Community Profile # 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.

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find the intersection of the four corner and trim the value out of the corner
Solve for the intersections, then plot to those limits — grid on syms stress1 stress2 shear12 SL_Ts=1800; SL_Cm=1400; ST_T...

3 hours ago | 0

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Integration of a function having constant parameter
Try this — syms a x F = int((4*a - 2*x + 4*a*x - 3*a*x^2 - 2*a*x^3 + a*x^4 - x^2 + x^3), x, 0, 1) Ffcn = matlabFunction(F) ...

4 hours ago | 1

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plot nonlinear equation in x y coordinate
Try something like this — syms x y SL_Ts=1800; SL_Cm=1400; ST_Ts=40; ST_Cm=230; SLT=100; k=((x^2/(SL_Ts^2))-((x*y)/...

4 hours ago | 0

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Interpolated contour plot with excel data
I’m guessing as to what ‘x’ and ‘y’ are, however it will be easy to reverse them if I guessed wrong. T1 = readtable('https...

4 hours ago | 0

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Try this — LD = load('conc.mat'); conc = LD.conc; t=[0;30;60;120;300;600;900]; figure plot(t, conc) hold on shadeWidth...

4 hours ago | 0

The differential equaton apparently does not have an analytic solution. Integrating it numerically is an option — syms y(x)...

9 hours ago | 0

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ode89 and ode78 are unrecognized in MATLAB 2021a
From the last line in the ode78 and ode89 documentation — Introduced in R2021b .

12 hours ago | 1

Find a y axis increasing point in a plot -
Try something like this — x1 = -2:2; y1 = [0 0 1 0 0]; x2 = linspace(-2, 2); y2 = interp1(x1, y1, x2); [maxy2,idx2] ...

12 hours ago | 0

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Error: This statement is incomplete.
I strongly advise against using eval. Put all of the arrays into a cell array, and then address them appropirately — year...

14 hours ago | 1

Locating z-values at certain x-values
I am not certain what the desired result is, sp[ecifically finding the ‘z’ values that correspond to ‘x_sea’ or the reverse. ...

15 hours ago | 0

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Weibull distribution plot x-axes scale is wrong
Try something like this — %% Weibull [parmHat, parmCI]=wblfit(Cont_Wh_Wp); scale= parmHat(1); shape=parmHat(2); figure...

16 hours ago | 0

Find roots of a first order differential equation
Try this — r = 1; x = linspace(-2*pi, 2*pi, 25); y = Function(x,r); zxidx = find(diff(sign(y))); ...

17 hours ago | 0

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Problem with multi-layer antenna design using Antenna Designer
The ‘Index cannot exceed 0’ message indicates that there is nothing in the array being indexed (it is empty, indicating that it ...

24 hours ago | 0

this plot3 looks 2D on live script (pointing downwards as it should), and 3D (pointing sideways for no reason), why?
I cannot run that since the data are missing. However to see it in all its 3D glory, use the view function to rotate the came...

1 day ago | 0

Array Indexing and Function Handling question.
It would be necessary to define ‘F’ in terms of a single parameter vector — F = @(xy) [3*xy(1)+xy(2).^2 , xy(1).^2+3*xy(1)-1];...

1 day ago | 1

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How to put endpoint on Bar graph
In R2021b, this is straightforward (and described in Specify Labels at the Ends of Bars). y = [75.8 78.05; 81 80.30; 91 80...

1 day ago | 1

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how can I change my time so that it takes frequency 1/250 hz
If is the sampling interval, multiply it by the sampling instants to convert them to time — C = readtable('https://www.math...

1 day ago | 0

How to plot color ball use matlab?
This is an interesting problem! This should get you started — Facets = 40; numPatches = fix(Facets/5); [X,Y,Z] = sphere(F...

1 day ago | 1

split an audio file
Unless it is absolutely necessary to use reshape, use buffer instead. It is just easier. It only operates on one vector at a...

1 day ago | 1

matlab font 2021b
There is likely a way to set this programmatically, however the easiest way to change the fonts is to click on Preferences, then...

1 day ago | 0

How do I increase the x-axis to make my action potentials bigger
The X-limits need to be reduced in order to show the detail, and the last subplot needs to have its axes rescaled to show the de...

2 days ago | 0

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Symbolic ODEs aren't symbolic?
Because of the ‘R*s’ terms, the system is nonlinear. The vast majority of nonlinear differential equations do not have analytic...

2 days ago | 0

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How to calculate the duration of data points in days

2 days ago | 0

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Error in ode45 (line 115) and odearguments (line 90)
There were two errors. First: dydt(2)=y(2)*(1-y(2))*((y(1)*(or*rr-br*re)-ar*rr); ↑ ← EXTRA UNMATCHE...

2 days ago | 0

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How to avoid using a loop here?
One approach — N = 5; tic [m,n] = ndgrid(1:N); A = 2*N + 1 - (m + n) toc Compare — tic A = zeros(N); for m = 1:N ...

3 days ago | 0

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Timeformat from HH:MM:SS to HHMMSS
Try this — time = datetime('12:30:00', 'InputFormat','HH:mm:SS', 'Format','HHmmSS') .

3 days ago | 0

Replace comma with dot after fopen
For MATLAB versions R2019a and later, the readmatrix function permits definition of the 'DecimalSeparator' (see the Text Files O...

3 days ago | 0

How to solve an ODE calculating the value of a variable inside a loop?
The problem is: x0 = X(end); so the error only occurs after the first iteration. The solution is: x0 = X(end,:) and thi...

3 days ago | 1

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