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Star Strider

Last seen: Today
13,795 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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solve vs. fsolve
Give fsolve different starting points, one positive and one negative: eqn1 = @(x) x.^2 - 4; for k = 1:2 a2(k) = fsolve(e...

3 hours ago | 0

Reordering column so the values match an already reordered column
I am not certain what you want to do. Note that the sort function has two outputs, the first being the sorted values and the ...

3 hours ago | 1

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Time in seconds ode45
Create the ‘tspan’ argument as a vector of more than two elements: tspan = 0 : 0.1 : 10; .

8 hours ago | 0

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Updating the parameter of ODE45
Actually, ‘f’ needs to be a (2x1) matrix, since there are two values of ‘x’, and they both need to be defined, so something like...

12 hours ago | 0

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

24 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...

1 day 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...

1 day 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...

1 day 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...

1 day 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...

1 day ago | 1

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...

1 day 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.

1 day ago | 0

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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...

2 days ago | 0

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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...

2 days 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...

2 days ago | 0

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

2 days 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...

2 days 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...

3 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...

4 days ago | 0

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

4 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...

4 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)) .

5 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...

6 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; ...

6 days ago | 0

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