Leap’s Hybrid Solvers’ Timing Information

Timing-Related Fields

The table below lists the timing information returned from Leap’s quantum-classical hybrid solvers. Ocean users access to this information is from the info field in the dimod sampleset class, as in the example below.

>>> import dimod
>>> from dwave.system import LeapHybridSampler
...
>>> sampler = LeapHybridSampler(solver={'category': 'hybrid'})     
>>> bqm = dimod.generators.ran_r(1, 300)
>>> sampleset = sampler.sample(bqm)       
>>> sampleset.info     
{'qpu_access_time': 41990, 'charge_time': 2991424, 'run_time': 2991424}

Table 29 Timing Information from Leap’s Hybrid Solvers

Field	Meaning
run_time	Time, in microseconds, the hybrid solver spent working on the problem.
charge_time	Time, in microseconds, charged to the account. [1]
qpu_access_time	QPU time, in microseconds, used by the hybrid solver. [2]

[1]	charge_time and run_time may differ due to the time granularity of the solver. For example, if a hybrid solver has a time granularity of 0.5 sec and your submission specifies 4.7 sec, run_time might be 5 sec and charge_time 4.5 sec.

[2]

qpu_access_time might be zero for submissions with short run_time. Because the QPU is a shared, remote resource, the first set of samples from the QPU might not be received before a short explicitly-specified or default time_limit is reached. In such cases, the hybrid solver respects the time limitation and returns without the QPU having a chance to contribute to the solution. On the large, complex problems for which hybrid solvers are intended, this is unlikely to occur.