Method and system for checkpointing during simulations

摘要

Method and system for more efficient checkpointing strategy in cross correlating (316) a forward (328) and backward (308) propagated wave such as in migrating (326) or inverting seismic data. The checkpointing strategy includes storing in memory forward simulation data at a checkpointed time step, wherein the stored data are sufficient to do a cross correlation at that time step but not to restart the forward simulation. At other checkpoints, a greater amount of data sufficient to restart the simulation may be stored in memory (314). Methods are disclosed for finding an optimal combination, i.e. one that minimizes computation time (1132), of the two types of checkpoints for a given amount of computer memory (1004), and for locating a checkpoint at an optimal time step (306, 1214, 1310). The optimal checkpointing strategy (1002) also may optimize (1408) on use of fast (1402) vs. slow (1404) storage.

主权项

1. A method for lowering a computational cost of a computer simulation, comprising:
performing a checkpointing strategy, wherein the checkpointing strategy comprises:
selecting a time step for storing a correlation checkpoint, wherein the correlation checkpoint comprises data used to correlate a forward propagated value generated by the computer simulation, and wherein the computer simulation cannot be restarted from the values stored in the correlation checkpoint;wherein the selecting a time step for storing a correlation checkpoint balances (i) reduction of computer storage requirements from storing a correlation checkpoint instead of a full state checkpoint, without ability to restart the computer simulation, versus (ii) reduction of computation time from storing a full state checkpoint from which the computer simulation can be restarted; allocating a storage space for the correlation checkpoint; and running the computer simulation at each of a plurality of time steps, wherein at each of the plurality of time steps:
a simulated value backwards propagated from measured data is correlated to the forward propagated value from the computer simulation, wherein the forward propagated value is stored in the correlation checkpoint.