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Walter Roberson


Last seen: Today
50 842 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
File format not accepted
https://www.mathworks.com/matlabcentral/answers/316872-how-to-read-a-gps-rinex-observation-and-navigation-files-in-matlab-direct...

environ 2 heures ago | 0

Answered
How to map Boolean functions
tab1 = [0 0 0 0;0 0 0 1;0 0 1 0;0 0 1 1 ; 0 1 0 0;0 1 0 1;0 1 1 0;0 1 1 1;1 0 0 0;1 0 0 1;1 0 1 0;1 0 1 1;1 1 0 0;1 1 0 1;1 1 1...

environ 8 heures ago | 0

| accepted

Answered
Can Matlab's arguments function handle structs
It does not appear to be possible. One work-around would be temp = [string(fieldnames(Struct)), struct2cell(Struct)].'; foo(t...

environ 9 heures ago | 0

Answered
Maximum value and its position
[maxvalue, maxidx] = max(Data(:,2)) time_of_max = Data(maxidx,1)

1 jour ago | 0

| accepted

Answered
edit large CSV file before reading it to a table
https://www.mathworks.com/help/matlab/ref/matlab.io.text.delimitedtextimportoptions.html Use 'delimiter', ';', and 'SelectedVa...

1 jour ago | 2

| accepted

Answered
Need help with Turbo product code
img = de2bi(img); That is something by 8, where the something is the number of elements in the original image. resized = imres...

1 jour ago | 1

Answered
Why the evalfis output is ignored (not displayed, no error message)
output_fis3 = evalfis(aggTree,[50 100 34 2500 1800]); ^ ...

1 jour ago | 0

Answered
function in matlap#
f = @(x) x * appropriate_multiplier_goes_here - transaction_cost(x) where transaction_cost is a function that calculates the tr...

1 jour ago | 0

Answered
Getting values out of cell arrays
output = cellfun(@(C) C(20:50,:), YourCellArray, 'uniform', 0);

1 jour ago | 0

| accepted

Answered
How to read zipped fies without open them
See https://www.mathworks.com/matlabcentral/answers/111836-how-to-unzip-files-using-external-unzip-software#answer_120392 and ...

1 jour ago | 0

Answered
MATLAB: Index exceeds the number of array elements (1)
x1=(1 -0.3); That is not a vector: it is 1 minus 0.3 . x1=[1, -0.3];

1 jour ago | 0

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Answered
convert knnclassify to fitcknn
x = readtable("https://www.mathworks.com/matlabcentral/answers/uploaded_files/600525/datatraining.xlsx"); y = readtable("https:...

1 jour ago | 0

| accepted

Answered
how can i avoid Nan in matlab expression and return 0
The following is not exactly right: M = optimvar('M', 1, 5) costa = 5 costb = 10 delta = eps(realmin) part1a = (M - sqrt(M....

1 jour ago | 0

Answered
How can I plot a line on a plane?
C = randi([-9 9], 1, 9); a = C(1), b = C(2), c = C(3), d = C(4), e = C(5), f = C(6), p1 = C(7), p2 = C(8), p3 = C(9) syms x y ...

1 jour ago | 1

| accepted

Answered
I could not integrate using MatLab, Can you please help me?
syms a c t real mag_dr = 3*2^(1/2)*(1 - cos(4*t))^(1/2)*(a^2 + c^2)^(1/2) z = int(mag_dr, t) z - limit(z, t, 0, 'right') The...

2 jours ago | 1

Answered
Undefined function 'string' for input arguments of type 'cell'.
string() needs R2016b or later, but you are using a release before that. For this specific purpose you can define string = @(x...

2 jours ago | 0

Answered
Resizing a binary image issue
This is to be expected. You are compressing by a factor of 70 for rows and 63 for columns, so each output pixel is calculated b...

2 jours ago | 0

Answered
Is there any maximum for the size of matlab table?
table() objects are restricted to: no more than 2^48 - 1 = 281474976710655 variables each variable is restricted to no more th...

2 jours ago | 1

Answered
How do I get 3 comets to launch at once?
You cannot do that with comet() . Each call to comet() does not return until the display is finished. You will need to use a di...

2 jours ago | 0

Answered
how to change the markers and line style, for 'findpeaks' ?
ax = gca; sig_h = find(ax, 'tag', 'Signal'); peak_h = find(ax, 'tag', 'Peak'); As you are asking to plot Extents as well, you...

2 jours ago | 0

| accepted

Answered
Assigning multiple variables a single legend
%% NREM hold on; h1=bar(categorical({'PT5',}),size(PT5_Changed.NREM_Bout_Wise_Firing_Rate,1),0.1,'FaceColor','b'); h2=bar(c...

2 jours ago | 1

Answered
Index exceeds the number of array elements (0).
data = readtable('eplusout.csv', 'readvariablenames', false); Cooling_column = data{290:313,21}; zone_air_temp = data{290:313,...

3 jours ago | 0

| accepted

Answered
How can i fix this error?
size(X)=5000*784 size(Y)=5000*1 size(w)=784*1 OKay, so Y.*X.' would be (5000 x 1) .* (784 x 5000) which would be an error. I...

3 jours ago | 2

| accepted

Answered
find the position of all non-zero minimum values in each column of a matrix
a = [2 0 3;1 2 5;0 0 0;1 3 3;0 0 6;0 2 7;1 0 0] positions = cellfun(@(A) find(A==min(A)), num2cell(a,1), 'uniform', 0) The re...

3 jours ago | 0

Answered
Matlab engine: License Checkout Failed
error -39: you or your host are not listed in a group license https://www.mathworks.com/matlabcentral/answers/98895-why-do-i-rec...

3 jours ago | 0

Answered
How to know pixel size ?
data = readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/607160/125-1.csv'); imagesc(data) th = data ...

3 jours ago | 0

Answered
how to sample an audio file ?
[data, fs] = audioread('name_of_file_goes_here.wav'); num_seconds = 1; %does not need to be integer sample_length = floor...

3 jours ago | 0

Answered
Create a simple rectangular image
img(row_white_start:row_white_start+num_white_rows-1, col_white_start:col_white_start+num_white_cols-1) = 1;

3 jours ago | 0

Answered
I want to know how to create a struct type mat file
result = cell2struct({currency.feature}, {currency.name}, 2); The result would be a struct with fields named 'Dollar', 'pound',...

3 jours ago | 1

Answered
How does bitshift work?
dec2bin(56,8) In other words, your difficulty is that 0101 0110 is not the correct representation for 56.

3 jours ago | 1

| accepted

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