// modifies this->a and uses this->delta_a
void ChangeAccel(int d, float step)
{
// only the not clamped variables, including the current variable, can have an acceleration unequal zero
SIMDProcessor.MulAdd(a.ToArray() + numClamped, step, delta_a.ToArray() + numClamped, d - numClamped + 1);
}
// modifies this->f and uses this->delta_f
void ChangeForce(int d, float step)
{
// only the clamped variables and current variable have a force delta unequal zero
SIMDProcessor.MulAdd(f.ToArray(), step, delta_f.ToArray(), numClamped);
f[d] += step * delta_f[d];
}