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ODE15i DAE Warning:Failure at t=0.000000e+00. Unable to meet integration tolerances without reducing the step size below the smallest value allowed (0.000000e+00) at time t.
It can be deduced from your equations that the only possible solution for your DAE system is y(i) = 0 for i=1,...,8. Thus you c...

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Answered
Solver Stop Prematurely as new equation added
Use an options structure for "fsolve" as options = optimset('MaxFunEvals',100000,'MaxIter',100000) sol = fsolve(...,options) ...

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Please tell me what corrections can I make when encountering the following error?
We don't know the contents and sizes of the arrays you use. So we are unable to help. This would work e.g. : xspan = linspace(...

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Can I solve more than two PDEs in 2D?
If you have a licence for the PDE Toolbox, you can apply it to solve your problem.

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Iteration method of optimization
That's what I get from your description. But I might have misunderstood something. % Parameters m_values = linspace(0, 1, 100)...

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Answered
Error using surf (line 71) Z must be a matrix, not a scalar or vector.
Before your loop insert the commands size(squeeze(ws(:,:,1))') size(we_m) size(sn_m) For surf to work, all sizes must be the...

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Unknown variables appearing in solutions for symbolic equation solver
syms x f = x^5+x^4+3*x^2-4; solve(f==0) vpa(solve(f==0)) double(solve(f==0)) I have no explanation for the u that appears i...

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Answered
¿Por que me aparece el error de Incorrect number or types of inputs or outputs for function applyBoundaryCondition en mi codigo?
Instead of "edges", you have to include the edge number to which you want to apply the boundary condition. I plotted the geomet...

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Fitting multiple curves with multiple data sets, partial and globally shared parameters using lsqcurvefit
rng("default") b1 = 1; b2 = 0.85; b3 = 2.5; b4 = 1.1; b5 = 2.2; b6 = 4.5; b7 = 1.3; b8 = 7.2; b9 = 9.5; b10 = 0.5; %x data ...

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Answered
Why is this matlab program not able to solve accurately?
Some equations cannot be solved analytically because they are too complicated or because there are no functions available that c...

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Answered
I want to perform this time derivative?
From your description, you have 412 different dV_c/dt curves over time, one curve for each distance X. And now ? Do you want to...

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Answered
NLP problem with fmincon: Non-differentiable point in objective function
The solution variables for "fmincon" must be continuous in order to compute gradients, Hessians etc. Therefore, the solver is no...

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solving nonlinear wave equation
Using the method of characteristics, you get the equations dt/ds = 1 dx/ds = v_max*(1-2*rho/rho_max) drho/ds = 0 You should ...

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Answered
Is it possible to create a distribution fit (preferably gaussian mixture distribution model) for a distribution with precalculated bincounts?
The bincounts define a probability distribution. Draw random numbers from this distribution - they can be used as data in "fitdi...

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How can i solve this eqaution in matlab?
I still don't understand where you can change t=0.1 s, t=20 s, t=60 s, but here we go: Rho_f = 920; %kg/m^3 Dp = 0.152; % m m...

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How can i solve this eqaution in matlab?
Rho_f = 920; %kg/m^3 Dp = 0.152; % m m_dot_oxi = 7.95; %kg/s n = 0.75; m = -0.15; a = 2.006e-5; Rp = Dp/2; % m A = pi*(Rp...

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Answered
Finding accurate inverse of binary circulant matrix
BCM=readmatrix('MixingLayer.xlsx'); inv(gf(BCM,2))

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finding value in 2d array function of x and y
Given (vehicle.wheeltorque ,vehicle.wheelspeed), use pdist2 to compute the distances to the column vectors of the matrix [Torque...

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How do I sort these 2D-Points to get a proper surf plot of this function
x = linspace(-1,1,1000); y = linspace(-1,1,1000); [X,Y] = meshgrid(x,y); Z = nan(size(X)); idx = X.^2+Y.^2 <= 1; Z(idx) = 1...

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Answered
how to read mat file in matlab
https://uk.mathworks.com/help/matlab/ref/load.html

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Proving one function is greater than other?
syms x y f = 53.989/21.233 * (log(log(x))).^(4/3)./(log(x)).^(1/3); %x is solution where f starts getting greater than 1 xsta...

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Answered
Multicomponent gas separation in hollow fiber membranes
par.thickness_membrane = 1e-6; % thickness membrane [m] par.Perm_H2 = 250*3.35e-16; % Permeability H2 [mol m/m2 s Pa] par.Per...

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Answered
How should I set the value of u_tau?
The problem simply is that you cannot solve delay PDEs with "pdepe", at least not directly. A possible remedy: Call "pdepe" in...

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Calculate the summation of second column in both arrays
array = [2 5;7 -4]; sum(array(:,2))

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Function with multiple input parameters to be determined through fitting
You have to use "integral" instead of "int" and loop over the elements in E_p: EM_SS([1 1 1 1 1 1],1) function F = EM_SS(p, e_...

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Answered
How to solve a system of nonlinear differential equation that follows some pattern
function dy = fun(t,y) dy = y.*[y(2:end);y(1)] end or a function handle fun = @(t,y) y.*[y(2:end);y(1)]

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Interpolating the y values of a dataset A to correspond to the x values of dataset B.
The easiest way I can think of is y1_at_x2 = interp1(x1,y1,x2) If it's precise ? Define precise. At least you have the choice ...

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Answered
Hi, i try to solve equation c in terms of other variables, and its appear the messages and the answers is not as expected. Is supposed to be beta/p^(1/sigma)? is it?
Maybe you want to restrict the parameters to be positive (and thus real-valued): syms beta c sigma p positive eqn1 = beta/c^si...

ongeveer 2 maanden ago | 0

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How to solve 3 linear equations symbollically?
The first two equations in "velocity_eq" only have "omega_output_z" as variable and contradict each other (see above).

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Problem with matrix dimensions
In "sistema", I made F a column vector by adding a last line as F = F(:); and it works.

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