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Numerical Solution to second order coupled system of boundary value equations
Use MATLAB's bvp4c.

4 years ago | 0

Answered
How to find all cycles of specified length of given graphs?
Find all cycles and evaluate their lengths afterwards separately: https://de.mathworks.com/help/matlab/ref/graph.allcycles.html...

4 years ago | 0

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Answered
How to solve 2d steady state PDE? Temperature is a function of radial and axial direction
Use MATLAB's "pdepe" and interprete the axial coordinate z as the time coordinate t.

4 years ago | 0

Answered
Proper way to write ode45
The usual way is to use arrays in which you can write and from which you can read variables at certain positions. Or you can us...

4 years ago | 1

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Answered
fminbnd not working for a single variable optimization problem
k1=fminbnd(@(k)valfun3(k,k0,z0,a0),kmin,kmax); instead of k1=fminbnd(@valfun3,kmin,kmax);

4 years ago | 0

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Answered
What to do with for-while loop?
number_on_dice = 6; bu = [ ]; while number_on_dice ~= 8 u = rand(); number_on_dice = sum(cdf <= u) + 1; bu = [b...

4 years ago | 0

Answered
Help regarding below question.
f = @(x) [functional equation] syms x df = diff(f,x); df_fun = matlabFunction(df); x = xstart:0.01:xend; % define interval ...

4 years ago | 0

Answered
Why ode45 returns NaN for a system of differential equations?
N = 10; Mi = zeros(N,1); c0 = zeros(N,1); Mi(1) = 14.01; c0(1) = 0.7809; Mi(2) = 16; c0(2) = 0.2095; Mi(3) = 39.95; c0(3...

4 years ago | 0

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Answered
calculate the rectified value
built_in_value = mean(abs(A(:)))

4 years ago | 1

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Answered
How to code a nonlinear vector-valued function so that it fits the coordinate grids (xq , yq) of triangles?
Here is the author's homepage: https://people.sc.fsu.edu/~jburkardt/ Just contact him.

4 years ago | 0

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Answered
Index in position 1 is invalid. Array indices must be positive integers or logical values. Error in explicitftcs (line 28) u(Nx+1,k) = 1.; >> u(Nx+1,k) = 1.; Index in
Nx should be the number of grid points in x-direction, not the length of these intervals. You mixed this up by setting Nx = 0.1...

4 years ago | 0

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Extract positive value from solve function
If a and b contain no more symbolic constants, then you can use a = double(a); b = double(b); a = a(abs(imag(a)) < 1e-6); b ...

4 years ago | 0

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How to Solve system of nonlinear PDE
Looks better, doesn't it ? Tin = 445; % Feed concentration L = 17; % Reactor length ...

4 years ago | 0

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Answered
How to plot a set as the constraint in 2D?
syms x y f = sqrt(x^2+y^2); ezplot(f, [0 10 0 10])

4 years ago | 0

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Store function results from for loop
i = 0; for do_shaft = .04:.001:.14 for h = .01:.001:.10 for w = .01:.001:.10 Nf = func(inputs) ...

4 years ago | 0

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Answered
Finding global minimum with rand
fumin = Inf; for i = 1:100000 u = -6 + 12*rand(3,1); fu = f(u); if fu < fumin umin = u; fumin = fu; end...

4 years ago | 0

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Answered
Check if function handle is nonlinear with Matlab
Call your function handle f with symbolic vectors x and y and a symbolic scalar a and check whether f(x+y) - (f(x) + f(y)) - f(...

4 years ago | 1

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Answered
Solving a nonlinear system differential equation using symbols
Here is the sequence of commands to obtain the solution in Octave. One can use the "solve" directly for all variables, but I de...

4 years ago | 0

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estimation of parameters by using lsqnonlin for system of differential equations
[B,resnorm,RESIDUAL,exitflag,OUTPUT,LAMBDA,Jacobian] = lsqnonlin(@Kinetics,B0,time,A_data,lb,ub,options ); This is not the corr...

4 years ago | 1

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how to write hyper geometic function
https://de.mathworks.com/help/symbolic/hypergeom.html

4 years ago | 0

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Obtaining values for variable on the left and right hand side
You can't achieve 0=0 since 0.5 / (1 + 0.2 * (x2)^2) is always positive. But if you choose x1 = (0.5 / (1 + 0.2 * (x2)^2))/(...

4 years ago | 0

Answered
How do i use ode23 if i have a spline function?
Ta = 273.15 + 10; fun = @(tt) ppval(spline(t,k),tt); fun_ode23 = @(t,T) fun(t)*(T-Ta); T0 = 273.15 + 50; tspan = [0,1]; [t,...

4 years ago | 0

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Answered
ODE45 solving rate too low
I can't see something wrong in the equation itself, but of course I don't know if the inputs have the correct units etc. But fo...

4 years ago | 0

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inserting index for variable
I don't know what you mean by "I want make index for my variable", but x = 8; b = 9; w = zeros(2,1); u = zeros(2,1); for i ...

4 years ago | 0

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Bayesian Optimization for constrained optimization in fmincon?
I have been doing constrained optimizations of underdetermined systems of linear equations with fmincon. Isn't "lsqlin" the app...

4 years ago | 2

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making pde matlab code
Here is a simple code to check your results from pdepe: % Spatial interval L = 1; nL = 101; dL = L/(nL-1); eta = linspace(0...

4 years ago | 0

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Can I use custom sum of two mean sum square cost functions for lsqnonlin?
Your output must be output = [(RecPar1(:) - TruePar1(:)) / sqrt(length(TruePar1)) ; (RecPar2(:) - TruePar2(:)) / sqrt(length(Tr...

4 years ago | 0

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Answered
Solve function:Error using sym/solve>getEqns
"qfunc" does not accept symbolic input, and your B is symbolic.

4 years ago | 1

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solving an ODE with a constraint equation
As you said: You will have to couple a nonlinear solver with an ODE integrator. I changed the ODE to dy/dx = a*x because of the...

4 years ago | 0

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Answered
Sine equation in Euler Method ODE
% 2D SYSTEM SIN-COS EQUATIONS USING FORWARD EULER METHOD % solve u'(t) = F(t,u(t)) where u(t)= sqrt(t+1)*cos^2(t),sqrt(t+1)*sin...

4 years ago | 0

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