---
title: SciPyImaginaryEvolver (v0.46)
description: API reference for qiskit.algorithms.SciPyImaginaryEvolver in qiskit v0.46
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/0.46/qiskit.algorithms.SciPyImaginaryEvolver
---

# SciPyImaginaryEvolver

*class* `qiskit.algorithms.SciPyImaginaryEvolver(num_timesteps)`

[GitHub](https://github.com/qiskit/qiskit/tree/stable/0.46/qiskit/algorithms/time_evolvers/classical_methods/scipy_imaginary_evolver.py)

Bases: [`ImaginaryTimeEvolver`](/docs/api/qiskit/0.46/qiskit.algorithms.ImaginaryTimeEvolver "qiskit.algorithms.time_evolvers.imaginary_time_evolver.ImaginaryTimeEvolver")

Classical Evolver for imaginary time evolution.

Evolves an initial state $|\Psi\rangle$ for an imaginary time $\tau = it$ under a Hamiltonian $H$, as provided in the `evolution_problem`. Note that the precision of the evolver does not depend on the number of timesteps taken.

**Parameters**

**num\_timesteps** ([*int*](https://docs.python.org/3/library/functions.html#int)) – The number of timesteps in the simulation.

**Raises**

[**ValueError**](https://docs.python.org/3/library/exceptions.html#ValueError) – If num\_timesteps is not a positive integer.

## Methods

### evolve

`evolve(evolution_problem)`

Perform imaginary time evolution $\exp(-\tau H)|\Psi\rangle$.

Evolves an initial state $|\Psi\rangle$ for an imaginary time $\tau$ under a Hamiltonian $H$, as provided in the `evolution_problem`.

**Parameters**

**evolution\_problem** ([*TimeEvolutionProblem*](/docs/api/qiskit/0.46/qiskit.algorithms.TimeEvolutionProblem "qiskit.algorithms.time_evolvers.time_evolution_problem.TimeEvolutionProblem")) – The definition of the evolution problem.

**Returns**

Evolution result which includes an evolved quantum state.

**Return type**

[*TimeEvolutionResult*](/docs/api/qiskit/0.46/qiskit.algorithms.TimeEvolutionResult "qiskit.algorithms.time_evolvers.time_evolution_result.TimeEvolutionResult")