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已回答
error lsqcurvefit for integrate function
Replace % Define the model function (vectorized for efficiency) function y = model(theta, x) k0 = theta(1); E0 = theta(2...
error lsqcurvefit for integrate function
Replace % Define the model function (vectorized for efficiency) function y = model(theta, x) k0 = theta(1); E0 = theta(2...
2 hours 前 | 0
已回答
How to set Drichlet and Neumann boundary conditions for a set of ode in BVP solver
Is there a possibility that I can set three boundaries (mix between Drichlet and Neumann boundary) for a set of two ODE's? No....
How to set Drichlet and Neumann boundary conditions for a set of ode in BVP solver
Is there a possibility that I can set three boundaries (mix between Drichlet and Neumann boundary) for a set of two ODE's? No....
3 hours 前 | 0
已回答
Trying to determine roots of this polynomial (Det)
k = [1750 -750 0; -750 1250 -500; 0 -500 500]; m = [75 0 0; 0 75 0; 0 0 50]; eig(k,m)
Trying to determine roots of this polynomial (Det)
k = [1750 -750 0; -750 1250 -500; 0 -500 500]; m = [75 0 0; 0 75 0; 0 0 50]; eig(k,m)
4 hours 前 | 0
已回答
Civil engineering coding problem ( I dont know where the problem in my code is and how to solve it, thanks in advance )
"coord" has only three rows, but you try to access coord(4,1) and coord(4,2) which do not exist (see above).
Civil engineering coding problem ( I dont know where the problem in my code is and how to solve it, thanks in advance )
"coord" has only three rows, but you try to access coord(4,1) and coord(4,2) which do not exist (see above).
5 hours 前 | 0
已回答
Why I am getting this error message? How to fix it?
Maybe you mean this function: function v = vec(m) %Helper function to turn a matrix of any size into a column vector using (:)...
Why I am getting this error message? How to fix it?
Maybe you mean this function: function v = vec(m) %Helper function to turn a matrix of any size into a column vector using (:)...
5 hours 前 | 1
已回答
How to draw a three-dimensional function image corresponding to the analytic expression of a given piecewise function image
f = @(x,y)(4*y-4*x.*y-2*y.^2).*(y<x).*(x+y<1)+2*(1-x).^2.*(y<x).*(x+y>=1)+(4*y-4*y.^2-2*x.^2).*(y>=x).*(x+y<1)+(2-4*x+4*x.*y-2*y...
How to draw a three-dimensional function image corresponding to the analytic expression of a given piecewise function image
f = @(x,y)(4*y-4*x.*y-2*y.^2).*(y<x).*(x+y<1)+2*(1-x).^2.*(y<x).*(x+y>=1)+(4*y-4*y.^2-2*x.^2).*(y>=x).*(x+y<1)+(2-4*x+4*x.*y-2*y...
6 hours 前 | 0
| 已接受
已回答
Generalized Orr Sommerfield error returned in Eigs Function
I suggest you comment out the command W0 = @(x) lambertw(0,x); like %W0 = @(x) lambertw(0,x); include a function for W0 as ...
Generalized Orr Sommerfield error returned in Eigs Function
I suggest you comment out the command W0 = @(x) lambertw(0,x); like %W0 = @(x) lambertw(0,x); include a function for W0 as ...
1 day 前 | 0
已回答
How can i solve this problem' when i am running, this message appears: Failure in initial objective function evaluation. FMINUNC cannot continue.
Call your function in which you define the sum of differences squared between real and modelled data for the initial values of y...
How can i solve this problem' when i am running, this message appears: Failure in initial objective function evaluation. FMINUNC cannot continue.
Call your function in which you define the sum of differences squared between real and modelled data for the initial values of y...
1 day 前 | 0
已回答
hypergeom function, no output
The hypergeometric function has convergence criteria: Converges if p ≤ q and |z| < ∞. Converges if p = q + 1 and |z| < 1. For ...
hypergeom function, no output
The hypergeometric function has convergence criteria: Converges if p ≤ q and |z| < ∞. Converges if p = q + 1 and |z| < 1. For ...
1 day 前 | 1
| 已接受
已回答
How to plot a simple wave equation using method of lines?
n = 100; m = 100; tf = 1; dx = 1/n; x = linspace(0,1,n+1)'; tspan = linspace(0,tf,m+1); y0 = [sin(2*pi*x);zeros(n+1,1)]; %[t...
How to plot a simple wave equation using method of lines?
n = 100; m = 100; tf = 1; dx = 1/n; x = linspace(0,1,n+1)'; tspan = linspace(0,tf,m+1); y0 = [sin(2*pi*x);zeros(n+1,1)]; %[t...
2 days 前 | 0
| 已接受
已回答
Analytical solution of 1-D transient heat transfer
I'd compare with the solution from "pdepe": m = 1; Ri = 0.05; nd = 20; r = linspace(0,Ri,nd); t = [0 100 600 1800 3600 5000...
Analytical solution of 1-D transient heat transfer
I'd compare with the solution from "pdepe": m = 1; Ri = 0.05; nd = 20; r = linspace(0,Ri,nd); t = [0 100 600 1800 3600 5000...
3 days 前 | 0
已回答
Solve Nonlinear ODE Symbolically
This is a nonlinear system of ODEs. An analytical solution with symbolic math is not possible. The only way to solve it is nume...
Solve Nonlinear ODE Symbolically
This is a nonlinear system of ODEs. An analytical solution with symbolic math is not possible. The only way to solve it is nume...
4 days 前 | 1
| 已接受
已回答
Triple intergral for the array valued function
N = cell(2,3); N{1,1} =@(x,y,z) x.^2+y.^2+z.^2; N{1,2} =@(x,y,z) x.^2+y.^2+z.^2; N{1,3} =@(x,y,z) x.^2; N{2,1} =@(x,y,z) y....
Triple intergral for the array valued function
N = cell(2,3); N{1,1} =@(x,y,z) x.^2+y.^2+z.^2; N{1,2} =@(x,y,z) x.^2+y.^2+z.^2; N{1,3} =@(x,y,z) x.^2; N{2,1} =@(x,y,z) y....
4 days 前 | 0
已回答
does "generalized Neumann" boundary condition include actual Neumann boundary condition?
Is there maybe a workaround (like change of variables) to solve these problems? No. All Neumann boundary conditions are related...
does "generalized Neumann" boundary condition include actual Neumann boundary condition?
Is there maybe a workaround (like change of variables) to solve these problems? No. All Neumann boundary conditions are related...
4 days 前 | 0
| 已接受
已回答
Graphing 1D Diffusion in 2 Compartments - Possible Issue with ODE solver
In my opinion, you have the following conditions at the interface x = h_D: (1) D_D*dC_D/dx = D_R*dC_R/dx (2) C_R = phi*C_D (or...
Graphing 1D Diffusion in 2 Compartments - Possible Issue with ODE solver
In my opinion, you have the following conditions at the interface x = h_D: (1) D_D*dC_D/dx = D_R*dC_R/dx (2) C_R = phi*C_D (or...
5 days 前 | 0
已回答
I want to optimize an ODE system of equations with constraints
I ran your code with k in the order of 0.1,1 and 10, but it seems the k-values have amost no influence on the result of the inte...
I want to optimize an ODE system of equations with constraints
I ran your code with k in the order of 0.1,1 and 10, but it seems the k-values have amost no influence on the result of the inte...
5 days 前 | 0
| 已接受
已回答
Solving edge-value problems with unknown intervals
Define a dimensionless variable x' = x/l1 and transform your equation to the form dY/dx' = ... which has to be solved in [0 1]. ...
Solving edge-value problems with unknown intervals
Define a dimensionless variable x' = x/l1 and transform your equation to the form dY/dx' = ... which has to be solved in [0 1]. ...
5 days 前 | 1
已回答
How to calculate a composite triple integral with exponential function?
Setting l, r and s to zero will cause problems because you divide by these variables. But also changing integral2(@(s,l)array...
How to calculate a composite triple integral with exponential function?
Setting l, r and s to zero will cause problems because you divide by these variables. But also changing integral2(@(s,l)array...
5 days 前 | 0
| 已接受
已回答
Error using lsqncommon Lower and upper bounds not supported with complex-valued initial function or Jacobian evaluation.
If you use "fmincon" and (f(x,xdata)-ydata)' * (f(x,xdata)-ydata) as objective function, complex numbers don't matter because th...
Error using lsqncommon Lower and upper bounds not supported with complex-valued initial function or Jacobian evaluation.
If you use "fmincon" and (f(x,xdata)-ydata)' * (f(x,xdata)-ydata) as objective function, complex numbers don't matter because th...
6 days 前 | 0
| 已接受
已回答
Solve a complex differential equations system
The main problem with your equations is that they involve a term that has to be evaluated at a boundary point. Otherwise, you co...
Solve a complex differential equations system
The main problem with your equations is that they involve a term that has to be evaluated at a boundary point. Otherwise, you co...
6 days 前 | 0
已回答
an ode with arguements
You have to define your vector of solution variables as y(1) = f, y(2) = f', y(3) = f'', y(4) = T, y(5) = T' and your function...
an ode with arguements
You have to define your vector of solution variables as y(1) = f, y(2) = f', y(3) = f'', y(4) = T, y(5) = T' and your function...
6 days 前 | 0
已回答
How to invert a square matrix using Gaussian elimination
The newton update is x_(n+1) = x_n - Df^(-1)*f, not x_(n+1) = x_n + Df^(-1)*f. But you should not explicitly compute the ...
How to invert a square matrix using Gaussian elimination
The newton update is x_(n+1) = x_n - Df^(-1)*f, not x_(n+1) = x_n + Df^(-1)*f. But you should not explicitly compute the ...
7 days 前 | 1
已回答
Find Eigenvalues of ODE45 Solution MATLAB
Your system reads z1'= z2 z2' = ( F-(c1+c2)*z2-( ((k1*gamma1+k2*gamma2)*z1^2+k1+k2)*z1+(-k2*gamma2*z1^2-k2)*z3 ) )/m1 z3' = z...
Find Eigenvalues of ODE45 Solution MATLAB
Your system reads z1'= z2 z2' = ( F-(c1+c2)*z2-( ((k1*gamma1+k2*gamma2)*z1^2+k1+k2)*z1+(-k2*gamma2*z1^2-k2)*z3 ) )/m1 z3' = z...
7 days 前 | 1
| 已接受
已回答
How to get an expression for a Hypergeometric function with symbiotic variable
MATLAB is not able to find the Inverse Laplace transform of such a complicated function as an analytic expression.
How to get an expression for a Hypergeometric function with symbiotic variable
MATLAB is not able to find the Inverse Laplace transform of such a complicated function as an analytic expression.
7 days 前 | 0
| 已接受
已回答
can someone please help me coding this saturation equations in matlab
m, umax and u have to be defined previously. psi = zeros(m,1); idx = abs(u) > umax; psi(idx) = sign(u(idx)).*min(abs(u(idx)),...
can someone please help me coding this saturation equations in matlab
m, umax and u have to be defined previously. psi = zeros(m,1); idx = abs(u) > umax; psi(idx) = sign(u(idx)).*min(abs(u(idx)),...
7 days 前 | 0
| 已接受
已回答
variable problem of GA
t=[0.015 0.01 0.009 0.012 0.016 0.014 0 0]; w=[0.005 0.004 0.003 0.004 0.006 0.004 0 0]; options = optimoptions( ... 'ga'...
variable problem of GA
t=[0.015 0.01 0.009 0.012 0.016 0.014 0 0]; w=[0.005 0.004 0.003 0.004 0.006 0.004 0 0]; options = optimoptions( ... 'ga'...
7 days 前 | 0
| 已接受
已回答
fmincon solution does not differ from initial guess if I provide gradient
Use SpecifyObjectiveGradient Gradient for the objective function defined by the user. See the description of fun to see how to...
fmincon solution does not differ from initial guess if I provide gradient
Use SpecifyObjectiveGradient Gradient for the objective function defined by the user. See the description of fun to see how to...
7 days 前 | 0
已回答
When using integral function to calculate MeijerG function, Matlab will get stuck.
meijerG has a division by 0 at SNR = 0. If you are sure the integral exists at SNR = 0, start with a small value > 0, e.g. aver...
When using integral function to calculate MeijerG function, Matlab will get stuck.
meijerG has a division by 0 at SNR = 0. If you are sure the integral exists at SNR = 0, start with a small value > 0, e.g. aver...
8 days 前 | 0
| 已接受
已回答
Set answers of first BVP as new boundary condition for second BVP
"value_at_1" is defined in the script part of your code, but it's not automatically visible in the functions you define. Either ...
Set answers of first BVP as new boundary condition for second BVP
"value_at_1" is defined in the script part of your code, but it's not automatically visible in the functions you define. Either ...
8 days 前 | 0
已回答
lsqcurvefit can't get to the right values
It seems that a variation of your parameters has almost no effect on epsilon_equation. This makes lsqcurvefit assume it cannot m...
lsqcurvefit can't get to the right values
It seems that a variation of your parameters has almost no effect on epsilon_equation. This makes lsqcurvefit assume it cannot m...
9 days 前 | 0
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