Star Strider

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15,337 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

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Answered
How to create a Symbolic vector
Try this:: n = inputdlg('Enter the length of the vector (integer): '); n = str2double(n); syms x x = sym('x',[1 n]) pro...

5 hours ago | 0

Answered
1D interpolation by y = ax+b
To set the start point at the origin (0,0), calculate the slope as: slope = x(:) \ y(:); for example: x = 0:0.1:10; y = ra...

5 hours ago | 0

Answered
A little question of [] and for loop
The full code should actually be: A = []; for i=1:50 A=[A i]; end It works by concatenating the value of ‘i’ to existi...

6 hours ago | 1

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Plot surface from non-anonymus function
See if this does what you want — function z = test(w) x = w{1}; y = w{2}; z = 2*x.^2 + 2*y.^2 +10*(1.1*y.^2 +...

18 hours ago | 0

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Answered
Find distance between one point and a subset of other points.
See if the pdist function will do what you want. (If so, squareform may also be useful.)

22 hours ago | 0

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detrending timeseries by removing the linear function fitted by samples?
Considering that the objective is to remove a linear trend, perhaps the easiest way would be: t = 11:22; p = polyfit(x(t),tac...

23 hours ago | 0

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Find peak and plot graph from peak
I am not certain what you want to do. If you want to get the peaks and their indices, request those outputs: [pks,locs] = f...

1 day ago | 0

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How can I define a gradient function that can update k values after each iteration to optimize parameters in ODEs?
One option is the approach in Parameter Estimation for a System of Differential Equations. You will need to modify the ‘kinetic...

1 day ago | 0

Answered
How to draw bar graph of different colors ?
Try this: y = [280 260 240]; figure c = bar(y); set(gca, 'XTickLabel',{'CS0','CS10','CS20'}) xlabel('Wt% of cenospheres'...

1 day ago | 0

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Problem to get the right format of a Surf Plot
It looks as though ‘X’ is not sorted. Without the data a guess would be this possible solution: BB = sortrows (BB,1); See th...

1 day ago | 0

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Answered
How to linearly fit a semilog graph
Try this: D1 = readmatrix('Data.xlsx'); x = D1(:,1); y = D1(:,2); [ymax,idx] = max(y); idxrng = idx:numel(y); objfcn ...

1 day ago | 0

Answered
I don't understand why the elements are not the same on both sides
The reason is that ‘t’ needs a subscript: x(n+1) = x(n) + h * ((8*(x(n))/(t(n)+1))-(t+1)*(x(n)^2)); ...

1 day ago | 0

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Answered
Adding a new column to a table
One approach: T1 = table(randi([330 470],10,1), 'VariableNames',{'QTcorrected'}); % Create Data QTc = @(x) 1*...

3 days ago | 0

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Answered
How to Segment EMG data into time intervals
One option is the Signal Processing Toolbox buffer function. It uses samples as one of its arguments, however that is straigh...

3 days ago | 0

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Answered
Coupled rate ODEs with ode45
The concentrations change appropriately, however they don’t change much and the concentrations are vanishingly small. That’s th...

3 days ago | 0

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Answered
Figure line won't connect/display all data points
Isolated points only plot if specified as markers. Try this: D1 = load('midpoint.mat'); midpoint = D1.midpoint_overlap_seq...

3 days ago | 0

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Answered
How to solve this equation?
Probably the easiest approach: syms h z2 Eqn = h^0.66+0.0805*h == 0.045; [h,prms,cndx] = solve(Eqn,h, 'ReturnConditions',1)...

3 days ago | 0

Answered
ode45: use span of length 2
The tspan argument can be anything you want it to be (within limits). To have ode45 to evaluate and output at only those valu...

3 days ago | 0

Answered
confusing error message: 'Not enough input arguments'?
With a function in that format, it is necessary to pass a function handle to lsqnonlin (or any other function that takes a funct...

3 days ago | 0

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Answered
How to plot only the real solutions of an implicit function ?
Nothing is being generated: R = 0.35; L = 0.25; H = 0.4; f1 = @(x,y) sqrt(L^2-(R*(cosd(x)-sind(x).*sind(y))-H).^2); figu...

4 days ago | 1

Answered
Plot and calculate Damping ratio
The findpeaks or islocalmax functions can return the information to do the calculations.

4 days ago | 1

Answered
Trouble taking the differential of a function
‘What am I missing here?’ Most likely, using the Symbolic Math Toolbox. Try this: syms E I L w_0 x func(x) = (((w_0*L)...

5 days ago | 0

Answered
Help with Errorbars on Bar Graph
Try this: AngleFlex90 = [95 99; 93.33 80; 95.67 99.33]; AngleError = [8.9 6.6; 7.6 5; 4 1.2].'; figure hBar = bar(Angle...

5 days ago | 0

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Answered
Gaussian Fit for x and y data
Try this: D1 = readmatrix('Test1.xls'); x = D1(:,1); y = D1(:,2); gausfcn = @(b,x) b(1).*exp(-(x-b(2)).^2/b(3)); [maxy,i...

5 days ago | 0

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Answered
Shade the region between the lines and xy axis
Try this: x=linspace(-2,8); y1=@(x)(8-2*x); y3= @(x)(5+2.5*x); y4=@(x)(0*x); y5=xline(0); y1_xint = fzero(@(x) y1(x), 1);...

5 days ago | 0

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Answered
Find index of value in array
It is not obvious to me how the number of subjects and the repitition time interact, however it is unlikely that a loop is neces...

5 days ago | 0

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Answered
what is the reason of an empty diagram?
It is likely necessary to index the variables appropriately. Try this: xdot10=-(1/m_c)*(k_ss*(x(:,9)-x(:,5)+r*x(:,7))+c_ss*...

5 days ago | 0

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Answered
Need help solving a system of 2 second-order differential equations using ode45
I am not certain what you want. This assignment: thetaVec = deval(thetaVals,tVec,1); returns the value of ‘theta’ for the ...

5 days ago | 0

Answered
how to solve 2nd order coupled system of differential equations with heaviside function using ode45 solver?
Numerical ODE solvers do not do well across non-differentiable discontinuities. The heaviside function in MATLAB is differentia...

5 days ago | 0

Answered
Convert Excel to Timetable
‘I attached the excel sheet as well ...’ Not yet. The readtimetable function may be appropriate if you have R2019a or la...

6 days ago | 0