/usr/include/SurgSim/Math/OdeSolverEulerExplicitModified.h is in libopensurgsim-dev 0.7.0-5.
This file is owned by root:root, with mode 0o644.
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// Copyright 2013, SimQuest Solutions Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef SURGSIM_MATH_ODESOLVEREULEREXPLICITMODIFIED_H
#define SURGSIM_MATH_ODESOLVEREULEREXPLICITMODIFIED_H
#include "SurgSim/Math/OdeSolver.h"
namespace SurgSim
{
namespace Math
{
/// Modified Euler Explicit ode solver solves the following \f$2^{nd}\f$ order ode
/// \f$M(x(t), v(t)).a(t) = f(t, x(t), v(t))\f$.
/// This ode is solved as an ode of order 1 by defining the state vector
/// \f$y = \left(\begin{array}{c}x\\v\end{array}\right)\f$:
/// \f[
/// y' = \left(\begin{array}{c} x' \\ v' \end{array}\right) =
/// \left(\begin{array}{c} v \\ M(x, v)^{-1}.f(t,x, v) \end{array}\right) =
/// f(t, y)
/// \f]
/// After integrating this equation, we get:
/// \f[ y(t+dt) - y(t) = \int_t^{t+dt} f(t,y) dt \f]
/// \note The modified Euler explicit is the same as Euler explicit, but simply using the newly calculated velocity
/// to update the position with instead of using the velocity from the previous time-step.
/// \note This makes this solver explicit on the velocity and implicit on the position, it improves the stability
/// of the method compare to the Euler explicit but is still an explicit method.
/// \note The numerical integration scheme becomes:
/// \f[
/// \left\{
/// \begin{array}{ccccl}
/// x(t+dt) &=& x(t) &+& dt.v(t+dt)
/// \\ v(t+dt) &=& v(t) &+& dt.a(t)
/// \end{array}
/// \right.
/// \f]
/// \sa OdeSolverEulerExplicit
class OdeSolverEulerExplicitModified : public OdeSolver
{
public:
/// Constructor
/// \param equation The ode equation to be solved
explicit OdeSolverEulerExplicitModified(OdeEquation* equation);
void solve(double dt, const OdeState& currentState, OdeState* newState, bool computeCompliance = true) override;
protected:
void assembleLinearSystem(double dt, const OdeState& state, const OdeState& newState,
bool computeRHS = true) override;
};
}; // namespace Math
}; // namespace SurgSim
#endif // SURGSIM_MATH_ODESOLVEREULEREXPLICITMODIFIED_H
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