Migration Guide

Migrating to 0.4

• CPU and CUDA have independent implementations behind shared device interfaces. All interfaces use the same native device selection; see Devices.
• eps_infeas_detect has been removed. Use eps_infeasible in C and the CLI, or InfeasibleTol in Python.
• Recompile C clients against the updated structures, and initialize parameters with set_default_parameters.

Migrating to 0.3

Version 0.3 adds quadratic conic models and changes the C and Python model construction APIs. This page covers the source changes needed by existing 0.2 callers.

C API

create_qp_problem has six new trailing arguments for variable and affine cones. Append neutral values for a plain QP:

qp_problem_t *problem = create_qp_problem(
    c, Q, R, D, A, con_lb, con_ub, var_lb, var_ub, objective_constant,
    0, NULL, NULL, NULL, 0, NULL);

For conic inputs and coordinate conventions, see cone_spec_t.

pdhcg_postsolve now returns nonzero after a complete primal-dual recovery and zero when postsolve fails or full dual recovery is unavailable:

if (!pdhcg_postsolve(info, result, original_problem)) {
    /* Handle postsolve failure. */
}

qp_problem_t and pdhg_parameters_t gained conic fields. Do not depend on their old binary layout. Recompile downstream code and initialize parameters through set_default_parameters before overriding individual fields.

Python API

Cone metadata is now columnar. Replace a list of dictionaries with one ConeSpec:

import numpy as np
from pdhcg import ConeSpec, ConeType

cones = ConeSpec(
    types=np.array([ConeType.SOC, ConeType.POWER], dtype=np.int32),
    starts=np.array([0, 4], dtype=np.int32),
    v_dims=np.array([2, 1], dtype=np.int32),
    power_alphas=np.array([0.0, 0.4]),
)

Pass this object as variable_cones or affine_cones when constructing a Model. Legacy list[dict] inputs intentionally raise TypeError.

CVXPY is an optional integration; see the CVXPY quick start.

Executable Location

A source build places the command-line executable at build/pdhcg. Installed packages place it in the installation prefix's bin directory.