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Walter Roberson


Last seen: Today
49,233 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
complex value of syms function for optimization
syms a b c d ; b=c+j*d; Okay, b is a symbolic number that might or might not be complex. "might not be" because d could be 0, ...

10 hours ago | 0

Answered
Converting a whole number to base 2 (Binary Operation)
Consider 19 as an example. 19 is odd, which is to say that the remainder when divided by 2 is 1. Write down the 1, subtract it ...

10 hours ago | 0

Answered
Combination of numbers, lock
compose("%03d",0:999)

11 hours ago | 0

Answered
importing the excel data into matlab in symbolic math tool
Your X is a vector with four elements. When you use it in the equations you are creating a system of four simultaneous equations...

11 hours ago | 0

Answered
Creating Random Sparse Matrices Using For Loop
N = 100; S = 100; RM = cell(N,1); B = zeros(1,N); for K = 1 : N RM{K} = sprand(S, S, 0.01); B(K) = bandwidth(RM{K})...

14 hours ago | 0

Answered
Task,solving in the fastest way
how to get a solution the fastest Commercial quantum computers are available from DWave and IBM. HP expects to release its vers...

15 hours ago | 1

Answered
Simplifying solution of a differential equation
m = rand(); k = rand(); syms y(t) Dy = diff(y,t); Dy2 = diff(y,t,2); ode = m*Dy2 + k*y == 0; cond = [y(0) == 1,Dy(0) ==...

19 hours ago | 0

| accepted

Answered
Image texture on face vertice 3D Model
If you have empty faces, then nothing can be drawn there. Perhaps you should use boundary() https://www.mathworks.com/help/matl...

20 hours ago | 0

Answered
Can anyone suggest how to change the display allignment in command prompt for seeing list of equations
syms x eq(1,1) = expand((x-1)^2); eq(2,1) = expand((x-1)^10); eq char(eq) arrayfun(@disp, eq)

20 hours ago | 0

Answered
there is error in x1(t)
syms t t0 u(t)=piecewise(t<t0, 0, t>=t0, 1); x1(t)=2*u(t-1)-2*u(t-3); T = 0:1/50:10; X1 = double(subs(x1(T),t0,0)); plot(...

21 hours ago | 0

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Answered
Changing value when first time a value appears
A=[1; 1; 1; 1; 2; 2; 4; 4; 4; 4] B=[4; 2; 7; 9; 5; 0; 2; 6; 1; 0] [~, ia] = unique(A, 'stable') B(ia) = nan

21 hours ago | 1

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Answered
Function 'daysact' not supported for code generation.
Correct. That function cannot be compiled. The work-around is to use datetime and subtract. dt1 = datetime('7-sep-2002','Loca...

1 day ago | 0

Answered
How could I use display function for this?
If you mean the derivative as in then MATLAB does not have any direct way to display that in any kind of nice format. All it h...

1 day ago | 0

Answered
Newton Raphson. How to solve it?
If you are using the symbolic toolbox, then MATLAB has jacobian() Otherwise, you need to estimate the jacobian, which you can d...

1 day ago | 0

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Answered
Can I delete the file mw_4a_config.bin from the licenses folder?
The implication of https://www.mathworks.com/matlabcentral/answers/367213-why-do-i-get-the-error-something-unexpected-occurred-a...

1 day ago | 0

Answered
Changing values in a table
No loop should be needed. X = M{:,cl1-1}; M{X == 1, cl1:cl2} = 1;

1 day ago | 0

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Answered
How to Use "Ask a Question" Section Correctly?
Use shift-reload to load the page back in, which will update the cached version of the style sheets. You should only have to do...

1 day ago | 2

Answered
How to apply a matrix to a function?
No, there is no way to do that. When you create a symbolic function by assignment to a variable indexed with a list of symbols,...

1 day ago | 0

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Answered
How to print full size figure using print command?
print() uses the figure PaperSize and PaperPosition properties to decide what size to output.

1 day ago | 0

Answered
error: 'Inputs must be floats, namely single or double' while trying to solve an ODE having an unknown coefficient.
The function you call for ode*() is permitted to use symbolic expressions internally, but the return value must be completely nu...

1 day ago | 1

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Answered
simple Equation, writing formula
Average is sum divided by two. You do not divide by two.

1 day ago | 0

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Answered
store the for result to txt file using dlmwrite
you need the -append flag to dlmwrite and you need to write in full rows, not one element at a time.

1 day ago | 0

Answered
Using a Loop to read and store information?
http://matlab.wikia.com/wiki/FAQ#How_can_I_process_a_sequence_of_files.3F Or potentially you could use a datastore()

1 day ago | 0

Answered
Function inside function using lsqcurvefit
clear all;clc; Okay, so this is a script, not a function. x=[ ]; Ln1=x(1);Ln2=x(2); % necks length S1=x...

1 day ago | 0

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Answered
How to assign voltage levels to bit-groups?
https://www.mathworks.com/matlabcentral/answers/714408-how-to-make-a-4-bits-quantizer-with-15-levels#comment_1258188

1 day ago | 0

Answered
Why are these MATLAB Functions Called?
num2str() and int2str() should be replaced with sprintf() unless you need the behavior of automatically formatting arrays. I ...

2 days ago | 0

Answered
plot field form a orderd vector
lat=[10,11,10,12,13,10] lon=[50,51,52,54,52,51] height=[10,50,120] wind_speed=[7,4,3,2,1,6 ; 8,6,5,4,5,9; 10,8,8,7,6,11] win...

3 days ago | 0

Answered
I tried to convert odes to ss but i have problem//odeToVectorField
Your code had some problems. You were not declaring v as a function. Your definition of eqn3 involved multiplying eqn2 by a v...

3 days ago | 1

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Answered
eulergamma throwing an 'Undefined function or variable' error
[Moving down from comment] You have the Maple symbolic toolbox interface to matlab installed. You need to uninstall that interf...

3 days ago | 0

Answered
ignore NaN values in loop
if isempty(A) CC(:,i) = nan; else A = interpft(A, 100); CC(:,i) = A; end Can interpft operate with only one no...

3 days ago | 0

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