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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 T0099119; if you are waiting on a reply from me for an older issue, please send me a reminder.

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

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Answered
Symbolic summation of vectors/matrices
In MATLAB, it is tempting to use symsum(), but unfortunately that will not work. The difficulty is that the variable of summatio...

41 minutos ago | 0

Answered
how to convert an image into bits???
reshape() to reconstruct the image. The remote side will need to know the image size, so either the size will need to be fixed o...

alrededor de 4 horas ago | 0

Answered
I dont understand, i try to use solve to find x in Matlab Function Block
@Benjamin has shown you how to solve the equation using syms However, syms requires the MATLAB Interpreter, and so is only ava...

alrededor de 15 horas ago | 0

| accepted

Answered
Symbols to numeric values
I already showed you X = double(sol.X) Y = double(sol.Y) Z = double(sol.Z) ... about 11 hours ago. To get that format of di...

alrededor de 15 horas ago | 1

Answered
Unique workspace for each instance of Interpreted MATLAB Function block?
https://www.mathworks.com/help/simulink/ug/model-global-data-using-data-stores.html "In this example, the top model uses a sig...

alrededor de 19 horas ago | 0

Answered
Is it possible to process the sparse matrix faster with vectorization instead of for loop?
Point_Data = readmatrixread('E:\pointdata.txt'); % Point Data = xyz coordinate data of 3D points r = 4; mdl = KDTreeSearcher...

alrededor de 20 horas ago | 0

Answered
What can I use instead of 'lsqcurvefit'
lsqcurvefit()'s normal output is "local minima possible". The only time you do not get that message is if the fitting is being...

1 día ago | 0

Answered
How do I write a .LAS file from .mat data?
guid1 = uint32(0); %32 bit guid2 = uint16(0); %16 bit guid3 = uint16(0); %16 bit guid3 = blanks(8); %unsigned char 8 b...

1 día ago | 0

Answered
How to run the same code over and over with one different detail of an event changing each time (temperature the cooling water turns on).
You already have [t1,y1,te,ye,ie] = ode15s(@(t,y)fun(t,y(1),y(2),y(3),y(4),y(5),y(6),iflag), tspan, initial_conditions,options)...

1 día ago | 0

Answered
Definite integration using int command
h = 5; a = 2; syms y x = 3.8; p = 2.*x.^2+2.*a.*y; q = x.^2+y.^2; r = x.^2+a.^2; f = (-1./sqrt(1-(p.^2./(4.*q.*r)))).*...

1 día ago | 0

Answered
system command in parfor loop
parpool tic parfor i=1:nfiles cmd = sprintf('echo "%s" | multi.exe', str3{i,1}); [status,cmdout] = system(cmd, '-ech...

1 día ago | 0

Answered
Laplace transform not getting Value
syms x(t) Xs eqn = diff(x,t,2)+2*diff(x,t)+26*x(t) == 10*cos(t)*(heaviside(t-pi)); eqnLT = laplace(eqn) eqnLT = subs(eqnLT,l...

2 días ago | 0

Answered
Error: Unrecognized function or variable 'getMatchedFilter'.
The input to getMatchedFilter must be a phased-encoded waveform object, but instead you are just passing in double precision arr...

2 días ago | 0

Answered
Appending multiple Excel files using script
input_dir = '/MATLAB Drive/Project11/xin'; %directory excel files are stored in input_extension = '.xlsx'; %or .xls output_...

2 días ago | 1

| accepted

Answered
Error: Insufficient number of outputs from right hand side of equal sign to satisfy assignment in ft_read_mri
ftver = tmp.Version; Somehowm, tmp is an empty struct or object (that does have a field or property named Version) . Rememb...

2 días ago | 0

Answered
Why the audioread function is giving data samples in two coloum?
That indicates that the audio has two channels (stereo)

2 días ago | 0

| accepted

Answered
How to make the question reappear if someone mess up with the number ? eg. 0 to 4. And then someone type 5.
while true ques_1 = input('\nIn the last month, how often have you been upset because of something that happened unexpected...

3 días ago | 0

| accepted

Answered
how to do pcolor plots from 3d data?
x=100; y=100; z=100; r = randi([1 5],x,y,z); cmap = [0 0 0; 1 0 0]; mask = double(r(:,:,60) == 1); imagesc(mask, 'AlphaDat...

3 días ago | 0

| accepted

Answered
how to discretize the 3-D surface into individual points in MATLAB
F = @(X, Y) sin(X).^2 - cos(3*Y).^2; %equation of the surface xvec = -1:0.1:1; yvec = -3.2:.1:3.2; [x, y] = meshgrid(xvec...

3 días ago | 0

Answered
imread, reshape and zeros function syntax problems
imread() returns the data type stored in the file. The most common data type stored in image files is uint8(), but there are oth...

3 días ago | 0

| accepted

Answered
circshift function working explanation needed
M = (10:10:40).' + (1:9) circshift(M, -1) You can see that this is the same as [M(2:end,:); M(1,:)] And more generally, circ...

3 días ago | 0

Answered
How to save image after encryption?
My suspicion would be that your original image is uint8 and that when you did the encryption, you did not make sure to create ui...

3 días ago | 0

Answered
Solving Equaiton with multplying power
syms A B C syms X Y Z integer eqn = (B*C^-1)^X * (B)^Y * (A*B^-3)^Z * (B^3*C^-1) == A^0*B^0*C^0 seqn = simplify(lhs(eqn)) == ...

3 días ago | 1

| accepted

Answered
Workspace Updates when script is complete?
Correct. Generally speaking, there would be too much overhead to continually update the workspace browser when you are not stop...

3 días ago | 0

| accepted

Answered
Overlay gray ROI on an image
newI(row1 : row2, col1 : col2) = repmat(GrayRoi, [1 1 size(newI,3)]);

3 días ago | 0

| accepted

Answered
read/write csv file
dlmwrite() offers the option -append . Note, however, that this is restricted to writing additional rows immediately after all ...

3 días ago | 0

| accepted

Answered
call a variable in a timetable from a cell matrix
for 1 = 1:10 a(:,i) = Timetable.(VariableNamesMatrix{i}); end But you should consider just using a = table2array(Timetab...

4 días ago | 0

| accepted

Answered
python to Matlab udp communication
https://www.mathworks.com/matlabcentral/answers/319729-how-can-i-receive-udp-broadcast-data-in-matlab-using-instrument-control-t...

4 días ago | 0

Answered
Issue with native2unicode and windows-1252 encoding
source = char(0:511) bytes = unicode2native(source, 'windows-1252') backport = char(bytes) whichdiffer = find(source(1:256) ~...

4 días ago | 0

Answered
Write a cell array to a .csv file
These days, use writecell()

5 días ago | 0

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