Configuration

The set_max_qubits() and set_max_qubits_dm() functions control the maximum number of qubits allowed for state vector and density matrix allocations, respectively. These limits help prevent uncontrolled memory consumption; memory scales as 2^n * 16 bytes (complex128) for state vectors and 4^n * 16 bytes (complex128) for density matrices. The corresponding constant values can be accessed via get_max_qubits() and get_max_qubits_dm() functions. Both functions can also be configured via environment variables QIBO_MAX_QUBITS and QIBO_MAX_QUBITS_DM respectively.

import qibo

# Set maximum to 20 qubits for state vectors
qibo.set_max_qubits(20)

# Get current maximum
max_qubits = qibo.get_max_qubits()

# Set maximum to 15 qubits for density matrices
qibo.set_max_qubits_dm(15)

# Get current maximum for density matrices
max_qubits_dm = qibo.get_max_qubits_dm()