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Walter Roberson


44.580 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
Which Dct Algorithm is used ?
https://www.mathworks.com/help/images/ref/dct2.html#d117e44015 describes the Discrete Cosine Transfer dct2 does dct(), transpo...

circa 8 ore ago | 0

Answered
Vectors must be the same lengths. how to solve this error
STATISTICS(r+1).AVG=avg; r is not changing inside that loop, so you are always overwriting the same location, and all of th...

circa 8 ore ago | 0

Answered
Conversion to double from function_handle is not possible
errors = zeros (n); That says that errors is to be created as an n by n array of double precision values initialized to all zer...

circa 8 ore ago | 0

Answered
What's the transpose complexity Big O in Matlab?
%what's the Big O complexity here for transposing the "a" 1D array. O(1) -- that is, constant in the size of the array. %what'...

circa 8 ore ago | 0

| accepted

Answered
How can I manage a .csv imported file?
mask = YourSignal(:).' > 0; starts = strfind([false mask], [0 1]); stops = strfind([mask false], [1 0]); Now starts and stops...

circa 9 ore ago | 0

Answered
Using dir to extract the names of plexon files for upload
cd(currD) dinfo=dir('day1') Don't do that. Instead dinfo = dir(fullfile, currD, 'day1'); dinfo(ismember({dinfo.n...

circa 9 ore ago | 0

Answered
Change the number of bins in Radon transform
% Grandfathered syntax % R = RADON(I,THETA,N) returns a Radon transform with the % projection computed at N points. R has ...

circa 10 ore ago | 0

| accepted

Answered
Computing the explicit expression of the integral of a function of two variables inetgrated with respective to only one variable
f = vpa([Tau1;Tau2;Tau3;Tau4;Tau5;Tau6],3) You are using finite precision software floating point numbers. TL1 = (1/2)*int(rho...

circa 15 ore ago | 0

Answered
For loops: initialize the sum variable
SUM = SUM + an = (-1/3)^n/(2*n + 1); That is invalid syntax. You cannot have two = in the same statement. end disp(' ') That...

circa 15 ore ago | 0

Answered
Symbolic vector problem in MATLAB
syms(sym('a', [1 4]))

circa 21 ore ago | 0

Answered
non linear equation using newtons method
xold is not defined in your function before the first time you use it. However, your use of xo = [x1 x2 ]'; hints that xold is...

1 giorno ago | 0

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Answered
write a function to calculate f(n)=f(1-1)+f(1-2) where f1=(1),f2=(2)
f(1-1) is f(0) and f(1-2) is f(-1) . The sum of the two would be constant, so f(n) would have to be constant. That is inconsiste...

1 giorno ago | 0

Answered
Generate normally distributed sample from data
You can only do that under the circumstance that the column already contains normally distributed samples. If that is the case t...

1 giorno ago | 0

Answered
How to convert dicom image world coordinates into Cartesian coordinates
See https://www.mathworks.com/matlabcentral/answers/215612-how-can-i-convert-pixels-to-mm-for-a-specific-dicom-image#answer_178...

1 giorno ago | 0

Answered
Loop problem...please help
Take a copy of the input. Go through it starting from the end. If the current entry is the same as the entry before it in the ar...

1 giorno ago | 0

| accepted

Answered
Empty 0-by-1 when using solve:
The equations are inconsistent. If you solve the first 7 equations for [x1, x2, x3, x4, x5, x7, x8], and substitute those in to ...

2 giorni ago | 0

Answered
Call function multiple times but execute once
https://www.mathworks.com/help/matlab/ref/memoize.html

2 giorni ago | 1

| accepted

Answered
plot loop in a legend
plot(Temperatura(:,Dmod(n)),Quota,'-', 'DisplayName', ID{nvar}) hold on plot(Tmis(:,Dmis(n...

2 giorni ago | 1

| accepted

Answered
Multiple function handle in varfun
You can use @(v) [mean(v), std(v)] as the function, and splitvars() afterwards.

2 giorni ago | 0

Answered
How do I use the pcode to regenerate?
You would need the source code r2t.m You appear to be using https://www.rmr.tu-darmstadt.de/lehre_rmr/elearning_rmr/rt2_mat...

2 giorni ago | 0

Answered
How to turn a camera webcam into a video.
camera = VideoReader('slow.avi') nnet = alexnet; % Load the neural net pic = image([]); while hasFrame(camera) pict...

2 giorni ago | 1

| accepted

Answered
How to create a circle within a matrix
x=-.10:.002:.10; %note change from 0.02 to 0.002 [X,Y]=meshgrid(x); % xy space v1=zeros(size(X)); % previo...

2 giorni ago | 1

| accepted

Answered
how save results?
save() permits using a wildcard, such as save('filename.mat', 'z_room*') save() also permits a -regexp option for more complic...

3 giorni ago | 0

| accepted

Answered
Function: Compare each Element of 2 Matrix for zero and non-zero
Z2 = Z^2; output = all(all(~Z2 | Z));

3 giorni ago | 0

Answered
bin_data=imbinarize(r_data);
You need to have the Image Processing Toolbox installed and licensed. Note: imbinarize was new in R2016a, but you do have a ver...

3 giorni ago | 0

Answered
Using a network license on personal computer
Network licenses can be configured to permit "borrowing". See https://www.mathworks.com/help/install/license/borrow-licenses.htm...

3 giorni ago | 0

Answered
How to get cluster more than 2 if i have :
Cluster1 = Y1 > Y2 & Y1 > Y3 & Y2 > Y3 Cluster2 = Y1 > Y2 & Y1 > Y3 & Y2 <= Y3 Cluster3 = Y1 > Y2 & Y1 <= Y3 %Y2 < Y...

3 giorni ago | 0

Answered
Extra commas when using fprintf
Replace fprintf("%.4f," ,M(:,:,i)); With Temp = M(:, :, i) ; fprintf("%.4f," ,Temp(1:end-1) ); fprintf("%.4f...

3 giorni ago | 0

Answered
Error Movie contains unitialized frames
Zach(i,size(r,2)) = getframe; You are creating a 2d array of frames in which you assign into the last column. The other col...

3 giorni ago | 0

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