Cirq

Notice

We only document what is different from Google’s qsimcirq. For more information, please review Google’s Documentation. For information on using qsim, refer to its documentation. For getting started using the NVIDIA cuQuantum Appliance with Cirq, visit the overview on NGC.

API Reference

qsimcirq.QSimOptions

qsimcirq.QSimOptions(
    max_fused_gate_size: int = 4,
    cpu_threads: int = 1,
    ev_noisy_repetitions: int = 1,
    disable_gpu: bool = False,
    gpu_mode: Union[int, Sequence[int]] = (0,),
    gpu_sim_threads: int = 256,
    gpu_state_threads: int = 512,
    gpu_data_blocks: int = 16,
    verbosity: int = 0,
    denormals_are_zeros: bool = False,
    n_subsvs: int = -1,
    use_sampler Union[bool, None] = None,
)

---

Keyword	Description
gpu_mode	The GPU simulator backend to use. If 1, the simulator backend will use cuStateVec. If n, an integer greater than 1, the simulator will use the multi-GPU backend with the first n devices. If a sequence of integers, the simulator will use the multi-GPU backend with devices whose ordinals match the values in the list. Default is to use the multi-GPU backend with device 0
n_subsvs	The number of state-vector partitions. This option is ignored unless the multi-GPU backend is in use. If -1, the number of partitions equals the number of GPUs. For optimal performance, ensure that the number of partitions equals the number of GPUs, and that both are a power of two
use_sampler	If None, the multi-GPU backend will use its sampler, and all other backends will use their default sampler. If True, use the multi-GPU backend’s sampler. If False, the multi-GPU backend’s sampler is disabled
disable_gpu	Whether or not to disable the GPU simulator backend. All GPU options are only considered when this is False (default). Note the difference from qsimcirq’s use_gpu keyword

---

Some examples

options = qsimcirq.QSimOptions(gpu_mode=1)  # use cuStateVec (single-GPU) backend
options = qsimcirq.QSimOptions(gpu_mode=(0,))  # use multi-GPU backend with GPU #0
options = qsimcirq.QSimOptions(gpu_mode=2)  # use multi-GPU backend with the first 2 devices
options = qsimcirq.QSimOptions(gpu_mode=(0,2))  # use multi-GPU backend with GPU #0 & #2