Hi,
Just complemented another point. You might also need to Gather and Scatter
the acceleration and Lagrange multipliers if you want to recover the system
state exactly as the snapshot investigated.
Something like:
auto state_der2 =
chrono_types::make_shared<ChStateDelta>(system.GetNumCoordsVelLevel(),
&system);
system.StateGatherAcceleration(*state_der2);
auto state_L =
chrono_types::make_shared<ChVectorDynamic<>>(system.GetNumConstraints());
system.StateGatherReactions(*state_L);
and similarly for the Scattering (i.e. loading back into ChSystem).
The complete state of a system includes: X (position and orientation), V
(velocity), A (acceleration), T (time), L( Lagrange multipliers).
Good luck.
Chao PENG.
在2024年6月20日星期四 UTC+2 23:24:31<[email protected]> 写道：
BTW, if you just want to load/save the state of the system, without the
model itself, you can come up with some easier yet not complete, solution
of using ChSystem::StateGather and ChSystem::StateScatter.
Something like:
auto state =
chrono_types::make_shared<ChState>(system.GetNumCoordsPosLevel(), &system);
auto state_der =
chrono_types::make_shared<ChStateDelta>(system.GetNumCoordsVelLevel(),
&system);
double time;
system.StateGather(*state , *state_der, time_dummy);
and similarly for the Scattering (i.e. loading back into ChSystem)
Please notice however that you have to make sure that the model is exactly
the same and also that can be additional relevant variables (e.g. some
variable in the timesteppers) that is not retrieved in this way thus making
a slight difference when you load back the state.
Il giorno giovedì 20 giugno 2024 alle 23:18:46 UTC+2 Dario Mangoni ha
scritto:
Hi,
yes there is.
You may find more references by searching for the "archive" keyword instead
of serialization.
*demo_CH_archive
<https://github.com/projectchrono/chrono/blob/main/src/demos/core/demo_CH_archive.cpp>*is
a starting point, but it's probably showing many more features that just
simply a Chrono system serialization.
*utest_CH_archive
<https://github.com/projectchrono/chrono/blob/main/src/tests/unit_tests/core/utest_CH_archive.cpp>*is
another source of information, while it's meant for testing.
In general you can import|export to JSON, XML and binary format.
In general, for a whole ChSystem, you can simply do something like.
{
ChSystemNSC system;
ADD THINGS TO YOUR SYSTEM
std::ofstream mfileo("ChArchiveJSON_Pendulum.json");
ChArchiveOutJSON archive_out(mfileo);
archive_out << CHNVP(system);
}
std::ifstream mfilei("ChArchiveJSON_Pendulum.json");
ChArchiveInJSON archive_in(mfilei);
ChSystemNSC system;
archive_in >> CHNVP(system);
Please mind that not all the classes are enabled to serialization (e.g.
ChVisualShapeFEA are not).
You may be able to check which are enabled by checking the relative
ArchiveIn|ArchiveOut methods for each class.
Il giorno giovedì 20 giugno 2024 alle 20:00:49 UTC+2 [email protected] ha
scritto:
Is there any way to serialize Chrono::Systems so that the system state is
recoverable from disk? I'd like to be able to save the state of the system
for debugging at a later date.
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