SPSASamplerGradient¶

class SPSASamplerGradient(sampler, epsilon, batch_size=1, seed=None, options=None)[source]¶

Bases: qiskit.algorithms.gradients.base_sampler_gradient.BaseSamplerGradient

Compute the gradients of the sampling probability by the Simultaneous Perturbation Stochastic Approximation (SPSA) [1].

Reference: [1] J. C. Spall, Adaptive stochastic approximation by the simultaneous perturbation method in IEEE Transactions on Automatic Control, vol. 45, no. 10, pp. 1839-1853, Oct 2020, doi: 10.1109/TAC.2000.880982.

Parameters

sampler (BaseSampler) – The sampler used to compute the gradients.
epsilon (float) – The offset size for the SPSA gradients.
batch_size (int) – number of gradients to average.
seed (int | None) – The seed for a random perturbation vector.
options (Options | None) – Primitive backend runtime options used for circuit execution. The order of priority is: options in run method > gradient’s default options > primitive’s default setting. Higher priority setting overrides lower priority setting

Raises

ValueError – If epsilon is not positive.

Methods

`run`	Run the job of the sampler gradient on the given circuits.
`update_default_options`	Update the gradient's default options setting.

Attributes

options¶

Return the union of sampler options setting and gradient default options, where, if the same field is set in both, the gradient’s default options override the primitive’s default setting.

Return type: Options
Returns: The gradient default + sampler options.