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Star Strider

Last seen: Today Active since 2012

Hic sunt dracones! PROFESSIONAL: Physician (M.D.): Diplomate of the American Board of Internal Medicine; M.Sc. Biomedical Engineering: Instrumentation, Signal Processing, Control, System Identification, Parameter Estimation NON-PROFESSIONAL: Amateur Extra Class Amateur Radio Operator; Private Pilot, Airplane Single Engine Land, Instrument Rating Airplane; Gamer NOTE: I do not respond to emails or personal messages, unless they are about my File Exchange contributions. Time Zone: UTC-7 (Standard); UTC-6 (Daylight Savings/Summer)

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Fit parameters to a non linear differential equation of second order
Supply your own variables for ‘t’, ‘Q’, ‘w’, and ‘H’, and then try this — syms a b c d H L Q(t) w t Y DEq = L*diff(Q) =...

ungefär 14 timmar ago | 0

How to transform the normalized values of a histogram (i.e. the bars heights) in percentages?
Altering the histogram plot is likely not possible because the ‘Values’ vector is read-only. The easiest approach is likely t...

ungefär 15 timmar ago | 1

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Patch function doesnt shade the second plot.
One of those vectors in the second plot likely has at least one NaN value. Try something like this — meanNDtest = fillmissi...

en dag ago | 1

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How can I display numbers in scientific notation but in magnitudes of 3 and to 3 significant digits?
I wrote a little utility function for my own use a while back to do that. Try this — engstr = @(x) [x(:).*10.^(-3*floor(log...

en dag ago | 0

I am getting incorrect FFT values
The 1.86 value is correct. Look at the time domain plot — %FFT T=0.01; %cuz the time interval is 0,01. You can see in "t" ...

en dag ago | 0

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Solve a system of 3 second order equations
This should get you started — syms c_1 c_2 k_1 k_2 k_n k_nl J_1 J_2 J_n theta_1(t) theta_2(t) theta_n(t) theta_out(t) t Y d1...

en dag ago | 0

mesh or surf from x y z coordinates
I am not certain what you want. One approach — LD = load(websave('swarm','https://www.mathworks.com/matlabcentral/answers/u...

en dag ago | 0

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Fill light gray color between two horizontal lines in a plot?
To plot a ‘dash-dot¹ line requires a slightly different LineStyle definition — x=[1:10]; y=[1:10]; figure(1) plot(x,y,'b') ...

en dag ago | 0

‘The solution in an opaque manner could be working out for me perhaps, how can I do this?’ The default background colour is 'no...

2 dagar ago | 0

I Want to solve system of three differential equations numerically. How can i solve it with ode45, or are there any other ways?
syms v1(t) y1(t) y2(t) v2(t) a2(t) phi(t) L r A B C D E F G H I J beta Omega(t) Omegaac(t) omega(t) omegaac(t) Y t sympref('...

3 dagar ago | 0

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import data from csv and plot it
I opened it in Excel, did a straightforward manual copy-paste to Notebook, and saved it to a text file (that I uploaded here). ...

3 dagar ago | 1

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x values when taking a numerical derivative
‘I think (correct me if I'm wrong) this can be done by diff(y)./diff(x)’ Not actually wrong, simply mistaken with respect to ...

3 dagar ago | 0

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Plotting surface tangent to surface plot
The code defines ‘x’ as a scalar: x=linspace(-9,0.5,1); with one element equal to 0.5. That creates ‘X’ and ‘Y’ as vectors...

3 dagar ago | 0

How do I change a date in a cell into three cells in MatLab xlsx file?
After using readtable to import the Excel file, try something like this — T1 = table(datetime('now') + days(0:4).', rand(5,1),...

4 dagar ago | 1

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How can i find the co-ordinates of a point where the slop is -1 in below graph ?

4 dagar ago | 2

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Improve part of code using a loop
One approach — date_time = (datetime('01-Jan-2023') : caldays(1) : datetime('31-Dec-2023')).'; Values = randn(numel(date_time...

5 dagar ago | 0

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How to plot 2 columns (one is population the other is years) in a linear graph
This is difficult without the Excel file. Taking a wild guess: plot(Population.years, Population.Population) alternatively...

5 dagar ago | 0

Unclear periodicity output with daily temperature dataset using periodogram
I have no idea what temperature is being measured. I would expect environmental temperatures to have a significantly wider rang...

5 dagar ago | 0

Why is my FFT diagram has a slope approaching to zero?
It looks correct to me. I made three changes: indexing into the table and references to it, subtracted the mean from ‘S’ since ...

5 dagar ago | 0

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Filtering between frequency range
The function you use depends on how you want to filter them. The filtering functions (includijng filtfilt) operate column-wise ...

5 dagar ago | 0

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Adding scatter points to a contour plot
‘Highest’ usually implies one value, not 67, and without your data (the (67x67) matrix) and understanding what the ‘highest 67 v...

6 dagar ago | 0

For each peak, I would like to calculate the delta (shown in image) for the plot in the script at each threshold level in a table.
@Rufus Adjetey — Try my code — X = [0.0318400000000000,0.0368000000000000,0.0417600000000000,0.0467200000000000,0.0516800000...

6 dagar ago | 0

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How to locate X value for a given Y value
In the absence of the data, getting an independent variable valuex ‘x’ from an dependent variable value ‘y’ is relatively straig...

7 dagar ago | 0

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How do I make a bar graph from uneven arrays without adding zeros to the end of the smaller array?
I am not certain what you want. This approach creates a NaN matrix with the column length of the larger vector, writes the or...

7 dagar ago | 0

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Convenient way to filter sinusoidal noise from decay data?
If you want to use a frequency-selective filter, first do a fft of the data to determine the frequency components, then use the ...

9 dagar ago | 0

How can I get a smooth curve in MATLAB?
One option is to interpolate to a finer ‘x’ vecttor, and then use a method such as 'pchip', 'spline', 'makima', or others to do ...

9 dagar ago | 0

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We do not have your data. The fliplr function will not produce the desired result with column data. I prefer to use the patc...

9 dagar ago | 0

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How to use the data from a .mat file to make a graphic?
Use the load function to ‘read’ the .mat file. (I always load into a variable as a structure of the .mat file contents so that ...

9 dagar ago | 0

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A way to write "if x is in y matrix do this"
It depends what the random number is, and how you define ‘y’ . The ismember function works for exact comparisons. The ismember...

9 dagar ago | 0

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