a negative increment to count down from a higher value to a lower value.

ungefär 21 timmar ago | 0

Equivalent python for a matlab line?
X = Y[z[i, 0:11],0] would be my guess. However, this relies upon the values in z having been changed to index 0 based instead ...

ungefär 21 timmar ago | 0

What is the difference between [v' 1] and [v', 1]?
v = ((1:3) -(2:4)*1i).' [v' 1] [v', 1] You can see that even for complex numbers, [v' 1] and [v', 1] produce the same results...

ungefär 21 timmar ago | 0

How can I sum each 3 columns array?
reshape(x, size(x,1), 3, []) now you can sum along the second dimension, and then reshape to remove the now-singular second di...

ungefär 21 timmar ago | 1

MATLAB Compiler for a .mlapp that have a .m file
https://www.mathworks.com/help/compiler/unsupported-functions.html Functions Not Supported for Compilation by MATLAB ...

ungefär 22 timmar ago | 0

Increase number of parallel pools coworker by adding hardware?
Check your Parallel Preferences https://www.mathworks.com/help/parallel-computing/run-code-on-parallel-pools.html And check t...

ungefär 22 timmar ago | 0

Datetime doesn't work in uitable
Your reference to handles.file_table tells us that you are using GUIDE and "traditional figures". And in traditional figures, ui...

en dag ago | 0

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How can I split time series in a half?
ts1 = timeseries(rand(1,4096)); %official approach. uses indices ss2a = getsampleusingtime(ts1, 1, 2048); ss2b = getsampl...

en dag ago | 0

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Symbolic integration of Marcumq.
Using the online tool here, execution can get through the calculation of "outer", but the integrals might take a while. Could y...

2 dagar ago | 0

give me invalid use of operator at U, why?
U = 0.75*exp(-((xmid-0.5)/0.1). 2)'; my guess is that you wanted U = 0.75*exp(-((xmid-0.5)/0.1).^2)';

2 dagar ago | 0

What should go in a next-generation MATLAB X?
The ability to assign a subset of fields to a struct (array) would be useful. It is common to want to be change a few settings, ...

3 dagar ago | 0

Finding global maxima and minima
Use calculas. The minima and maxima of a function can only occur at: Critical points of the function; or The boundaries that ...

3 dagar ago | 0

Error in array bounds
"P is 3x2396" No it is not. You assign [] to P.

3 dagar ago | 0

stacking or appending tables with NaN and 'ABC' -- cell vs non-cell
If I understand correctly, you are looping reading multiple files, and want to put the results all into one large table. And tha...

3 dagar ago | 0

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ODE15s Errors defining variable and ODE functions
Your equations involve components which subtract out T0 and P0. When you initialize the boundaries to T0 and P0 that results in ...

3 dagar ago | 0

Polynomial has more than one symbolic variable error
syms m1 m2 J1 s b k1 k2 k3 r1 xi T real t=0:0.5:100; A=[-s^2*m1-s*b-k2, k2, 0; -k2, s^2*m2+k3+k2, -k3; -s^2*J1/r1-s*b/r1, 0, 0...

3 dagar ago | 0

Asking a user in the command window to enter YYYY-MM-DD HH-MM-SS-MS
T = input('Enter time in the form YYYY-MM-DD HH-MM-SS-MS: ', 's') This will give back a character vector that has not been vali...

3 dagar ago | 0

Matlab system and ! commands point to wrong python version?
This is expected. Using ! or system() find the python that is first in your system path, which might not be the same one you hav...

3 dagar ago | 1

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Index timetable variables and remove rows based on criteria.
TT(any(TT{:,2:2001} >= 8,2), :) = [];

3 dagar ago | 0

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Random matrices with constraint
t = rand(n, n); nt = t./sum(t,1); output = nt.*rand(1,n); nt is normalized so that the sum of each column is 1. The s...

4 dagar ago | 1

Extract data from timetable for specific months
[~, mon, ~] = ymd(TT.t1); mask = ismember(mon, [1 2 12]); TTsubset = TT(mask,:); Or if you were looking for specific months...

4 dagar ago | 0

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My code will not run after adding in the code after function dydt=myFunc(t,y)
function dydt=myFunc(t,y) t will be a double precision number representing the current "time". t will seldom be an integer duri...

4 dagar ago | 0

Help For Running MVC2
I suspect you might have started running the program by double-clicking on the .fig file. You need to execute the .m file instea...

4 dagar ago | 1

readtable : set up the multiple lines of variables