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% pendulum_energy.m
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% MATLAB user function for the vector field: pendulum
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% This file was generated by the program VFGEN (Version:2.4.0)
% Generated on 16-Jul-2008 at 20:17
%
%
function r_ = pendulum_energy(t,x_,p_)
    Pi = pi;
    theta      = x_(1);
    v          = x_(2);
    g          = p_(1);
    b          = p_(2);
    L          = p_(3);
    m          = p_(4);
    r_ = -m*g*L*cos(theta)+1/2*m*v^2*L^2;