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Star Strider


Last seen: Today
13,120 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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Answered
Solving for a variable in equation
Use a root-finding function (I chose fzero here), then take the known variable values, create an anonymous function from the exp...

2 hours ago | 0

Answered
How to find data values that falls on line connecting loglog plot in matlab
To get a smooth interpolation, it is necessary to do two transformations on it. First, interpolate log(y), and then take the ex...

2 hours ago | 0

Answered
Magnitude, row and column in a Matrix
Try this: A = [87.97 87.97 17.97 95.22 87.96 91.26 75.50 75.50 75.50 78.13 64.89 78.90]; ...

6 hours ago | 0

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Answered
How to solve non linear system of ODE
If you are fitting the differential equations to data, see Monod kinetics and curve fitting and Parameter Estimation for a Syste...

6 hours ago | 0

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How do I obtain the derivatives after interp2 with the 'spline' option?
To get a numerical derivative, use the gradient function. With a matrix input, request two outputs. See Contour Plot of Vect...

7 hours ago | 0

Answered
How to plot a two variable function?
Apparently ‘x’ is a vector. That means that ‘z’ produces only two values. You could plot it as: figure plot(z, 'p') howe...

7 hours ago | 0

Answered
Easiest way to skip a few lines and then read data from this text file ( x and y) to draw a plot.
The easiest way I can think of is to use the dlmread function: filename = '6in_nomass_5.txt'; Data = dlmread(filename, '\t', ...

8 hours ago | 0

Answered
X,Y data of irregular grid, scatter plot with Z data
It is not obvious to me what you want. You already appear to have tried reshape, although I have no idea what the arguments ...

9 hours ago | 0

Answered
How do I synchronize stress-strain data?
If you want both of them to have the same sampling frequency, use the resample function on one of them. That will make the proc...

10 hours ago | 0

Answered
How to find the best parameters to fit damped oscillations curves
See: How to filter noise from time-frequency data and find natural frequency of a cantilever? Specifically: D = load('Lo...

13 hours ago | 0

Answered
fminsearch for fitting a function to experimental data
There are several errors in the posted code, as Walter noted, mostly involving implicit multiplication, that MATLAB does not rec...

14 hours ago | 0

Answered
Interpolate Data and find the matching x-Value
Try this: data=[1 2, 2 3, 3 3, 4 5, 7 9]; xval = @(yval) fsolve(@(x) interp1(data(:,1...

14 hours ago | 0

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Answered
Why ('t=(2x+1)/(2x-2)','x') is unsolvable?
Correct syntax: syms t x solve(t==(2*x+1)/(2*x-2),x) producing: ans = (2*t + 1)/(2*t - 2)

23 hours ago | 0

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Answered
Wrong FFT for an audio file
The plot is correct. You are not considering the exponential multiplication at the right end of the frequency axis. This mak...

1 day ago | 0

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Answered
How to conditionally change values in a table
Try this: val1 = {1, 2, 3, 4, 5, 6, 7, 8, 9}.'; val2 = {1, 3, 2, 1, 1, 4, 1, 1, 3}.'; t1 = table(val1, val2); lidx = ([t1.v...

2 days ago | 0

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Answered
Seperate yyyymm to mm-yyyy
Try this: ym = [201910 201911 201912 202001]; % Numeric (?) yms = compose('%6d',y...

2 days ago | 0

Answered
How to compare data
If they both have the same distribution (regardless of what that distribution is),and you are comparing two samples, the ranksum...

2 days ago | 1

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Answered
How to plot power law velocity profile
It plots the values correctly. Note that since ‘d’ and ‘r’ are the same, this part of the expression: (d.^((n+1)/n)-r.^((n+...

2 days ago | 0

Answered
Zeros on [b,a] output of butter filter
The filter is unstable. This can easily be remedied by converting to zero-pole-gain realization, and then second-order section ...

2 days ago | 0

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Answered
call dsolve() equation as function for reference.
Try this: syms A(z) B0 = 400; N = 1000; beta = 0.51; gamma = 0.5; Tend =100; cond = A(0) == B0; eqns = diff(A,z) == be...

2 days ago | 0

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Answered
Get a three column matrix from meshgrid data
Add one line: x=linspace(0.1,0.3,3); y=linspace(1,3,3); [x1,y1] = meshgrid(x,y); z=x1.*y1; C = [x1(:), y1(:), z(:)] to p...

3 days ago | 0

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Answered
Output argument "XXX" (and maybe others) not assigned during call to "function".
First — Please do not use global variables! They create more problems than they aolve, and can make code very difficult to debu...

3 days ago | 0

Answered
Non-linear Multivariate regression using genetic algorithm
One (very basic) approach: xd = rand(10,1); ...

3 days ago | 0

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Answered
Change axis colour matlab
Try this: x = linspace(20, 50, 29); y = sin((x-20)/30 * 2 * pi); figure plot(x, y) xt = xticks(gca); xt2 = compose('%.0...

3 days ago | 1

Answered
how to format a column of numbers into strings for ticklabel use?
Use the compose (or sprintfc) function to create a cell array: x = linspace(20, 50, 29); y = sin((x-20)/30 * 2 * pi); figu...

3 days ago | 0

Answered
how can i make this loop?
No loop needed. If you want to calculate ‘A’ with ‘a’ and ‘b’ already defined numerically as scalars, or if ‘b’ is a vector t...

4 days ago | 0

Answered
Change value for another value
Consider this example: A = [99999 rand(1,2); rand 99999 rand; rand(1,2) 99999]; B = A; B(A == 99999) = 0 producing: A = ...

4 days ago | 2

Answered
Inter-rater reliability
If I understand what your data are and what you want to do, The correct test for your data is Fleiss’s kappa statistic. As I re...

4 days ago | 0

Answered
Edge distortion when resampling a signal
From the documentation: ‘When filtering, resample assumes that the input sequence, x, is zero before and after the samples it ...

4 days ago | 0

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Answered
3D Plotting in matlab
I assume ‘complex’ just means complicated, and not a function with real an imaginary arguments or output. If it is actually com...

4 days ago | 1

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