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Walter Roberson


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47,190 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
Data Acquisition Toolbox with Simulink: Counter Input Channel
turn off rapid acceleration. You can have normal acceleration but you will probably need to mark a number of functions as exte...

1 hour ago | 0

Answered
Can I programmatically do file I/O on AWS EFS or EB3?
https://www.mathworks.com/help/matlab/release-notes.html R2020a copyfile() supports aws s3: URI.

6 hours ago | 0

Answered
Error with Measure Distances in an Image
images.roi.Line needs at least R2018b I believe.

7 hours ago | 0

Answered
How to solve exponential equation ?
The empty answer is correct. When you solve(), you are asking for the set of values for variables that makes all of the equatio...

7 hours ago | 0

Answered
Readtable reads my timestamp data as NaN
filename = 'heart.csv'; S = fileread(filename); datacell = textscan(regexprep(S, ':(\d\d\d)', '.$1'), '%f%T%f%f%f%T%f%T', 'hea...

7 hours ago | 0

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Answered
using interp1 'nearest' and 1 value is missing
nearest= interp1(refDateTime, 1:length(refDateTime),expDateTime, 'nearest', 'extrap') The interpolation mode you were using, li...

8 hours ago | 0

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Answered
cannot save quadrature data
file_name ='data.txt'; fid = fopen(file_name, 'w'); fprintf(fid, '%.17e%+.17ei\r\n', [real(data.'); imag(data.')]); fclose(fi...

8 hours ago | 0

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Answered
Help with solve under the symbolic environment
%Calibration p0 = 0.05; p1 = 0.1; lambda = 0.1; ybar = 1; kappa = 0.9; b0 = 0.5; c1 = 0.4; alpha = (ybar*lambda*(1-p0)/p...

11 hours ago | 0

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Answered
Searching for specific pattern and returning 16 values/data characters from the last index of occurrence of my specific pattern
input1 = [0 0 0 0 0 1 0 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 0 1 0 1 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ]; substring=[0 1 0 1]...

11 hours ago | 0

Answered
About copying txt to matrix
filename = 'whatever.txt'; fid = fopen(filename, 'rt'); data = cell2mat( textscan(fid, '%f%f%*s') ); fclose(fid);

13 hours ago | 0

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Answered
"str2sym" delete the element wise operation
This is correct behaviour for symbolic expressions. The symbolic toolbox assumes that any unresolved symbolic variable name w...

14 hours ago | 1

Answered
animatedline fails after the first iteration
Create the subplot and modify their position before the loop. Make sure to pass the axes to the hold() and grid() calls. At p...

15 hours ago | 1

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Answered
How to associate a rectangle with a struct?
rgb = imread(filename) ; mask = rgb(:, 1) < 32 & rgb(:, 2) > 224 & rgb(:, 3) > 224; mask = bwareafilt(mask, [50 inf]); ...

15 hours ago | 0

Answered
Conversion to double from struct is not possible.
Filenames = dir('*mat'); numfiles1 = length(Filenames); EEGSinDC = cell(numfiles1, 1); for i = 1 : numfiles1 filedata = l...

1 day ago | 0

Answered
Yaxis becomes periodic after using ylim
I predict that you have either used yyaxis or xxaxis, or else that you have use the older plotyy(), or else that you called axes...

1 day ago | 1

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Answered
extract numbers or string after specific symbol from a text file
dinfo = dir('*.txt'); nfiles = length(dinfo); filenames = fullfile({dinfo.folder}, {dinfo.name}); IDs = cell(nfiles,1); FC...

1 day ago | 0

Answered
Imwrite creates 8bit tif file despite 16bit input
https://www.mathworks.com/help/matlab/ref/imwrite.html If A is a grayscale or RGB color image of data type double or single, t...

1 day ago | 0

Answered
About the install and configuration GPU for matlab 2020a
https://www.nvidia.com/Download/index.aspx Use that to download the appropriate driver for your system. You can download the ...

1 day ago | 1

Answered
Expression representation in an Iteration
W_k = cell(N,1); w=[randn(2,1)+ij*randn(2,1)]; W_k{1} = w*ctranspose(w); for n=1:N; w = randn(2,1)+ij*randn(2,1); W...

1 day ago | 0

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Answered
piecewise for use in anonymous functions
Rmaxtb00 = matlabFunction(Rmaxtb0, 'File', 'Rmaxtb00.m', 'optimize', false); The generated function in the .m file will use if/...

1 day ago | 1

Answered
Transfer Function with one 1/s term
You cannot do that with Control System Toolbox tf() function. tf() keeps numeric vectors of coefficients with implied powers; it...

1 day ago | 1

Answered
If expression to check whether a particular function has been called
In the general case, there is no way to detect whether a particular function has been called. If you turn on profiling before y...

1 day ago | 1

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Answered
I'm new to matlab and am trying to sort an array in ascending order without using the sort command. How would I rectify this?
You have for i=1:length(a) so i can be equal to length(a) . Then you do if a(i)>a(i+1) When i has become length(a) t...

1 day ago | 1

Answered
How to edit colors for the line?
We do not know exactly what PlotCone does, but we can predict from the observed behavior that it is creating more than one line(...

1 day ago | 0

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Answered
Graph two curves together (datetime format and double format)
hB=plot(tEnersol.Date,tEnersol.Rad, '.r'); hold on % bar plot against actual date That is the first plot in the axes, and i...

1 day ago | 0

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Answered
fminbnd got stock in local minimum: can global search deal with the problem defined by cases?
fminbnd() cannot handle functions defined by cases. None of the functions in the Optimization toolbox can: they all depend upon ...

1 day ago | 0

Answered
I want to produce square wave without using square function, but this code it showing error, "illegal use of IF keyword". How to rectify it?
In MATLAB, {} is used only for building cell arrays, or extraction of data from collection objects, such as cell arrays or table...

1 day ago | 0

Answered
XMAX must be a floating point scalar
For integral2(), the limits of the second variable can be function handles, but not the limits of the first variable. You need ...

1 day ago | 1

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Answered
How do I read begin to read data after a string?
filename = 'ConcreteStresses.txt'; S = fileread(filename); idx = regexp(S, '^\s*\d', 'once', 'lineanchors'); fmt = repmat...

1 day ago | 0

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Answered
How to convert a matrix to a table with headings
T = array2table(X, 'VariableNames', {'Time', 'WindDirection', 'WindVelocity', 'Temperature', 'Precipitation', 'DewPoint', 'C7', ...

2 days ago | 0

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