gliss 0.0.1

Python interface to the Global Linear Ideal Stability Solver

gliss

gliss is the Python interface to the Global Linear Ideal Stability Solver. Version 0.0.1 provides the Mercier stability diagnostic for GVEC/CAS3D NetCDF equilibrium exports. The Linux wheel contains the compiled Fortran library and uses a small, hand-written ISO C binding; no f90wrap dependency is required.

Installation

python -m pip install gliss

NumPy is the only required Python dependency. The binary wheel also contains the native libraries needed by GLISS. Installing from source requires CMake, Ninja, and a Fortran compiler. LAPACK, PkgConfig, and the NetCDF C library are also required.

Mercier profile

from pathlib import Path

import gliss

s, d_mercier = gliss.mercier_profile(
    Path("equilibrium_export.nc"),
    n_theta=64,
    n_zeta=64,
)
worst = gliss.mercier_objective("equilibrium_export.nc")

s and d_mercier are one-dimensional NumPy float64 arrays with one entry per retained radial surface. GLISS uses the D_Mercier convention: positive values are unstable. mercier_objective returns max(d_mercier), so a larger positive result is less stable.

The input must be a regular file in the GVEC/CAS3D export format. Angular quadrature sizes must be positive integers. Invalid Python arguments raise TypeError, ValueError, or FileNotFoundError; invalid exports and solver failures raise RuntimeError with the native status code.

SIMSOPT

Install the optional dependency and import the adapter explicitly:

python -m pip install "gliss[simsopt]"

from gliss.simsopt import MercierPenalty

penalty = MercierPenalty("equilibrium_export.nc")
value = penalty.J()

MercierPenalty is a leaf Optimizable. It has no equilibrium degrees of freedom and no analytic derivative in version 0.0.1. Update export_path after an external equilibrium solve before evaluating it again.

Native library and ABI

gliss.version() reports the loaded native version. The Python package checks ABI version 1 before every native call and rejects an incompatible library. Platform wheels load their bundled library automatically. Developers can test a local build explicitly:

cmake -S . -B build -G Ninja
cmake --build build --target gliss_c
GLISS_LIB=$PWD/build/libgliss_c.so python -c \
  'import gliss; print(gliss.version())'

GLISS_LIB deliberately overrides the bundled library. This is a development and debugging facility, not required for normal use.