public static void Progress_rk2(LeapFrogState state, double dt)
{
var N = state.N;
var old_pos = state.position.Select(p => new Vector3(p)).ToList();
var a0 = state.EulerState_ComputeAccelerationVectorDirect();
var half_vel = new Vector3[N];
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
half_vel[i] = state.velocity[i] + a0[i] * 0.5 * dt;
state.position[i] += state.velocity[i] * 0.5 * dt;
});
var a1 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
state.velocity[i] += a1[i] * dt;
state.position[i] = old_pos[i] + half_vel[i] * dt;
});
state.currentTime += dt;
}
public static void Progress_rk2(LeapFrogState state, double dt)
{
var N = state.N;
var old_pos = state.position.Select(p => new Vector3(p)).ToList();
var a0 = state.EulerState_ComputeAccelerationVectorDirect();
var half_vel = new Vector3[N];
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
half_vel[i] = state.velocity[i] + a0[i] * 0.5 * dt;
state.position[i] += state.velocity[i] * 0.5 * dt;
});
var a1 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
state.velocity[i] += a1[i] * dt;
state.position[i] = old_pos[i] + half_vel[i] * dt;
});
state.currentTime += dt;
}
public static void Progress_rk4(LeapFrogState state, double dt)
{
var po = new ParallelOptions {
MaxDegreeOfParallelism = System.Environment.ProcessorCount
};
var N = state.N;
var old_pos = state.position.AsParallel().Select(oldpos => new Vector3(oldpos)).ToList();
var a0 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, po, i =>
//for (int i = 0; i < N; i++)
{
state.position[i] = old_pos[i]
+ state.velocity[i] * 0.5 * dt
+ a0[i] * 0.125 * dt * dt;
});
var a1 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, po, i =>
//for (int i = 0; i < N; i++)
{
state.position[i] = old_pos[i]
+ state.velocity[i] * dt
+ a0[i] * 0.5 * dt * dt;
});
var a2 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, po, i =>
//for (int i = 0; i < N; i++)
{
state.position[i] = old_pos[i]
+ state.velocity[i] * dt
+ (a0[i] + a1[i] * 2.0) * (1.0 / 6.0) * dt * dt;
state.velocity[i] += (a0[i] + a1[i] * 4.0 + a2[i]) * (1.0 / 6.0) * dt;
});
state.currentTime += dt;
}
public static void Progress_LeapFrog(LeapFrogState lfState, double dt)
{
var N = lfState.N;
var deltaTimeHalf = dt * 0.5;
Vector3[] acceleration1;
if (lfState.currentTime == lfState.m_timeOfAccelerationCalculated && lfState.m_accelerations != null) // && length matches, in case we merge or split particles
{
acceleration1 = lfState.m_accelerations;
}
else
{
acceleration1 = lfState.EulerState_ComputeAccelerationVectorDirect();
}
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
lfState.velocity[i] += acceleration1[i] * deltaTimeHalf;
lfState.position[i] += lfState.velocity[i] * dt;
});
var acceleration2 = lfState.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
lfState.velocity[i] += acceleration2[i] * deltaTimeHalf;
});
lfState.currentTime += dt;
lfState.m_timeOfAccelerationCalculated = lfState.currentTime;
lfState.m_accelerations = acceleration2;
}
public static void Progress_LeapFrog(LeapFrogState lfState, double dt)
{
var N = lfState.N;
var deltaTimeHalf = dt * 0.5;
Vector3[] acceleration1;
if (lfState.currentTime == lfState.m_timeOfAccelerationCalculated && lfState.m_accelerations != null) // && length matches, in case we merge or split particles
acceleration1 = lfState.m_accelerations;
else
acceleration1 = lfState.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
lfState.velocity[i] += acceleration1[i] * deltaTimeHalf;
lfState.position[i] += lfState.velocity[i] * dt;
});
var acceleration2 = lfState.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, i =>
//for (int i = 0; i < N; i++)
{
lfState.velocity[i] += acceleration2[i] * deltaTimeHalf;
});
lfState.currentTime += dt;
lfState.m_timeOfAccelerationCalculated = lfState.currentTime;
lfState.m_accelerations = acceleration2;
}
public static void Progress_rk4(LeapFrogState state, double dt)
{
var po = new ParallelOptions { MaxDegreeOfParallelism = System.Environment.ProcessorCount };
var N = state.N;
var old_pos = state.position.AsParallel().Select(oldpos => new Vector3(oldpos)).ToList();
var a0 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, po, i =>
//for (int i = 0; i < N; i++)
{
state.position[i] = old_pos[i]
+ state.velocity[i] * 0.5 * dt
+ a0[i] * 0.125 * dt * dt;
});
var a1 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, po, i =>
//for (int i = 0; i < N; i++)
{
state.position[i] = old_pos[i]
+ state.velocity[i] * dt
+ a0[i] * 0.5 * dt * dt;
});
var a2 = state.EulerState_ComputeAccelerationVectorDirect();
Parallel.For(0, N, po, i =>
//for (int i = 0; i < N; i++)
{
state.position[i] = old_pos[i]
+ state.velocity[i] * dt
+ (a0[i] + a1[i] * 2.0) * (1.0 / 6.0) * dt * dt;
state.velocity[i] += (a0[i] + a1[i] * 4.0 + a2[i]) * (1.0 / 6.0) * dt;
});
state.currentTime += dt;
}