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Plotting the outcome of a 3D fit
x = 0:0.1:1; y = -1:0.1:1; [X,Y] = meshgrid(x,y); Z = X.^2+Y.^2+0.1*(-1+2*rand(size(X))); [Xout,Yout,Zout] = prepareSurfaceD...

3年弱前 | 0

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I have given matrix Q and function to solve ode45 .here 'x' and 'f' is a column 20*1 vector. xprime is a derivative of x.please help me the code to co
x is 20x1, f is 38x1 ... -> Dimension error.

3年弱前 | 1

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Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parenthe
Works for me (see above).

3年弱前 | 0

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Goodness of fit for weibull distribution
https://www.spcforexcel.com/knowledge/basic-statistics/deciding-which-distribution-fits-your-data-best https://stats.stackexcha...

3年弱前 | 0

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How can I generate a vector like this 1,2,2,3,3,3,4,4,4,4 by using for loop?
Start with y = [] and in each step of the for-loop running from 1 to n, concatenate y and i*ones(1,i).

3年弱前 | 0

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Hello, I have problem with odeToVectorField in ODE second order system of equations.
dydt = fun(0.1,ones(12,1)).' function dydt = fun(t,y) g= 9.81; m= 0.468; Ix= 4.856e-3; Iy= 4.856e-3; Iz= 8.801e...

3年弱前 | 0

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Why am i getting the error 'The first input to exist must be a string scalar or character vector' while solving 4 ode using ode45 solver ??
ode45 is a numerical integrator. It doesn't accept symbolic inputs. b = deg2rad(45); tspan = [0 pi]; y0 = [0.10 3.14e-06 1.4...

3年弱前 | 0

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How to find the intersection values?
format long d1 = 0.4;d2 = 0.6;d = d1 + d2; n1 = sqrt(12);n2 = 1; D1 = @(lambda)(2*pi*n1*d1)./lambda;D2 = @(lambda)(2*pi*n2*d2...

3年弱前 | 0

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2nd order differential equation with two 1st order differential equations boundary condtions
This is the code for the equation and boundary conditions you posted: xmesh = 6:0.005:6.5; solinit = bvpinit(xmesh, [6.55 0.57...

3年弱前 | 0

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in the below mentioned code, i get an error in finding some elements (not in all) : 0×1 empty double column vector
k = find(abs(x-0.3)==min(abs(x-0.3)))

3年弱前 | 0

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What can I do if Matlab never stops calculating a system of equations?
I'd suggest you don't use the symbolic toolbox for your problem, but to define an optimization problem: min: any function you l...

3年弱前 | 0

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Solve the integral in the point where the function is singular
I'd suggest syms x func1_symb=sqrt(0.025)/(8*sqrt(pi*(x-x_approach(1)))); value_integral = 0.0; for i = 1:numel(x_approach)-...

3年弱前 | 0

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Solving a problem with the Shooting Newton Method in Matlab
sol = fsolve(@fun,23,optimset('TolFun',1e-12,'TolX',1e-12)); fun(sol) [X,Y] = ode_solver(sol); figure(1) hold on plot(X,Y(:...

3年弱前 | 0

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Doubt in a program
Why ? In order to plot a time-location curve after the while-loop, the intermediate results for time and location are saved in ...

約3年前 | 0

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2D diffusion equation for a laser heat source
qdot is 1x51, T(Sy,Sx) is a scalar. Thus Tn(Sy,Sx)=Tn(Sy,Sx)+dt*q_dot/rho/cp; tries to assign an array to a scalar which thro...

約3年前 | 0

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yy3 is generating a straight line while it should generate a curve, i don't understand what is wrong!!!
As initial condition for y(7), you set y(7) = 0, and you define the differential equation for y(7) as dy(7)/dx = y(7). The solut...

約3年前 | 0

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Solve non linear equation with vector
x(k1) = 45+dados.mass(k1)*sqrt(-2*log(dados.par(k1))) or x(k1) = 45-dados.mass(k1)*sqrt(-2*log(dados.par(k1)))

約3年前 | 1

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Heat Flow in PDEToolbox: Uniform Heat Flux does not give uniform temperature.
Either you presribe heat flux or convection coefficient and ambient temperature on Face 3. I don't understand how both options c...

約3年前 | 0

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Exponential fitting of data not working
A = load("T_A.mat"); A = A.T_A; A = [linspace(0,83.3,1666).',A]; plot(A(:,1),A(:,2),'o') hold on p0 = [25 1 1]; f = @(p)p(...

約3年前 | 0

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Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 0-by-1.
rand(-1,1) tries to create a matrix of uniformly distributed random variables on [0,1] with dimensions -1 and 1. A negative matr...

約3年前 | 0

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How to calculate empirical cumulative distribution function of a dataset? If I use ecdf function then why the number of datapoints are decreasing? Is there any other formula?
If I use ecdf function then why the number of datapoints (the matrix f1 becomes (1564x1) and x1 becomes(1564x1) matrix) are decr...

約3年前 | 0

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Hello folks, I need help regarding visualization of solutions for a transient thermal analysis done using PDE solver on a 3D geometry.
ad 1) Face 2 is an internal boundary. You don't need to set a boundary condition on it. The internal boundary condition is T_le...

約3年前 | 0

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Nonlinear overdetermined equation systems
By using "lsqnonlin", e.g. sol0 = [0 0 0 0]; sol = lsqnonlin(@fun,sol0) norm(fun(sol)) function res = fun(u); x = u(1);...

約3年前 | 0

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can anyone help me about Error using optim.problemdef.OptimizationProblem/solve Invalid argument at position 2. Value must be finite.
Above your error - written out more clearly so that you as the coder should be able to understand the problem. In nodestr=dec...

約3年前 | 0

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Problem to solve nonlinear Eq. with Newton's Method
i=sqrt(-1); n1=1; n3=1.515; lambda=632.8; %nm alpha0=-deg2rad([50 55 60]); teta1=deg2rad(50); phi0 =deg2rad([75.357 68...

約3年前 | 0

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How to plot two concentric spheres with radius1=1 and radius2 =10 in MATLAB and filled with fluid flow (I have one velocity component only)
lambda=1.5; eta=1; beta1=10;beta2=10; alpha=.00001; eta1=0.0;w=0.1;k=(1/eta.^2).^(0.5); a=1; % w=w2/w1 alpha1=((k.^2+(k....

約3年前 | 1

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How to plot two concentric spheres with radius1=1 and radius2 =10 in MATLAB and filled with fluid flow (I have one velocity component only)
I'm surprised that velocity increases with growing r. Continuity equation should force velocity to decrease. But maybe my parame...

約3年前 | 0

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levenberg-marquardt with linear constraints
x = lsqnonlin(fun,x0,lb,ub,A,b,Aeq,beq,nonlcon) A,b,Aeq,beq define the linear constraints.

約3年前 | 2

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measurement based optimization using fmincon
"fmincon" is not a stochastic, but a deterministic optimizer. You are not allowed to use random inputs for it that change every ...

約3年前 | 0

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Error: Limits of integration must be double or single scalars. While solving equations numerically with symbolic integral limits
I guess this is what you mean. initial_guess = [0.5, 0.1, 2]; % Use fsolve to solve the equation system result = fsolve(@(var...

約3年前 | 1

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