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# Star Strider

##### Last seen: Today
13,791 total contributions 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.

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How to make rectangular train?
See if the pulstran function will do what you want.

6 hours ago | 0

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How to do a surface plot with tangent plane?
I believe the problem is that you need to vectorise the function, using element-wise operations in the multiplications and divi...

7 hours ago | 0

add text to value of a plot, part 2
That needs a different approach. Try this: x = 1:10 y = rand(1,10); figure plot(x, y) xt = get(gca, 'XTick'); xtklbl...

8 hours ago | 0

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what is the error "must return a column vector."
The ODE function must return a column vector. I have no idea what ‘I’ is, however defining it as I do here, the code runs witho...

14 hours ago | 0

add text to value of a plot
if you have R2016b or later, use the xtickformat function to do what you want. Example — x = 1:10 y = rand(1,10); figur...

16 hours ago | 0

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Plotting multiple repetitions in one graph
See for example: Positioning a cutted signal from a ECK Signal since that EKG signal is reasonably close to the sort of signal y...

19 hours ago | 0

Problem with bsxfun and custom function
This runs without error: A = rand(4) B = randn(5) bsxfun(@na_div,A,B) function[out] = na_div(x,y); if isnan(x) & ~i...

22 hours ago | 0

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Local smoothing of peaks for a matrix
If you have R2018b or later, see if the rmoutliers function will do what you want.

22 hours ago | 0

Help me undersandand Frequency Vector and index vector in fourier transform
That is my code, so I will do my best to explain it. The frequency vector ‘Fv’ here defines the frequencies for a one-sided F...

1 day ago | 0

Why are the lines not showing up on my graphs?
You are only plotting one point (that being the last point) and it is not possible to plot lines with only one point. Try thi...

1 day ago | 1

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how to plot line with dots?
There are several options: x = 1:10; y = rand(1,10); subplot(3,1,1) plot(x, y, '-ok') title('Circles and Lines') subplo...

1 day ago | 0

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how can I present histogram as line plot
Set DisplayStyle to stairs.

1 day ago | 0

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how to model kinetic reaction system
There are several examples on fitting differential equations to data in Answers. See: ODE and Data fitting and Parameter Estima...

1 day ago | 0

Applying sgolay filter (derivatives) on data with variable Fs
Every signal processing technique that I am aware of (except the newly-introduced nufft function) requires uniformly-sampled sig...

2 days ago | 0

System of nonliner equations with symbolic variables
The code needs a few adjustments: syms lamT lamZ eqT = 10*lamT^13*lamZ^13 - 10/lamT^13 - 10*lamT^2*lamZ; eqZ = 10*lamT^13*l...

3 days ago | 0

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Is it possible to save a workspace when a program is paused without it ending the program?
Using the save function at appropriate places in the code will not cause the code to crash. See: How to save data from Geneti...

3 days ago | 0

'LSQCURVEFIT requires all values returned by functions to be of data type double' error
It took a bit of effort to figure out what you are doing, and get your code to run correctly, although it still needs for you to...

3 days ago | 0

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How to plot a symbolic equation
Using piecewise (R2016b and later versions) may be an option.

3 days ago | 1

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summation of 2 Sine waves
It does show a straight line at zero. Look at the magnitude of the y-axis (±2E-15), and you will see that it is essentially plo...

3 days ago | 0

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How can I create this image?
Try this: [X1,Y1,Z1] = cylinder; X2 = bsxfun(@times, X1, [1.2; 0]); Y2 = bsxfun(@times, Y1, [1.2; 0]); figure Ax = gca; ...

4 days ago | 0

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Sampling Audio at 11025 sample/sec in MATLAB
See: Record and Play Audio for a full description of the process. Note that SampleRate defines the sampling frequency.

4 days ago | 0

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I'm unable to derive a function with decimals
Use the vpa function: vpa(diff(Y)) .

4 days ago | 0

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Find missing dates from a file
Try this: fidi = fopen('Dates.txt'); D = textscan(fidi, '%{dd/MM/yyyy}D') fclose(fidi); AllDates = (D{1}(1):caldays(1):D{1}...

5 days ago | 0

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Help with some fft problems, can't come up with a better title
You need to force the index arguments to be integers. One option: plot(Y(1:fix(length(Y)/2))); There are others, dependin...

5 days ago | 0

How can I change the radius of the spiral so it varies along the length from 0 to 1?
Change ‘x’ and ‘z’ to: x=cos(y/100*10*pi).*(y/100); z=sin(y/100*10*pi).*(y/100); so the full code siis now: y=0:0.5:100; ...

5 days ago | 0

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How to get spectrogram of an array in MATLAB?
The documentation states that the input signal is ‘specified as a row or column vector’, so you would need to loop through each ...

5 days ago | 0

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Why can't I automatically get an integer from this simple function?
You have encountered floating-point approximation error. See Floating-Point Numbers for an extended discussion. The differen...

5 days ago | 0

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How can I find integral of a 3-D mesh field?
See if using trapz on one or both dimensions of your matrix will do what you want.

5 days ago | 0

Executing a multiple plot graph
Change to: plot(x, -1.2e8*a/25*x + 1.2e8*a) and it should work.

5 days ago | 0

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