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Walter Roberson


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50.636 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
How to change values for variables that are defined in a equation
syms a b c d syms x eqn = (a - b + 6.96*x + (6-(31*c)/1000)*x/60*1000 + 31*c/1000*d/60*1000)*0.0081 - 0.1824 -x == 0; sol = s...

alrededor de 1 hora ago | 0

| accepted

Answered
Sharing C mex variables Between Client and parallel Workers
mexMakeMemoryPersistent is the equivalent of persistent and is not the equivalent of global . If you need changes in one worker...

alrededor de 1 hora ago | 0

Answered
Read table in .txt to MATLAB
%Read data file: Drag and Lift Coeff. saveFlCdCl = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/586711/Save_...

alrededor de 1 hora ago | 0

Answered
1000 separator and decimal separator are both commas
str2double(regexprep(s, {',(?=.*,)', ','}, {'', '.'}))

alrededor de 3 horas ago | 0

| accepted

Answered
extract one of the bits in fi(), flip it, and reassemble it to produce new bin
input = '1010'; input(3) = 'a' - input(3) ... It's magic ;-) flipped = (1 - (x - '0')) + '0' flipped = 1 + '0' + '0' - x fl...

alrededor de 3 horas ago | 0

Answered
Split arrays and Apply function
event1 = [7.046, 15.66, 24.16] B = [0.53, 1.25, 2.01, 2.78, 3.51, 4.25, 4.96, 5.78, 6.55, 7.26, 7.98, 8.76, 9.54, 10.32,11.08, ...

alrededor de 3 horas ago | 0

Answered
I am unable to solve my system of equations using MATLAB, Can anyone go through the code and suggest me some?
syms x1 x2 y1 y2 z1 z2 syms d d1 d2 intersxn_angle theta1 theta2 syms x y z eqn1 = (x-x1)*(x-x2)+ (y-y1)*(y-y2)+(z-z1)*(z-z...

alrededor de 4 horas ago | 1

| accepted

Answered
How to plot a sphere using plot tool
You can construct a list of coordinates, X, Y, Z, and use plot3(X, Y, Z, '*') to cause the points to be plotted in 3 space, w...

alrededor de 4 horas ago | 0

Answered
If, ||, && statements
if Matrix(1,:)=='0'||Matrix(2,:)=='0'||Matrix(3,:)=='0'||Matrix(:,1)=='0'||Matrix(:,2)=='0'||Matrix(:,3)=='0'||(Matrix(1,3)=='0'...

alrededor de 5 horas ago | 0

Answered
matlab unable to classify variable in parfor loop
b_t(i,i) = phi_t(2); The parfor loop control variable can only occur in one index location. Store the contents into a vecto...

alrededor de 10 horas ago | 0

Answered
Tic Tac Toe game
if A&&B==0 does not mean if A is 0 and B is 0, it means if A is true if B==0 do body end end MA...

alrededor de 10 horas ago | 0

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Answered
defining the mean of a values inside a matrix
A = randi(9, [1 6]) [A(1), A(1:end-1) + diff(A)/2, A(end)]

alrededor de 14 horas ago | 3

| accepted

Answered
for loop label/arguement
That looks suspiciously like an Octave message rather than a MATLAB message... x(j+1)=mu*x(j)(1-x(j)); ^^ MATLAB...

alrededor de 15 horas ago | 0

Answered
Keep getting the following error : Unable to convert expression containing symbolic variables into double array.
Recheck your assignments and your indexing. b = [0 -2 -1 -1]'; A = [1 0 -1 3; 0 2 1 0; -1 1 6 -1; 3 0 -1 10]; syms alpha rea...

alrededor de 15 horas ago | 0

Answered
While running this program I got the error "Error using mesh (line 71) Data dimensions must agree"
f=1000; s=300; theta= 45; dp=0.000005; rb=35; Rt=20; Rmj=18; Rmn=9; v1=0.4999; v2=0.05; E1=50; E2=137000; t=0:0.1:30...

alrededor de 16 horas ago | 0

Answered
How can I write this for Matlab?
if ismember(phrase(i), '79') result = result + 5; elseif ismember(phrase(i), ['SZ' '2':'6' '8']) result = result + 4; ...

alrededor de 16 horas ago | 0

Answered
speed up a for loop
Inside your inner for loop, you read three .nc files. For efficiency, you need to reduce the number of files you need. So revers...

alrededor de 16 horas ago | 0

| accepted

Answered
How to check entries in a Matrix diagonal by diagonal
[nrow, ncol] = size(A); count_around = @(A,R,C) sum(A(max(1,R-1:R+1):min(nrow,R-1:R+1), max(1,C-1:C+1):min(ncol,C-1:C+1))) - ...

alrededor de 16 horas ago | 0

Answered
How Do I Perform Decoding Morse Code Using GUI?
Hint: strsplit() the morse, and ismember into the list of codes to figure out which is being matched. morse={'.----','..---','...

1 día ago | 0

| accepted

Answered
How to convert from plot3 to surf?
format short g; format compact; fontSize = 18; counter= 0; counter1=0; for ky=0:1:1000 for i=0:1:89 ...

1 día ago | 1

Answered
Accelerometer data to obtain tremor frequency
triax = readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/587501/anj%20off%20rt.txt'); Fs = 333; ns...

1 día ago | 0

Answered
I need to plot the same graphic of the image, but without any loop.
x = -5*pi:pi/100:5*pi; k = (1:1:100).'; %not 0! y = sum(2.*( ( (-(-1).^k)./ k ) .* sin(x.*k) )); plot(x,y)

1 día ago | 0

| accepted

Answered
Attempt to extract field 'Bc' from 'double'_error.
qeT.Bc needs to have the period replaced by an operator such as qeT*Bc

1 día ago | 0

Answered
How can I correct this error?
LD(:,4:5)=LD(:,4:5)/Zbase; and similar on the next line. The assignment to N requires one more close bracket.

1 día ago | 1

| accepted

Answered
MATLAP plotting with a range of values on x axis.
discretize() with categorical labels https://www.mathworks.com/help/matlab/ref/double.discretize.html#d123e329049

1 día ago | 0

Answered
Why do I get a connection error when installing or activating MATLAB or another MathWorks product?
Data point for MacOS Catalina: I have not had difficulty downloading or authenticating to Mathworks until just now. I was insta...

1 día ago | 0

Answered
Vectorization of a function with system of ODE's
function dydz = famp(pa,N0,pe,se,k,y,z) y = reshape(y, [], 2); k=Par.N0*pa/(pa+pe); dy1 = y(:,1).*(pa.*N0+(pa+pe).*(k.*y(:,1...

1 día ago | 0

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Answered
Non numeric data X plot
In this particular case, you can plot something meaningful. In most cases, you cannot plot with unresolved symbolic variables un...

1 día ago | 0

| accepted

Answered
Matrix Dimension Must Agree
clc clear %%deklarasi variabel n = 377; f = 3*(10^9); c = 3*(10^8); lambda = c/f; I = 1; r = 10*lambda; theta =...

1 día ago | 0

Answered
Periodic Number Problem Loosing Decimals
If all of the values involved are rationals then you can use the Symbolic Toolbox.

1 día ago | 1

| accepted

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