## CppCon 2024, Aurora, CO, USA, September 15-20, 2024 ## Real-Time Circuit Simulation with Wave Digital Filters in C++ 

ELIAS FARHAN 20 24 September 15 - 20 ## Summary • Introduction • Why is it hard? - Why deterministic simulation? • What is rollback? • Implementation details • Debugging • Improvements  Client 2 Local Game State ## Deterministic simulation Initial state GameSystems::Tick() on Nintendo Switch ARM Cortex-A57 ![Image](/upload Desktop PC Intel Core i7-8700K New state New state With a deterministic simulation, we mostly need to send player inputs! ## Deterministic lock-step For example in Age of Empires. From the article

will be towards achieving data determinism via: • Deterministic execution $ ^{2} $ will always run computations in the same order. - Deterministic communication $ ^{2} $ is when, for a message going communication is guaranteed to be complete always before or always after B executes. Also, to be data deterministic, any computation should not use system interfaces or other library calls (other than ROS messages) Sending/receiving a message b. A timer that expired 6. Test simulation scenarios in the CI ## Determinism and challenges with ROS Deterministic resource usage and runtime is necessary for a safety-critical

Less likely, but much more seriously, results might be different because the chaincode is non-deterministic. Non-determinism is the enemy of chaincodes and ledgers and if it occurs it indicates a serious obviously, be applied to ledgers. An individual peer cannot know that their transaction result is non-deterministic – transaction responses must be gathered together for comparison before non-determinism can be The application channel encodes a copy of the orderer orgs and consensus options to allow for deterministic updating of these parameters, so the same orderer section from the orderer system channel configuration

Less likely, but much more seriously, results might be different because the chaincode is non-deterministic. Non-determinism is the enemy of chaincodes and ledgers and if it occurs it indicates a serious obviously, be applied to ledgers. An individual peer cannot know that their transaction result is non-deterministic – transaction responses must be gathered together for comparison before non-determinism can be The application channel encodes a copy of the orderer orgs and consensus options to allow for deterministic updating of these parameters, so the same Orderer section from the orderer system channel configuration

contracts executing in a blockchain that operates with the order-execute architecture must be deterministic; otherwise, consensus might never be reached. To address the non-determinism issue, many platforms contracts be written in a non-standard, or domain-specific language (such as Solidity) so that non-deterministic operations can be eliminated. This hinders wide-spread adoption because it requires developers Endorsing peer – defined by policy as specific nodes that execute smart contract transactions in simulation and return a proposal response (endorsement) to the client application. • Committing peer – validates

contracts executing in a blockchain that operates with the order-execute architecture must be deterministic; otherwise, consensus might never be reached. To address the non-determinism issue, many platforms domain-specific language (such as Solidity [https://solidity.readthedocs.io/en/v0.4.23/]) so that non-deterministic operations can be eliminated. This hinders wide-spread adoption because it requires developers Endorsing.peer – defined by policy as specific nodes that execute smart contract transactions in simulation and return a proposal response (endorsement) to the client application. • Committing.peer – validates

contracts executing in a blockchain that operates with the order-execute architecture must be deterministic; otherwise, consensus might never be reached. To address the non-determinism issue, many platforms contracts be written in a non-standard, or domain-specific language (such as Solidity) so that non-deterministic operations can be eliminated. This hinders wide-spread adoption because it requires developers Less likely, but much more seriously, results might be different because the chaincode is non-deterministic. Non-determinism is the enemy of chaincodes and ledgers and if it occurs it indicates a serious

contracts executing in a blockchain that operates with the order-execute architecture must be deterministic; otherwise, consensus might never be reached. To address the non-determinism issue, many platforms domain-specific language (such as Solidity [https://solidity.readthedocs.io/en/v0.4.23/]) so that non-deterministic operations can be eliminated. This hinders wide-spread adoption because it requires developers Less likely, but much more seriously, results might be different because the chaincode is non-deterministic. Non-determinism is the enemy of chaincodes and ledgers and if it occurs it indicates a serious

contracts executing in a blockchain that operates with the order-execute architecture must be deterministic; otherwise, consensus might never be reached. To address the non-determinism issue, many platforms contracts be written in a non-standard, or domain-specific language (such as Solidity) so that non-deterministic operations can be eliminated. This hinders wide-spread adoption because it requires developers Less likely, but much more seriously, results might be different because the chaincode is non-deterministic. Non-determinism is the enemy of chaincodes and ledgers and if it occurs it indicates a serious