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How can I use Createpde to solve a fourth degree partial differential equation?
You have a system of two second-order differential equations. Thus instead of defining one equation, you have to define two and ...

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mono- objective optimization and multiopjective optimisation, I would like to use GA with option but there is a fault that I can't to resolve
You mean objective = @(x) 1.002 - ((1 - exp(-0.00003 * x)) ./ (0.00003 * (x + 1.5) + 0.00063 * (1 - exp(-0.00003 * x)))); a = ...

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How to place random CNT's in a box domain with random curves and orientation ?
https://uk.mathworks.com/matlabcentral/fileexchange/93250-generate-thick-fibers?s_tid=srchtitle

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how to use fmincon to optimize a functio with more than one control vector where the control vectors used in constrains also?
If all three vectors/matrices are to be treated as solution variables for "fmincon", use v = [p(:);X(:);L(:)] It's useful to t...

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Double Integration of Numeric Data - Acceleration -> Displacement
Assuming x(0) = v(0) = 0 in both cases, I get load("A2.mat") load("A9.mat") a2 = Datashort1; a9 = Datashort21; figure plot...

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Find real valued parameters of a complex equation/model by using optimization or curve fitting.
I don't know if this helps to get better results, but of course you have to fit real and imaginary part of mu_eff simultaneously...

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Storing while loop results in an array and plotting
Why do you think the results you get from the second part of your code are wrong ? g = 10; y(1) = 100; v(1) = 0; t(1) = 0; ...

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how to solve this error? Objective function is returning undefined values at initial point. FSOLVE cannot continue.
In the computation of c0,...,c10, you divide by x(3),...,x(13), thus by 0 because x0 = [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0] . After ...

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4th order Runge - Kutta vs. 4th order Predictor - Corrector
%--- Exercise 1 - A %--- Solving the diff. eqn. N'(t) = N(t) - c*N^2(t) with c = 0.5 using %--- Euler's method, Runge - Kutta ...

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4th order Runge - Kutta vs. 4th order Predictor - Corrector
For k>4, the variable RKN should no longer appear in the equations PredN(k) = PredN(k-1) + h/24*( 55*f(t(k-1),RKN(k-1)...

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Runge - kutta 4th order method for two different steps
y(j+1) = y(j) + h(i)*(K1 + K4 + 2*(K2 + K3))/6; instead of y(j+1) = y(j) + (K1 + K4 + 2*(K2 + K3))/6;

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Error using surf (line 71) Z must be a matrix, not a scalar or vector.
Works for me (assuming that FL_hat is 1001x1001 in your case): alpha = linspace(0, 2*pi, 51); beta = linspace(0, 2*pi,21); FL...

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How to avoid the warnings on my code
%--- Solving the diff. eqn. y'(t) = y(t) - c*y^2(t) with c = 0.5 using %--- Euler's method, Runge - Kutta method, and predictor...

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I am new to using Matlab, and wanted to ask if there is a way to group datapoints into bins/columns by numerical range? Thanks
https://uk.mathworks.com/help/matlab/ref/double.discretize.html https://uk.mathworks.com/help/matlab/ref/matlab.graphics.chart....

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Plugging a new value to ksdensity
rng("default") r = randn(100,1); x_new = 1.1; f = ksdensity(r,x_new) or rng("default") r = randn(100,1); f = @(x)ksdensit...

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which software better to learn?
If you ask this in a MATLAB forum, you will get a different answer than in a python forum :-) If you start learning about optim...

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Hello everyone, I have a question about numerical integration. The formula is shown below, where the integration path C_beta is a closed curve on the complex plane.
However, as mentioned in my question, the array list_beta forms a closed curve on the complex plane. Isn't then dq = q' dbeta a...

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graph is not showing
P=1; % assuming and constant Ex=20*10^4; Ey=2*10^4; Ea=0.1*10^4; k=0.1; t=0.01; b=0.05; h=0.1; ExGxy=17; Ah=((Ex/Ey)^0....

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Diffusion equation in Cartesian and Cylindrical coordinates
If m = 1, the condition at r = 0 set by "pdepe" is pl = 0, ql = 1. All other conditions make no sense mathematically because the...

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"Too Many Input/Output Arguments" error for nrlmsise00 function
The results for the defined testcase seem to coincide with what is stated in the Documentation (see below). You will have to ad...

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Weighted regression without priority zone, but with finding the minimum possible value for all the differences
x = [1 2 3 4 5 10 20 50].'; y = [5 10 15 20 25 30 40 50 60 90]; z = [265.110074796797 195.008035083193 156.258229529605 129.74...

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Code Matlab for a function that depends in a real parameter
integrand = @(f,y)y.*sin(f(y)); F_alpha = @(f,alpha,x)alpha.*x.*integral(@(y)integrand(f,y),0,1); f = @(u)u.^2; alpha = 1; x...

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Weighted regression without priority zone, but with finding the minimum possible value for all the differences
Use "fminimax". It minimizes the maximum error and is the nonlinear equivalent to minimizing the Inf-norm in linear regression p...

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Why am I getting error using assignin and syms while solving pde using pdepe
Here is the code for the dimensional model. It should be no problem to rewrite it in the non-dimensional form. Note that the s...

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Why am I getting error using assignin and syms while solving pde using pdepe
tau is a vector of values in your code: tau = linspace(0, tau_end, 100); % Non-dimensional time You can't use it as a symbolic...

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Andrica's Conjecture
Use nthprime(1:n+1) to generate the vector of the first n+1 prime numbers. The rest should be simple.

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Forward, Reverse finite difference question
x = 0:0.1:1; f = @(x)x.^2; derf = (f(x(2:end))-f(x(1:end-1)))/0.1; hold on plot(x(2:end),derf); % backward plot(x(1:end-...

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Time interation error while trying to solve a partial differential equation which describes pore diffusion resistance combined with with surface kinetics.
One error, one problem: The error: qr = De; must be replaced by qr = 1; because the boundary condition is given by p+q*f =...

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Numerical differentiation and integration
t = [0,5:10:115]; s = [0, 4892.3, 14041.3, 22371.3, 29926.1, 36764.4, 42965.4, 48634.8, 53910.3, 58961.8, 63981.6, 69165.5, 74...

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error in runge kutta -Unable to perform assignment because the left and right sides have a different number of elements.
You always have to use the variables at the ith time step, not the complete array in the assignments. I didn't check your compl...

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