English

Computing Jacobi's $\theta$ in quasi-linear time

Number Theory 2015-11-16 v1

Abstract

Jacobi's θ\theta function has numerous applications in mathematics and computer science; a naive algorithm allows the computation of θ(z,τ)\theta(z,\tau), for z,τz, \tau verifying certain conditions, with precision PP in O(M(P)P)O(\mathcal{M}(P) \sqrt{P}) bit operations, where M(P)\mathcal{M}(P) denotes the number of operations needed to multiply two complex PP-bit numbers. We generalize an algorithm which computes specific values of the θ\theta function (the \textit{theta-constants}) in asymptotically faster time; this gives us an algorithm to compute θ(z,τ)\theta(z, \tau) with precision PP in O(M(P)logP)O(\mathcal{M}(P) \log P) bit operations, for any τF\tau \in \mathcal{F} and zz reduced using the quasi-periodicity of θ\theta.

Keywords

Cite

@article{arxiv.1511.04248,
  title  = {Computing Jacobi's $\theta$ in quasi-linear time},
  author = {Hugo Labrande},
  journal= {arXiv preprint arXiv:1511.04248},
  year   = {2015}
}
R2 v1 2026-06-22T11:44:26.024Z