Release notes

1.0

1.0.1

• Renamed solution statuses to use converged instead of converge. Callers comparing BiconvexProblem.status strings should update accordingly.

1.0.0

• Changed the BiconvexProblem constructor to accept x_var and y_var as separate arguments. The constructor materializes the two iterables, verifies that every member is a problem variable, and rejects overlapping groups. The groups may still be empty or non-exhaustive. Replace a grouped call such as BiconvexProblem(objective, ([x], [y]), constraints) with BiconvexProblem(objective, [x], [y], constraints).

• Unified direct and slack-penalized solves under BiconvexProblem.solve(). The default mode="direct" preserves the direct algorithm, while mode="penalty" selects the slack-penalized algorithm and permits an infeasible starting point. Omitting the penalty-only nu and slack_tol options, or explicitly passing None, gives effective defaults of 1 and 1e-6, respectively. nu must be finite and strictly positive; nu=0 is now rejected. A non-None value for either penalty-only option is also rejected in direct mode. The method keyword is available for CVXPY and passes through to each subproblem solve; replace the former DBCP selector method="penalty" with mode="penalty". The old slack_tolerance keyword is rejected with this error: 'slack_tolerance' was removed; use 'slack_tol'.

  Penalty results whose total slack exceeds slack_tol now use the statuses converge_with_slack and converge_inaccurate_with_slack, replacing converge_infeasible and converge_inaccurate_infeasible. Equality with slack_tol is accepted.

  BiconvexRelaxProblem has been removed from the public API. Constructing the migration stub raises this error: 'BiconvexRelaxProblem' was removed; use 'BiconvexProblem' and call solve(mode='penalty', ...). Repeated calls keep the current variable values, so callers can explicitly retry either mode or switch modes on the same object.

• Added penalty-formulation inspection to BiconvexProblem. The existing x_prob and y_prob properties continue to expose the direct fixed subproblems. The new penalty_prob, penalty_x_prob, penalty_y_prob, and slack_vars properties lazily construct and then return stable penalty problem and slack-variable objects.

• Replaced the public gap_tolerance solve argument with abs_tol and the keyword-only rel_tol. Both default to \(10^{-6}\), and DBCP stops when

  \[ |u-v| \leq \epsilon_{\mathrm{abs}} + \epsilon_{\mathrm{rel}}\max\{|u|,|v|\}. \]

  The legacy gap_tolerance keyword is rejected with guidance to use the new arguments. Setting rel_tol=0 yields an absolute-only stopping criterion.

0.2

The prototype series provided BiconvexProblem for direct alternating solves, BiconvexRelaxProblem for slack-relaxed solves, and convolve for biconvex convolution expressions.