Community Profile # e_frog

Last seen: 2 days ago Active since 2020

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Question

How to group specific values i several vectors following a condition?
Hi, I am struggeling to find a method to extract values that comply with a specific condition from a vector. The input is a ra...

3 days ago | 1 answer | 0

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Question

How does MultiStart generate startpoints? Why is StartPointsToRun even necessary?
As I understand from this "MultiStart uses uniformly distributed start points within bounds, or user-supplied start points." Mul...

7 months ago | 0 answers | 0

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Solved

Times 2 - START HERE
Try out this test problem first. Given the variable x as your input, multiply it by two and put the result in y. Examples:...

7 months ago

Question

Fmincon / Multistart: Local minimum found, but one nonlinear constraint is violated
Hi, i am trying to find an optimal point with multistart / fmincon. Matlab finds a local minima, for which the following messag...

7 months ago | 1 answer | 1

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Question

GlobalSearch - Does a non-default number of trial points stop the effect of the maxTime option?
Hi, I am using GlobalSearch() to find an optimum of a solution of odes in fmincon. The functions in fmincon have many input var...

9 months ago | 0 answers | 0

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Question

Vicious Circle Problem: How to solve ODEs with variables that are based on the solutions of the ODEs?
Assuming I have the following system of ODEs: dSdt = [S(2); L*S(1)+R*(S(1)-S(3)); S(4); -g*(S(1)-S(3...

9 months ago | 2 answers | 0

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Question

How to know if a minimum found with Global Search is actually the Global minimum?
I try to find a global minimum with fmincon() in a GlobalSearch. I gave it a maximum runtime of 30 minutes. The solver ended lon...

9 months ago | 1 answer | 0

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Question

fmincon, nonlcon, ode45 - objective output in nonlinear constraint
I want to use the output of the objective function in the nonlinear constraint function. My goal is to constrain a solution of a...

10 months ago | 1 answer | 0

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how can I solve ODE without initial condition?
Try formulating the problem as a boundary value problem and solving it with bvp4c or bvp5c. See also: Boundary Value Problems...

11 months ago | 0

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Question

fmincon, nonlcon - too many input arguments
Hi i am trying to minimize some output of a system of 2 ODEs that also are bound by a nonlinear constraint. Unfortunately I cant...

11 months ago | 1 answer | 0

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Question

Second derivative of solution from ode45
I have a system of 2 second order ODEs, which i converted to a system of fist order ODEs, which ode45 (or ode15s) needs as an in...

12 months ago | 1 answer | 0

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Question

BVP for system of 2 second order ODEs
I have a system of two second order ODEs that I want to calculate using bvp4c. I have some problems transforming the second orde...

12 months ago | 1 answer | 0

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Question

dsolve very slow for system of 2 second order ODEs
Hi, I have to solve a system of 2 second order ODEs with 4 initial conditions. They are also coupled (state variables: and ). ...

12 months ago | 1 answer | 0

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Question

How to solve an ODE with ode45 in a parfor loop?
I have the following code: function [t,S] = solve_ode(fg_vars,tspan) inital_conds = [0 0]; t = zeros(65,1); ...

12 months ago | 1 answer | 0