Answered
Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.
Only a single number can be saved in an array element. But you try to save a vector ([a b(i) c 0 0 0 0 0 d(i)]) in a single e...

2 years ago | 0

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Answered
Runge Kutta 4th Order Method for an Equation
Write a function function dy = f(t,y) that accepts t and a vector y of length 2*n with y = [c_1;...;c_n,cbar_1;...;cbar_n] ...

2 years ago | 1

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How can I calculate the integral of Legendre function P(n,theta) ?
The Legendre function is a numerical, not a symbolic function in MATLAB. Further, it's define for -1 < x < 1. So integration f...

2 years ago | 1

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Answered
Plotting discrete Klein - Gordon equation (DKG) with friction in DNA
acceleration(1) = acceleration(numBases) = 0 for every value of i in your loop. From the equation initialVelocities = initia...

2 years ago | 0

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Answered
Trying to solve system of PDE by spacial discretization. Errors are coming frequent . what am i doing wrong ?
Technically, your code works now. But you get NaN values for some dydt's. The reason might be that you start with a complete 0 v...

2 years ago | 0

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Answered
I need help with an error I get
Define F before you call "funcao_forca". It's not set in your code. Maybe you mean F = funcao_forca(t,f); because f is a give...

2 years ago | 1

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Error in untitled22>solveHeatEquation1D (line 32) U(N+2,n+1) = beta(t); Error in untitled22 (line 11) [t, x, U] = solveHeatEquation1D(T, a, b,mu, u0,alpha, N, M);
a = 0; b = 1; % spatial interval T = 0.4; % end time mu = 0.5; % conductivity alpha = 1; ...

2 years ago | 0

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Why does the code always return "-ve" values?
When I run the main, it returns me all negative values though I have given only two negative values. Why not ? The objective is...

2 years ago | 0

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gradient descent optimization doesnt work in code?
My guess is that either "Energyconsumption" depends discontinuously on waypointTimes, that epsilon in the compuation of the grad...

2 years ago | 0

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Do you need to initiate symbolic variables in a script if you will be calling for a function using those symbolic variables?
You need to define all variables in the calling program that are not being explicitly passed from the function, but that you hav...

2 years ago | 0

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Vector with symbolic variable
Works for me. psi = sym('psi',[8 1]); t = 1:1000; psi(t(5))

2 years ago | 0

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4.2 Whiteboard Coordinate System Error for Function
This arithmetic operation is not defined in MATLAB: 2\*pi

2 years ago | 1

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Error: File: untitled5 Line: 19 Column: 1 Function definitions in a script must appear at the end of the file. Move all statements after the "f" function definition to before
Your interval of integration is complex-valued. I used nested functions to make the parameter g visible in your "f". And I ass...

2 years ago | 0

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Error using fmincon and integral2: taking integral variables theta and p as an array while performing computation
Take care that you pass k, c and d1 as values, not as function handles to your objective function. Thus (as in all your questio...

2 years ago | 0

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Answered
Create "n" non-lineal equations in a loop and solved by Fsolve
n=; pi=; p0=; pn=; Ag=; k1=; k2=; k3=; k4=; factor=(p0-pn)/n; for i=1:n-1 x0(i)=p0-factor*i; end x0(n)=0; ...

2 years ago | 0

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Answered
Boundary conditions in pdepe for 1D parabolic velocity profile
The problem set up below is rho*cp*u_z*dT/dz = 1/r * d/dr (r*k*dT/dr) + Q T(z=0,r) = -40 dT/dr = 0 at r = 0 -k*dT/dr = h*(T-...

2 years ago | 0

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Error using fmincon and integral: taking integral variable as an array while performing computation
[q] = optimizeParameters();% Call optimizeParameters to define the objective function q options = optimset('PlotFcns', @optimpl...

2 years ago | 0

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Answered
Using Computational Fluid Dynamics CFD in Matlab
Are you sure that these problems are really meant to be solved with "full CFD" ? MATLAB does not have a CFD tool - you will hav...

2 years ago | 1

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Three y axis with one x axis
https://uk.mathworks.com/matlabcentral/answers/459385-multiple-y-axes-on-single-x-axis

2 years ago | 0

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Can not solve system of differential equations with ode45 taking into account continuity equation
Where do you specify the equations for p1L and p1R ? In your vector of time derivatives [dPdt(t, y(3)); dCdt1(t, y(4), y(1)); ...

2 years ago | 0

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Error: using fmincon: FMINCON requires all values returned by functions to be of data type double.
As you can see above, your function returns a symbolic NaN, but it must return a numerical defined value. To change the output ...

2 years ago | 0

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Answered
Difficulties with symbolically integrating Paris law equation
% Numerically DEL_SIG = 180e6; a = 0.1e-3; ac = 28.6e-3; A = 4e-13; expression = @(x)1./(A*DEL_SIG^4*pi^2*x.^2); N = inte...

2 years ago | 0

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Answered
triple nested integral with error "Arrays have incompatible sizes for this operation."
Please supply an executable code in order to test your code and reproduce the error. Usually, adding 'ArrayValued',true as an o...

2 years ago | 0

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Nested integrals spends quiet different time to calculate for different input values
Check whether the computations are reliable because of the big span of integration. mu1 = 100; sigma1 = 10; mu2 = 200; sigm...

2 years ago | 0

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Could anyone help me with my matlab bvp4c program?
The order of your functions in the dydy function handle is wrong. It should work now. %I am a Researcher, my problem is i t...

2 years ago | 1

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Answered
How can I find the troughs of something without using the function findpeaks?
Use the "diff" function on the array "flow". A peak occurs between flow(i) and flow(i+2) if diff(i) > 0, but diff(i+1) < 0 (m...

2 years ago | 0

Answered
Error Using Optimization with Integer Variables and Non-linear Constraints
Replace norm_h=optimvar('norm_h','Type','integer'); prob = optimproblem('ObjectiveSense','minimize'); prob.Constraints.cons1 ...

2 years ago | 0

Answered
A naive question regarding MATLABs definition of parabolic/elliptical PDEs (pdepe)
https://en.wikipedia.org/wiki/Elliptic_partial_differential_equation Second-order linear partial differential equations (PDEs) ...

2 years ago | 0

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Answered
How to find the point that resides on a contour that is closest to a known point?
format long Z = peaks(50)/10; surf(Z) obj = @(x,y)(x-16.35)^2+(y-0.05)^2; nonlcon = @(z)deal([],interp2(0:49,0:49,Z,z(1),z(2...

2 years ago | 1

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The standard implementation of ldl factorization in Matlab does not work correctly
From the documentation: [L,D] = ldl(A) factorizes full matrix A into a permuted lower triangular matrix L and a block ...

2 years ago | 0

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