FLINT3.7.0-dev
/

fmpz_factor_ecm_double

Synopsis#include <flint/fmpz_factor.h>
void fmpz_factor_ecm_double(nn_ptr x, nn_ptr z, nn_ptr x0, nn_ptr z0, nn_ptr n, ecm_t ecm_inf)source

Sets (x:z)(x : z) to 2(x0:z0)2 (x_0 : z_0) by Montgomery's doubling formula x=(x0+z0)2(x0−z0)2x = (x_0 + z_0)^2 (x_0 - z_0)^2, z=4x0z0((x0−z0)2+a24⋅4x0z0)z = 4 x_0 z_0 \bigl((x_0 - z_0)^2 + a_{24} \cdot 4 x_0 z_0\bigr) modulo nn.

Cite this page

The FLINT team, “fmpz_factor_ecm_double (fmpz_factor.h),” FLINT: Fast Library for Number Theory, documentation, version 3.7.0-dev, 2026. https://flintlib.org/doc/fmpz_factor/fmpz_factor_ecm_double.html (generated 2026-11-02).