# Walter Roberson

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 T0099000; if you are waiting on a reply from me for an older issue, please send me a reminder.

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**Content Feed**

Problem running my first program

fsolve(@NL_Syst_HW4, [0,0,0]) Remember that matlab processes arguments before making the calls. The argument NL_Syst_HW4 ha...

2 hours ago | 0

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How do I fix my variance? Can't figure out what wrong with my code because I keep getting NaN for my variance and y. If there anyway I could fix my variance or an easier way.

You had a persistent problem where you were assuming that var() of a vector would give you a result the same size as the vector....

7 hours ago | 0

A faster way to find the similarity between two signals

Maybe. It would not astonish me if parts if it could be rewritten to use an available GPU. However... the algorithm already inv...

8 hours ago | 0

How do I save the output array (y2) for each loop?

Under what circumstance could c be <= 0 such that the if would fail ? amultiple = input(sprintf('Enter multiple locations (0 - ...

8 hours ago | 0

how can I plot 3d in matlab

It would probably be easiest to just draw 3D lines using plot3() . And use grid on

1 day ago | 0

How to loop equations and expressions used by Dynare in matlab context?

%%%%%%%%%%%%%%%%%%%%%%%%%%%% rule ={ 'a=x;' 'b=y;' "c=rho+(" + newline + ... "@ # for i in number" + n...

1 day ago | 1

| accepted

How to solve a double complex ode using ode45 in MATLAB

The infinite boundary condition is a problem for symbolic solution: dsolve() rejects it. The 0 initial time is a problem: you d...

1 day ago | 1

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Matlab error using imagesc()

T=Dasdata.Time(channels); Your T is a column vector. dt=T(2:end)-T(1:end-1); That makes dt a column vector, because indexing ...

1 day ago | 0

Removing commas between columns in text data

test = {'Sometimes, ,, I, use, commas, .' 'I, like, writing, ,, I, like, reading'}; test = regexprep(test, {'(?<=[^,]),\...

1 day ago | 2

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griddata command returns all NaN values

for a = 1:100 X1(a) = (5/100).*a; X1 is linear in a. c = a/50; a is a double precision integer, 1 to 100. c is the inte...

1 day ago | 0

Sending four byte commands To serial port

cmd = [0x81 0x12 0x00 0x00]; write(YourPortObject, cmd, 'uint8'); response = read(YourSerialPortObject, 4, 'uint8'); if ise...

1 day ago | 0

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Integer eigenvalues in Matlab

Take the symbolic determinant of (matrix minus lambda) . Ask to factor() that. Look for the entries of the form (lambda +/- inte...

2 days ago | 0

I can't understand the following MATLAB code documentation

The implication is that the second part is stored in its own file.

2 days ago | 1

Count from 1 to 0 with increment of 0.01

You need to use a negative increment to count down from a higher value to a lower value.

2 days ago | 0

Equivalent python for a matlab line?

X = Y[z[i, 0:11],0] would be my guess. However, this relies upon the values in z having been changed to index 0 based instead ...

2 days ago | 0

What is the difference between [v' 1] and [v', 1]?

v = ((1:3) -(2:4)*1i).' [v' 1] [v', 1] You can see that even for complex numbers, [v' 1] and [v', 1] produce the same results...

2 days ago | 0

How can I sum each 3 columns array?

reshape(x, size(x,1), 3, []) now you can sum along the second dimension, and then reshape to remove the now-singular second di...

2 days ago | 1

MATLAB Compiler for a .mlapp that have a .m file

https://www.mathworks.com/help/compiler/unsupported-functions.html Functions Not Supported for Compilation by MATLAB ...

2 days ago | 0

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Increase number of parallel pools coworker by adding hardware?

Check your Parallel Preferences https://www.mathworks.com/help/parallel-computing/run-code-on-parallel-pools.html And check t...

2 days ago | 0

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Datetime doesn't work in uitable

Your reference to handles.file_table tells us that you are using GUIDE and "traditional figures". And in traditional figures, ui...

3 days ago | 0

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How can I split time series in a half?

ts1 = timeseries(rand(1,4096)); %official approach. uses indices ss2a = getsampleusingtime(ts1, 1, 2048); ss2b = getsampl...

3 days ago | 0

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Symbolic integration of Marcumq.

Using the online tool here, execution can get through the calculation of "outer", but the integrals might take a while. Could y...

4 days ago | 0

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give me invalid use of operator at U, why?

U = 0.75*exp(-((xmid-0.5)/0.1). 2)'; my guess is that you wanted U = 0.75*exp(-((xmid-0.5)/0.1).^2)';

4 days ago | 0

What should go in a next-generation MATLAB X?

The ability to assign a subset of fields to a struct (array) would be useful. It is common to want to be change a few settings, ...

4 days ago | 0

Finding global maxima and minima

Use calculas. The minima and maxima of a function can only occur at: Critical points of the function; or The boundaries that ...

4 days ago | 0

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stacking or appending tables with NaN and 'ABC' -- cell vs non-cell

If I understand correctly, you are looping reading multiple files, and want to put the results all into one large table. And tha...

4 days ago | 0

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一つの列の中の任意の範囲内に正と負の値が両方がある場合に、その範囲内の値を０に置換するにはどうしたらよいですか。

range = 3; A = [1,2,-3,4,5,6,7,8,9] A(A < range) = 0

4 days ago | 0

ODE15s Errors defining variable and ODE functions

Your equations involve components which subtract out T0 and P0. When you initialize the boundaries to T0 and P0 that results in ...

5 days ago | 0

Polynomial has more than one symbolic variable error

syms m1 m2 J1 s b k1 k2 k3 r1 xi T real t=0:0.5:100; A=[-s^2*m1-s*b-k2, k2, 0; -k2, s^2*m2+k3+k2, -k3; -s^2*J1/r1-s*b/r1, 0, 0...

5 days ago | 0