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Walter Roberson


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48,200 total contributions 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.

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Answered
converting 16 bit image to 12 bit
Different programs deal with storing lower number of bits (such as 12) in higher number of bits (such as 16) in different ways. ...

7 hours ago | 0

Answered
Extract data from a csv file in Matlab
formatIn ='yyyymmdd:HHMM'; It is questionable as to whether that is the correct format, however. Each of the entries ends in 11...

7 hours ago | 0

Answered
Matrix index is out of range for deletion
You have a loop in which you move forward through the loop, deleting entries if some condition matches. However, every time you...

7 hours ago | 0

Answered
Invalid text charcter .Check for unsupported symbol, invisible charcter ,or pasting of non-ASCII chatcters
Your line 7 starts with 11 occurances of char(160), which is unicode U+A0 http://www.fileformat.info/info/unicode/char/a0/index....

7 hours ago | 0

Answered
cpu time in matlab
See timeit() Note though that timeit() deals with elapsed time rather than cpu time -- but it takes a number of steps to try to...

8 hours ago | 0

Answered
URGENT - CAN YOU HELP??
You appear to be using the third party toolbox http://psychtoolbox.org/docs/RestrictKeysForKbCheck . The code you show here doe...

8 hours ago | 0

Answered
How to do partial function on input equations?
var = str2sym(inputdlg(varprompt));

8 hours ago | 0

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Answered
Why CSV date column is imported as NaN ?
dataset = readtable('time_series_covid19_confirmed_global.csv','readvariablenames',true,'preservevariablename',true);

8 hours ago | 0

Answered
How to display two or more values in one fprintf line?
The trick to sprintf() and fprintf() is that each value in memory advances to the next format element. So if you have r = 1:2; ...

8 hours ago | 0

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Answered
How can I save multiple variables simultaneously
If you are saving variables into traditional .mat files (-v7 and before), then MATLAB first collects the list of names of variab...

8 hours ago | 0

Answered
Check for optional inputs in a function using exist
I suspect that it is faster to check nargin. Note: starting R2019b, it is possible to use an "arguments" block to do automatic ...

9 hours ago | 0

Answered
Can you put matab code in an app for users to edit?
Yes, provided that the app is not being compiled (so the users need a matlab license to execute it.) For all of the possibili...

14 hours ago | 0

Answered
I can't graph multivariable function that contains cos function doens't work
Z=exp(X).*cos(Y); Remember that the * operator is matrix multiplication (inner product). Multiplication of corresponding ele...

14 hours ago | 0

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Answered
Input arguments to function include colon operator. To input the colon character, use ':' instead
x1k = @(u1k,x1k) exocstrstateFcnCT1(x1k,u1k); That is a function handle y1 = x1k; That copies the function han...

21 hours ago | 0

Answered
Using eval function for execute a power flow with DC system embedded
Don't *do* that! casefile = sprintf('case_ieee30_test%d.mat', i); savecase(casefile, baseMVA, bus, gen, branch); And...

22 hours ago | 0

Answered
help me to matlab script
sympref('heavisideatorigin', 1) x = @(t) heaviside(t)

1 day ago | 0

Answered
FEVAL Error in Implementing Bisection - Function to evaluate must be represented as a string scalar, character vector, or function_handle object.
that code expects you to pass a function handle as the first parameter.

1 day ago | 0

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Answered
do you have a rate for retirees?
For personal interest there is the Home license. Unfortunately that does not allow access to some of the toolboxes, and is limit...

1 day ago | 0

Answered
What does Sel do in this code?
http://matrix.etseq.urv.es/manuals/matlab/toolbox/mutools/sel.html Very old MATLAB! It looks to me as if is just doing ind...

1 day ago | 1

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Answered
How to select between two identically named built-in functions?
When Mathworks constructs function names it ensures that if there is the same function name, that all except possibly one of the...

1 day ago | 0

Answered
how to save jpeg after compression code ?
save it any way you like, such as using save() into a .mat file, or write the information into different sheet names of xlsx fil...

1 day ago | 1

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Answered
how to generate and precise double value?
randi([0 10], size(x))./10

1 day ago | 0

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Answered
Log Parsing using MATLAB
S = fileread('data_file.txt'); line_matches = regexp(S< '^.*\sharber4797\s.*$', 'lineanchors', 'dotexceptnewline')

1 day ago | 0

Answered
How to get value of X based on a specific value of Y in Graph
x100 = interp1(y, x, 100, 'linear', 'extrap')

1 day ago | 1

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Answered
Bisection Method Error - Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.
rtns=makereturns(20,2); 20 x 2 Q = cov(rtns) 2 x 2 a = [0;1]; B = [1;-1]; 2 x 1 each V = a.*Q*a + 2*a.*Q*B*x + B.*Q*B*x^2 ...

1 day ago | 0

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Answered
Unrecognized function or variable 'phload.'
You are passing phload into toploadph, but toploadph is not passing it into FE which needs it. We can also predict that FE is n...

1 day ago | 0

Answered
convert a function into optimization expressions
The solvers are not compatible with symbolic work. The problem-based approach does not permit you to inject your own functions....

1 day ago | 0

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Answered
Function with Non Constant Variable
syms x output = S(3, 1, x, 2); disp(output) output = S(3, 1, 4, 2); disp(output) function SF = S(F, a, x, n) if isa(a, '...

1 day ago | 0

Answered
Function with Non Constant Variable
syms x output = S(3, 1, x, 2); disp(output) output = S(3, 1, 4, 2); disp(output) function SF = S(F, a, x, n) if isa(a, '...

1 day ago | 0

Answered
Error in entropy function
The entropy function only permits a single parameter. You are probably thinking of the wentropy function, which does permit 'sh...

1 day ago | 0

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