# Star Strider

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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**Content Feed**

How to extract data with multiple headerlines locations, with a differing number of headerlines per file?

My apologies, however this has to be the most inelegant code I ever wrote. It has the virtue of being able to read the posted...

3 hours ago | 0

How can i replace a string to a numeric value in a specific column of an array ?

I am not certain if ‘string’ refers to character vectors or string variables. Try this — column = ['M';'B';'M';'M';'B';'B']...

13 hours ago | 0

Finding the turning point on the left side of a peak

‘... the turning point on either side of the major peak’ Those are referred to as the Q and S deflections (or waves). Th...

19 hours ago | 0

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Help. Plot graph calculation

A somewhat more analytic representation — x = linspace(-1, 3, 250); y = (x).*((x >= 0) & (x < 1)) + (2-x).*((x >= 1) & (x < 2...

19 hours ago | 0

Changing color of plot

Alternatively, using logical indesing — x = -10:.01:10; y = sin(x); dy = gradient(y); ...

19 hours ago | 0

Solving for angle (Beta) using vpasolve

That’s the result I get when I solve it (and then correct it by ) — M1 = 3; P1 = 1; theta2 = 5; thetha3 = 20; gamma = 1....

1 day ago | 0

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extract especific rows from matrix

One option — c = [202002041000 25 202002041015 35 202002041030 54 202002041045 ...

1 day ago | 0

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How can I get a time versus amplitude graph from the waveform.

The spectrogram function returns amplitude (the ‘z’ axis of the rotated surf plot) in units of dB/Hz, so it will not produce the...

1 day ago | 0

Issue with Quiver plot

I have absolutely no idea what the desired result actually is. One option: negate ‘x2’ Another option: set(gca, 'XDir','r...

1 day ago | 0

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How to use duration data in the x axis of a patch graph?

Post the code and post the MATLAB version you are using. Only in the last 2 releases (that I am aware of) has patch supported d...

2 days ago | 0

smooth step function with rise time

It occurred to me that one option would be filtering the original signal to ‘round off’ the sharp transitions. I first tried a ...

2 days ago | 0

What do I do next to solve for m?

The conditions only apply if the values of the constants are not defined first. Try this — syms f m g L I f = sym(0.1); ...

2 days ago | 1

dirac() and ode45 issue

I doubt that the dirac call is actually necessary. The code works correctly without it — tspan1 = 0:0.00000001:0.01; x0=...

3 days ago | 0

Trouble with symbolic integrals

Since the desired result is numeric, use vpaintegral — syms x; f = exp((x^2-1)/2)/(1-x^2)^0.5; int_f = vpaintegral(f,-1,1)...

3 days ago | 0

Plot figures in the same figure (MATLAB)

Add the second matrix to the code, concatenate it with ‘H’ along dimension 3, then use a for loop to address and plot them. H...

3 days ago | 0

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How to extract symbolic parts and corresponding constant values with division in symbolic polynomials?

I cannot find any function that would return the desired result, however ther are other options, a few of which are — syms x...

3 days ago | 0

How to plot multiple y values for a single x value

The plot function figures this out automatically — A = randn(512,10); x = 1:10; figure plot(x, A, '.') xlim([0 11]) ...

3 days ago | 0

INDEX IN POSITION 1 EXCEEDS ARRAY BOUNDS (MUST NOT EXCEED 3)

These — for i = 1 : n Sum = 0; for j = 1 : n should instead be — for i = 1 : size(a,1) ...

3 days ago | 0

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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 days 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) ...

3 days 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)/...

3 days 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...

3 days ago | 0

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Plot scatter plot as shade

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

3 days ago | 0

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please give me answer what is wrong

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

4 days 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 .

4 days 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] ...

4 days 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...

4 days 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. ...

4 days 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...

4 days 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))); ...

4 days ago | 0

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