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Walter Roberson


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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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Solve two simultaneous equations for a set value of y
y = 1.4; syms x A = (1/x)*(2/(y+1)*(1+(y-1)/2*x^2))^((y+1)/(2*(y-1))); P = (((y+1)/2*x^2)/(1+(y-1)/2*(x^2)))^(y/(y-1))*((1)/(...

31분 전 | 1

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Having scale that changes on same axis
MATLAB does not have any support for changing a scale for only part of an axes. You will need to use a second plot. Some people...

약 1시간 전 | 0

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Jacobi iteration what the wrong of my code please help
size(d) is 4 x 4, so size(inv(d)) is 4 x 4. size(b) is 1 x 4. You cannot use matrix multiplication * operator between a 4 x 4...

약 1시간 전 | 0

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How do I reshape a vector into a zero-diagonal matrix?
x = [1;2;3;4;5;6;7;8;9;10;11;12]; nx = numel(x); n = ceil(sqrt(nx)); if nx ~= n*(n-1) error('vector is wrong size to ma...

약 1시간 전 | 0

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Plotting specific data points from a vector/double
plot(face_orig([1:104, 107:255])); However, this would give you a result as-if the entry at 107 were from 105. You should more ...

약 4시간 전 | 0

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How to draw these signals on matlab
plot(rand(1,10)); ylim([-0.1 1.1]) yticks([.1 .5 .9]) yticklabels({'$$Output$$', '$$\begin{array}{r}non-\\Inverting\\Input\en...

약 5시간 전 | 1

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How to plot Fourier transform of the signal from a text file (*.txt) ?
filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/614995/DATA.txt'; data = readtable(filename, 'readva...

약 6시간 전 | 0

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Light direction in surfl
The bright area is mostly because of the specular lighting that is being introduced. doc specular says R = specular(Nx,Ny,Nz,...

약 6시간 전 | 0

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how to solve "error using griddata" in order to plot an efficiency map
% test arrays have corresponding size speedRPM = 1:200; % 1x200 TorqueNm = 1:100; % 1x100 EffeciencyPer = speedRPM + TorqueNm...

약 7시간 전 | 0

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make our own signum
Under the interpretation that nan values are not less than 0 (they are not greater than 0 either) output = (value < 0) .* -2 + ...

약 7시간 전 | 0

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How can I merge 100 .xlsx files into one file?
%the below code does NOT assume that the input is numeric. %the code DOES assume that all files have the same datatype for %co...

약 7시간 전 | 0

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Using XY Data from this example? Help please
After the call to geometryFromEdges(model,g); then model.Geometry.Vertices will give you the initial geometric coordinates a...

약 8시간 전 | 0

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How do I subplot from a large file? Note..any .txt file of any large figures can be given. So please solve generally.
You could calculate N more cleanly as N = size(r, 1); T and c and r will each be a single column. You take the number of row...

약 9시간 전 | 0

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Unable to perform assignment because the size of the left side is 1-by-4680 and the size of the right side is 1-by-9360, how can i solve this error?
According to the documentation, the returned size is https://www.mathworks.com/help/vision/ref/extracthogfeatures.html#btxscw9-f...

약 10시간 전 | 0

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Parentheses error with a function call
[copying down from correct comment] I do not see any problem with the code extract that you posted. Perhaps the error is insid...

약 10시간 전 | 0

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Is it possible to control two Arduino boards in parallel using parfor?
The arduino object data is not being copied to the workers. Use parfevalOnAll to run an initialization on each worker that cre...

1일 전 | 0

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I need to create a 3d plot with each step of fminsearch
options = optimset('MaxFunEvals',3000,'Display','iter','PlotFcns',@plot_12z); and function stop = plot_12z(X,OPTIMVALUES,STATE...

1일 전 | 1

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Parse error at x:usage might be invalid matlab syntax
MATLAB has absolutely no implied multiplication. Not anywhere. Not even slipped down behind the sofa cushions. 3x needs a mult...

1일 전 | 0

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What instruction could give me this result?
You cannot get MATLAB to display in that particular way as a symbolic expression. You can convert to character and display. sym...

1일 전 | 1

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Concatenating columns while reading tables
ngroup = (size(t,2)-1)/3; newt = [t(:,1),cell2table(mat2cell(t{:,2:end}, ones(1,size(t,1)), 3 * ones(1,ngroup)))]; newt.Proper...

1일 전 | 0

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Problem is unbounded with linprog
Consider an objective of 2*x - y with constraint x-y <= 4 . Let x = y = 10^N . Then with x and y being the same, x-y is 0 which ...

1일 전 | 1

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unable to exit matlab program
When you quit() or exit() then finish is automatically run https://www.mathworks.com/help/matlab/ref/quit.html and https://www.m...

1일 전 | 0

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답변 있음
How to vectorize the following code?
f(g(1:2,:)) = g([3 3], :);

1일 전 | 1

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답변 있음
for loop for matrix
A = randi([-9 9], 10, 10) A = {A}; for K = 1 : 3 A{K+1} = A{K}*A{1}; figure(); surf(A{K+1}); title("iteration " + K) ...

1일 전 | 0

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i get error can any one help
f= @(x,y,z) [((x-4)^2 - z) ;( 2*y-4*z); z+16*(x-8)+1/y -21] Inside [] if you have an expression of the form A -B then that does...

1일 전 | 0

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What is the best way to organize two header lines in a Table?
If you must use readtable() then you are going to need two calls, one to read the first header line. Alternately you could use ...

1일 전 | 0

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assign characters in a for loop combined with switch case and then merge to a long string
strjoin() defaults to putting space between the parts. Use a second parameter of '' to not put in spaces.

1일 전 | 1

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Why does not semilogy works?
loglog() and semilogy() and semilogx() have no effect if "hold on" is already in effect for the axes. You cannot mix log coordin...

1일 전 | 0

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Integrate a ODE with anonymous functions
The message implies that your state0 is a vector of length 13, but your 'AbsTol',1e-9*ones(1,12) is only creating a vector of le...

1일 전 | 1

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Conversion of Gregorian date to decimal years
basetime = datetime('1992-01-01 00:00'); gtime = 23853938 t1 = basetime + seconds(gtime) t2 = dateshift(t1, 'sta...

2일 전 | 0

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