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# Walter Roberson

##### Last seen: Today
46 482 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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Find Fundamental Frequency to know if it´s a Man or a woman or children
Your project is not possible to complete using any known science. Suppose for example that group A has a mean score on somethin...

ungefär en timme ago | 0

Why are the results different when calculating a 10 x 3 matrix and a 1 x 3 matrix?
XYZ_rwd21t = [1.30937778204061e-14,-13.8617246105272,22.6275000000000; XYZ_rwt212t(i, 2) = XYZ_rwd21t(1, 2); Okay, so ...

ungefär 3 timmar ago | 0

fminsearch for ligistic fit
f2 = @(p)f(p,x); That relies on x existing in your workspace. If you are going to do that you might as well assume it on the...

ungefär 13 timmar ago | 0

Adding elements of a vector in matlab
fliplr( cumsum( fliplr(a) ) )

ungefär 18 timmar ago | 0

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Integration from 0 to a variable.
integral() is for numeric integration, but solve() is for symbolic work. fun2=@(x)((s-x).*((b/a).*((x/a).^(b-1)))/(1+((x/a).^...

ungefär 18 timmar ago | 0

fprintf to plot error

ungefär 19 timmar ago | 0

Divide .wav file into equal segments
The below will split all .wav in a given directory into 3 second buffers. A directory named after the file will be created insid...

ungefär 20 timmar ago | 1

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How can I make a non uniform quantization of an image?
If you have the Communications toolbox you can use quantiz() https://www.mathworks.com/help/comm/ref/quantiz.html You can also...

en dag ago | 0

MATLAB Online is not free; you need to have an active account of one of several kinds. If Harvard has a Total Academic Headcoun...

en dag ago | 0

Y axis in scientific form
If you are referring to the scale factor that sometimes get put up near the top of the Y axes, then the answer is that there is ...

en dag ago | 0

solve vs. fsolve
Sometimes plotting and finding intervals by eye is not productive. In the general case, theory says that it is impossible to c...

2 dagar ago | 0

Make matrix with loop
In the general case: xvals = [list of x values, does not have to be regularly spaced or even sorted]; numx = length(xvals); y...

2 dagar ago | 0

Plot Not showing all values
The max value of col2 is only about 20, but the maximum value of col1 is 992008 Near 210 the entries go like 21.4239 21.5239 ...

2 dagar ago | 0

Multi Threads operation SERIAL PORT in Parallel
That cannot be done with asynchronous serial ports such as RS232 and USB. In order to synchronize reception of data, you need to...

2 dagar ago | 0

how to insert value of array to other array
horzcat(). [list of values] is also horzcat()

2 dagar ago | 0

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What am I missing in this code I am trying to find roots of a System of Equation?
x=x+transpose(eps) That should be subtraction rather than addition.

2 dagar ago | 1

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Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.
inv(j)*f is going to return a column vector. Your original X0 is a row vector. Since R2016b, if you subtract a row vector and a ...

2 dagar ago | 1

Function that calls another function in LiveScript
Yes, provided that you are using a MATLAB release new enough to support functions in Live Scripts (which you are.) Note that th...

2 dagar ago | 0

cumulatives of the dynamical system
You currently have a first order differential equation, diff(D,t) == x(t). When you use it with ode45 you would be using a funct...

2 dagar ago | 0

Efficiently ways to solve for multiple for loops, of which the indices are the parameters of a function
You can do at least part of it in vectorized form. The following deliberately creates random numbers in the same order as if yo...

3 dagar ago | 0

How do I define an empty table of unknown size?
Sorry, variables that do not exist do not have any datatype. As you add variables to the table, the datatype associated with t...

3 dagar ago | 0

upper case need help
str=char(mod(double(lower(str))-97+shift,26)+97);

3 dagar ago | 0

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You are correct, this can happen. The slowdown is inside the symbolic engine, when it is asked to convert into a character repre...

3 dagar ago | 0

How to extract the events which have more than 3 consecutive rows
r=3; how many repeats mask = idx3.' == 2; %row starts = strfind([false mask], [0 ones(1,r)]; stops = strfind([mask, ...

3 dagar ago | 1

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Error detected but matlab did not specify the type of error. pls help out
m25 = Mb.*Nb(1-(0.5.*(c4(i)+c4(i+1))))-((1-(0.5.*(c1(i)+c1(i+1)))).*beta1.*(x2(i)+h2.*m12)+(1-c2(i)+c2(i+1)).*beta2.*(x3(i)+h2...

3 dagar ago | 0

R1=a*[0:n-1]; R2=b*[0:n-1]; R2=rand(1, 1, 100000)+R2.'; % add rand to every element in R2 del=R1-R2 ; % "row vector-column ...

3 dagar ago | 0

Suppose that you are required to build a function f(x,y), and you happen know it will be called with y = 19, but you write the c...

3 dagar ago | 0

subset the plot for the subset of x range
See isbetween() or use find(date_vector < last_date_to_plot, 1, 'last') in order to find the end of the group. In the special c...

3 dagar ago | 0