Add support for state save/load, and other minor improvements

scico/optimize/_admm.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# Copyright (C) 2020-2023 by SCICO Developers
+# Copyright (C) 2020-2025 by SCICO Developers
 # All rights reserved. BSD 3-clause License.
 # This file is part of the SCICO package. Details of the copyright and
 # user license can be found in the 'LICENSE' file distributed with the
@@ -197,8 +197,10 @@ def _itstat_extra_fields(self):
 
         return itstat_fields, itstat_attrib
 
-    def minimizer(self):
-        """Return current estimate of the functional mimimizer."""
+    def _state_variable_names(self) -> List[str]:
+        return ["z_list", "z_list_old", "u_list"]
+
+    def minimizer(self) -> Union[Array, BlockArray]:
         return self.x
 
     def objective(

scico/optimize/_ladmm.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# Copyright (C) 2021-2024 by SCICO Developers
+# Copyright (C) 2021-2025 by SCICO Developers
 # All rights reserved. BSD 3-clause License.
 # This file is part of the SCICO package. Details of the copyright and
 # user license can be found in the 'LICENSE' file distributed with the
@@ -142,8 +142,10 @@ def _itstat_extra_fields(self):
         itstat_attrib = ["norm_primal_residual()", "norm_dual_residual()"]
         return itstat_fields, itstat_attrib
 
-    def minimizer(self):
-        """Return current estimate of the functional mimimizer."""
+    def _state_variable_names(self) -> List[str]:
+        return ["x", "z", "z_old", "u"]
+
+    def minimizer(self) -> Union[Array, BlockArray]:
         return self.x
 
     def objective(

scico/optimize/_padmm.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# Copyright (C) 2022-2024 by SCICO Developers
+# Copyright (C) 2022-2025 by SCICO Developers
 # All rights reserved. BSD 3-clause License.
 # This file is part of the SCICO package. Details of the copyright and
 # user license can be found in the 'LICENSE' file distributed with the
@@ -137,8 +137,10 @@ def _itstat_extra_fields(self):
         itstat_attrib = ["norm_primal_residual()", "norm_dual_residual()"]
         return itstat_fields, itstat_attrib
 
-    def minimizer(self):
-        """Return current estimate of the functional mimimizer."""
+    def _state_variable_names(self) -> List[str]:
+        return ["x", "z", "z_old", "u", "u_old"]
+
+    def minimizer(self) -> Union[Array, BlockArray]:
         return self.x
 
     def objective(

scico/optimize/_pgm.py

@@ -137,11 +137,9 @@ def _itstat_extra_fields(self):
         return itstat_fields, itstat_attrib
 
     def _state_variable_names(self) -> List[str]:
-        """Get optimizer state variable names."""
         return ["x", "L"]
 
-    def minimizer(self):
-        """Return current estimate of the functional mimimizer."""
+    def minimizer(self) -> Union[Array, BlockArray]:
         return self.x
 
     def objective(self, x: Optional[Union[Array, BlockArray]] = None) -> float:

scico/optimize/_primaldual.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# Copyright (C) 2021-2023 by SCICO Developers
+# Copyright (C) 2021-2025 by SCICO Developers
 # All rights reserved. BSD 3-clause License.
 # This file is part of the SCICO package. Details of the copyright and
 # user license can be found in the 'LICENSE' file distributed with the
@@ -160,8 +160,10 @@ def _itstat_extra_fields(self):
         itstat_attrib = ["norm_primal_residual()", "norm_dual_residual()"]
         return itstat_fields, itstat_attrib
 
-    def minimizer(self):
-        """Return current estimate of the functional mimimizer."""
+    def _state_variable_names(self) -> List[str]:
+        return ["x", "x_old", "z", "z_old"]
+
+    def minimizer(self) -> Union[Array, BlockArray]:
         return self.x
 
     def objective(

scico/test/optimize/test_admm.py

@@ -1,3 +1,6 @@
+import os
+import tempfile
+
 import numpy as np
 
 import pytest
@@ -145,6 +148,25 @@ def test_admm_generic(self):
         x = admm_.solve()
         assert (snp.linalg.norm(self.grdA(x) - self.grdb) / snp.linalg.norm(self.grdb)) < 1e-3
 
+        with tempfile.TemporaryDirectory() as tmpdir:
+            path = os.path.join(tmpdir, "admm.npz")
+            admm_.save_state(path)
+            admm2 = ADMM(
+                f=f,
+                g_list=g_list,
+                C_list=C_list,
+                rho_list=rho_list,
+                maxiter=maxiter,
+                itstat_options={"display": False},
+                x0=A.adj(self.y),
+                subproblem_solver=GenericSubproblemSolver(
+                    minimize_kwargs={"options": {"maxiter": 50}}
+                ),
+            )
+            admm2.load_state(path)
+            np.testing.assert_allclose(admm_.z_list[0], admm2.z_list[0], rtol=1e-7)
+            np.testing.assert_allclose(admm_.u_list[0], admm2.u_list[0], rtol=1e-7)
+
     def test_admm_quadratic_scico(self):
         maxiter = 25
         ρ = 4e-1