Distributed simulation

Abstract

A method and apparatus are presented to facilitate simulation of complex systems on multiple computing devices. Model authors can specify state-related information to be exported for viewing or access by other applications and models. Subsystem models may be written to enable connection with other subsystem models via controlled interfaces, such as by defining state-related information for export and providing for a particular use of data imported from other models to which a subsystem model is connected. In some embodiments, a consistent distributed simulation API enables cross-platform, multi-device simulation of complex systems, wherein the proprietor of each subsystem simulation can keep its implementation secret but accessible to others.

1 . A computer-implemented method for simulating operation of a physical system having a plurality of physical subsystems, comprising:
 simulating a first physical subsystem with a first continuous-time simulation on a first physical computing device;   accepting a request for export of information relating to a number n of state-related variables that characterize the state of the first physical subsystem in said simulating;   sending a first series of state-related messages, each message containing information relating to the value of at least one of the n state-related variables;   simulating a second physical subsystem with a second continuous-time simulation on a second physical computing device;   receiving in said second continuous-time simulation said first series of state-related messages from said first continuous-time simulation without said first series of state-related messages passing through a central communication process;   outputing data representative of a state of the second continuous-time simulation; wherein:
 the first physical subsystem interacts with the second physical subsystem; 
 the at least one state-related variable characterizes at least a portion of the interaction between the first physical subsystem and the second physical subsystem; and 
 the number n is at least two; and 
   sending a third series of state-related numerical values, wherein:
 at least one numerical value in the first series of state-related numerical values contains information relating to the values of a first proper subset of the set containing all n state-related variables; 
 at least one numerical value in the third series of state-related numerical values contains information relating to the values of a second proper subset of the set containing all n state variables, and 
 the second proper subset is different from the first proper subset; 
   
     wherein:
 the messages in the first series of state-related numerical values are sampled at a first rate in simulation time in the first simulation; 
 the numerical values in the third series of state-related numerical values are sampled at a second rate in simulation time in the first simulation; and 
 the first rate and the second rate are not equal. 
 
   
   
       2 . A computer-implemented method for simulating operation of a physical system having a plurality of physical subsystems, comprising:
 simulating a first physical subsystem with a first continuous-time simulation on a first physical computing device;   accepting a request for export of information relating to a number n of state-related variables that characterize the state of the first physical subsystem in said simulating;   sending a first series of state-related messages, each message containing information relating to the value of at least one of the n state-related variables;   simulating a second physical subsystem with a second continuous-time simulation on a second physical computing device;   receiving in said second continuous-time simulation said first series of state-related messages from said first continuous-time simulation without said first series of state-related messages passing through a central communication process;   outputing data representative of a state of the second continuous-time simulation; wherein:
 the first physical subsystem interacts with the second physical subsystem; 
 the at least one state-related variable characterizes at least a portion of the interaction between the first physical subsystem and the second physical subsystem; and 
 the number n is at least two; and 
   sending a third series of state-related numerical values, wherein:
 at least one numerical value in the first series of state-related numerical values contains information relating to the values of a first proper subset of the set containing all n state-related variables; 
 at least one numerical value in the third series of state-related numerical values contains information relating to the values of a second proper subset of the set containing all n state variables, and 
 the second proper subset is different from the first proper subset; 
   
     wherein:
 the numerical values in the first series of state-related numerical values are sampled at a first rate in simulation time in the first simulation; 
 the numerical values in the third series of state-related numerical values are sampled at a second rate in simulation time in the first simulation; and 
 the first rate and the second rate are equal. 
 
   
   
       3 . A computer-implemented method for simulating operation of a physical system having a plurality of physical subsystems, comprising:
 simulating a first physical subsystem with a first continuous-time simulation on a first physical computing device;   accepting a request for export of information relating to a number n of state-related variables that characterize the state of the first physical subsystem in said simulating;   sending a first series of state-related messages, each message containing information relating to the value of at least one of the n state-related variables;   simulating a second physical subsystem with a second continuous-time simulation on a second physical computing device;   receiving in said second continuous-time simulation said first series of state-related messages from said first continuous-time simulation without said first series of state-related messages passing through a central communication process;   outputing data representative of a state of the second continuous-time simulation; wherein:   the first physical subsystem interacts with the second physical subsystem; and   the at least one state-related variable characterizes at least a portion of the interaction between the first physical subsystem and the second physical subsystem;   receiving the first series of state-related numerical values in a first output process in communication with a first output device; and   sending to the first output device a first set of information carried by a plurality of numerical values in the first series of state-related numerical values;   wherein the first output device is in communication with the first output process;   wherein said displaying comprises graphing a function of the first state-related variable versus an independent variable;   wherein the independent variable is time.   
   
   
       4 . A computer-implemented method for simulating operation of a physical system having a plurality of physical subsystems, comprising:
 simulating a first physical subsystem with a first continuous-time simulation on a first physical computing device;   accepting a request for export of information relating to a number n of state-related variables that characterize the state of the first physical subsystem in said simulating;   sending a first series of state-related messages, each message containing information relating to the value of at least one of the n state-related variables;   simulating a second physical subsystem with a second continuous-time simulation on a second physical computing device;   receiving in said second continuous-time simulation said first series of state-related messages from said first continuous-time simulation without said first series of state-related messages passing through a central communication process;   outputing data representative of a state of the second continuous-time simulation; wherein:   the first physical subsystem interacts with the second physical subsystem; and   the at least one state-related variable characterizes at least a portion of the interaction between the first physical subsystem and the second physical subsystem;   receiving the first series of state-related numerical values in a first output process in communication with a first output device; and   sending to the first output device a first set of information carried by a plurality of numerical values in the first series of state-related numerical values;   wherein the first output device is in communication with the first output process;   wherein said displaying comprises graphing a function of the first state-related variable versus an independent variable;   wherein the independent variable is one of the n state-related variables.   
   
   
       5 . A computer-implemented method for simulating operation of a physical system having a plurality of physical subsystems, comprising:
 simulating a first physical subsystem with a first continuous-time simulation on a first physical computing device;   accepting a request for export of information relating to a number n of state-related variables that characterize the state of the first physical subsystem in said simulating;   sending a first series of state-related messages, each message containing information relating to the value of at least one of the n state-related variables;   simulating a second physical subsystem with a second continuous-time simulation on a second physical computing device;   receiving in said second continuous-time simulation said first series of state-related messages from said first continuous-time simulation without said first series of state-related messages passing through a central communication process;   outputing data representative of a state of the second continuous-time simulation; wherein:   the first physical subsystem interacts with the second physical subsystem; and   the at least one state-related variable characterizes at least a portion of the interaction between the first physical subsystem and the second physical subsystem;   receiving the first series of state-related numerical values in a first output process in communication with a first output device; and   sending to the first output device a first set of information carried by a plurality of numerical values in the first series of state-related numerical values;   wherein the first output device is in communication with the first output process;   wherein said displaying comprises graphing a function of the first state-related variable versus an independent variable;   wherein the independent variable is a state-related variable in the simulation of the second physical subsystem.