Community Profile # Walter Roberson

Last seen: Today Actif depuis 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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Finding a redundant pattern in a matrix
C1=[ 5 9 3]; C2=[ 9 5 3]; C3=[9 5 9 3]; C4=[5 9 8 3]; C5 = [5 3 9 8]; is_in(C1, C2) is_in(C1, C3) is_in(C1, C4) is_in(C1, ...

environ 12 heures il y a | 0

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Connecting to USB device with serialport vs. serial command
serialport does not have any fopen() or fread() . It automatically opens the port when you create the object, and it uses read()...

environ 13 heures il y a | 0

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Empty matrix, scalar, or vector function in loop
MATLAB uses == for comparisons, not = Also, X = [] Y = 1 if X == []; disp('X yes 1'); end if Y == []; disp('Y yes 1'); end ...

environ 13 heures il y a | 0

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Numeric data becomes zero after conversion from Table
I predict that you have format short in effect, and that what is being displayed is not really 0 but is instead something of t...

environ 13 heures il y a | 0

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Why results of the 'solve' are wrong?
p_max=715.685424949238; (and a bunch of other numbers). What does that input mean? Does it mean that p_max is exactly ? Does ...

environ 15 heures il y a | 0

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Excel sheet data upload "Invalid 'DataRange'. The column size must match the number of variables".
opts.DataRange = "A2:AT78"; That requests that column "A" to "AT" be read in. However, M1_New_Macro1.xlsx only has data up to c...

environ 15 heures il y a | 0

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Logical operator not evaluating correctly
A|B is an or test and returns a logical value -1 is nonzero which is considered true, and since you or everything together you a...

environ 17 heures il y a | 0

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Hi.How I can plot W_m to n connection
See <https://www.fieggen.com/shoelace/lacingmethods.htm> for some of the possible ways to plot that.

environ 23 heures il y a | 0

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Receiving mouse clicks in App Designer UIAxes - stops working after imshow
https://www.mathworks.com/help/matlab/creating_plots/capturing-mouse-clicks.html MATLAB considers graphics objects to be layer...

1 jour il y a | 0

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molecular code in matlab
There are a lot of undefined variables there. There are two possibilities: There might be another script that you have to exec...

1 jour il y a | 0

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Need help coding this
Example. fun = @(x, y) (x + y).^3 - 5*(x.*y) - 1; [X, Y] = meshgrid( linspace(0,2)); z = fun(X, Y); contour(X, Y, z);

1 jour il y a | 0

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I have a data 5x148992 , i have to extract data column wise and check if there is any changes wrt previous column and display when there are chnages?
for i = (data( : , : )) data appears to be a 2D array. When you have something of the form for VARIABLE = EXPRESSION; BODY;...

1 jour il y a | 0

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How to add Line/Markers to an Axis Label?
L = "G\prime ( \bullet ) and G\prime\prime ( \color{red}{\bullet}\color{black} ) (Pa)"; ylabel(L, 'interpreter', 'tex') See al...

1 jour il y a | 0

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How to calculate the symbolic integration of rational functions?
Wolfram Alpha says https://www.wolframalpha.com/input?i=int%281%2F%28x%5E4+%2B+x%5E3+%2B+x%5E2+%2B+x+%2B+1%29%2C+x%2C+0%2C+1%29&...

1 jour il y a | 0

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Large square symmetric matrices inversion in parallel / distributed systems
Gb = 60000^2*8/1024^3 The matrix is close to 27 gigabytes. The inverse is the same size, so you will need at least 54 gigabytes...

1 jour il y a | 0

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How to make a new column in my table
elseif requires a expression after it, but you coded an assignment. You just want else not elseif Remember that if Results(...

1 jour il y a | 0

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Need a to plot a graph
hvals = linspace(0,17); numh = length(hvals); Vtotal = zeros(numh, 1); H1 = 11; %in H2 = 5; %in m r1 = 3.5; %in m r2 = ...

1 jour il y a | 0

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only Mathworks Sales can generate trials against older versions.

2 jours il y a | 0

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How to shift elements in matrix?
circshift()

2 jours il y a | 0

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how can i imagie zoom with Convolution method
It is deliberate that the following does not do exactly what you want to do. It is also deliberate that it has some extra steps ...

2 jours il y a | 0

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How can I simplify my code using loops?
Put the channels into a cell array: lena_ch = num2cell(lena, [1 2]); Now you can loop over the rows of indices = perms(1:3) ...

2 jours il y a | 0

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I need help writing equation in matlab
format long g syms x n m result = symsum(x^n/factorial(n), n, 0, m) limit(result, m, inf) result20 = subs(result, m, 20) ex...

2 jours il y a | 0

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How can I make the execution speed consistent while I am testing the speed of the programs?
I am not convinced that virtual machines will be allocated dedicated resources that will not be affected by other activities. ...

3 jours il y a | 0

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Hello, I've got the problem. Can any one help me with that error?
cond = [x(0)==0, diff(x, t)==0]; The first part of that sets a boundary condition. The second part of it says that the deri...

3 jours il y a | 0

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how can I calculate A^n when n is a symbolic positive integer?
syms N positive integer [V, D] = eig(sym(A)) result = V*diag(diag(D).^N)/V Note those are the matrix operations *...

3 jours il y a | 0

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how to run a function on GPU cores
You would have to use <https://www.mathworks.com/help/gpucoder/index.html> Nvidia GPUs are constructed in a hierarchy. GPU co...

3 jours il y a | 1

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Hi, I am trying to produce randomly circles with same radius in defined range or square. I wrote the code, but it show error " Out of memory. The likely cause is an infinite"
function h = circle(x,y,r, N) ... for i=1:1:size(circle) circle is not a local variable in the function circle, and is not th...

3 jours il y a | 0

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Axis Ticks using Calendar Year ticks with BC years
YearTicks = datetime({'1950 CE'; '1725 CE'; '1501 CE'; '1277 CE'; '1053 CE'; '0828 CE'; '0604 CE'; '0380 CE'; '0156 CE'; '0069 C...

3 jours il y a | 0

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Simlify a function in matlab
syms B C x eqn = cos(x) + B*sin(x) == C expr = -sin(x) + B*cos(x) xsol = solve(eqn,x) newexpr = simplify(subs(expr, x, xso...

3 jours il y a | 1

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Call parfeval using global variables?
When you pass a global as a parameter, what is received in the called routine is treated as a local. For example, assigning to t...

3 jours il y a | 2