Resolve #528

scico/optimize/_admmaux.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# Copyright (C) 2020-2023 by SCICO Developers
+# Copyright (C) 2020-2024 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
@@ -371,15 +371,15 @@ class CircularConvolveSolver(LinearSubproblemSolver):
     r"""Solver for linear operators diagonalized in the DFT domain.
 
     Specialization of :class:`.LinearSubproblemSolver` for the case
-    where :code:`f` is an instance of :class:`.SquaredL2Loss`, the
-    forward operator :code:`f.A` is either an instance of
-    :class:`.Identity` or :class:`.CircularConvolve`, and the
-    :code:`C_i` are all shift invariant linear operators, examples of
-    which include instances of :class:`.Identity` as well as some
-    instances (depending on initializer parameters) of
-    :class:`.CircularConvolve` and :class:`.FiniteDifference`.
-    None of the instances of :class:`.CircularConvolve` may sum over any
-    of their axes.
+    where :code:`f` is ``None``, or an instance of
+    :class:`.SquaredL2Loss` with a forward operator :code:`f.A` that is
+    either an instance of :class:`.Identity` or
+    :class:`.CircularConvolve`, and the :code:`C_i` are all shift
+    invariant linear operators, examples of which include instances of
+    :class:`.Identity` as well as some instances (depending on
+    initializer parameters) of :class:`.CircularConvolve` and
+    :class:`.FiniteDifference`. None of the instances of
+    :class:`.CircularConvolve` may sum over any of their axes.
 
     Attributes:
         admm (:class:`.ADMM`): ADMM solver object to which the solver is
@@ -388,11 +388,29 @@ class CircularConvolveSolver(LinearSubproblemSolver):
             equation to be solved.
     """
 
-    def __init__(self):
-        """Initialize a :class:`CircularConvolveSolver` object."""
+    def __init__(self, ndims: Optional[int] = None):
+        """Initialize a :class:`CircularConvolveSolver` object.
+
+        Args:
+            ndims: Number of trailing dimensions of the input and kernel
+                involved in the :class:`.CircularConvolve` convolutions.
+                In most cases this value is automatically determined from
+                the optimization problem specification, but this is not
+                possible when :code:`f` is ``None`` and none of the
+                :code:`C_i` are of type :class:`.CircularConvolve`. When
+                not ``None``, this parameter overrides the automatic
+                mechanism.
+        """
+        self.ndims = ndims
 
     def internal_init(self, admm: soa.ADMM):
-        if admm.f is not None:
+        if admm.f is None:
+            is_cc = [isinstance(C, CircularConvolve) for C in admm.C_list]
+            if any(is_cc):
+                auto_ndims = admm.C_list[is_cc.index(True)].ndims
+            else:
+                auto_ndims = None
+        else:
             if not isinstance(admm.f, SquaredL2Loss):
                 raise TypeError(
                     "CircularConvolveSolver requires f to be a scico.loss.SquaredL2Loss; "
@@ -403,20 +421,27 @@ def internal_init(self, admm: soa.ADMM):
                     "CircularConvolveSolver requires f.A to be a scico.linop.CircularConvolve "
                     f"or scico.linop.Identity; got {type(admm.f.A)}."
                 )
+            auto_ndims = admm.f.A.ndims if isinstance(admm.f.A, CircularConvolve) else None
 
+        if self.ndims is None:
+            self.ndims = auto_ndims
         super().internal_init(admm)
 
         self.real_result = is_real_dtype(admm.C_list[0].input_dtype)
 
         # All of the C operators are assumed to be linear and shift invariant
         # but this is not checked.
         lhs_op_list = [
-            rho * CircularConvolve.from_operator(C.gram_op)
+            rho * CircularConvolve.from_operator(C.gram_op, ndims=self.ndims)
             for rho, C in zip(admm.rho_list, admm.C_list)
         ]
         A_lhs = reduce(lambda a, b: a + b, lhs_op_list)
         if self.admm.f is not None:
-            A_lhs += 2.0 * admm.f.scale * CircularConvolve.from_operator(admm.f.A.gram_op)
+            A_lhs += (
+                2.0
+                * admm.f.scale
+                * CircularConvolve.from_operator(admm.f.A.gram_op, ndims=self.ndims)
+            )
 
         self.A_lhs = A_lhs
 

scico/test/optimize/test_admm.py

@@ -363,23 +363,29 @@ def test_admm_quadratic_matrix(self):
         assert (snp.linalg.norm(self.grdA(x) - self.grdb) / snp.linalg.norm(self.grdb)) < 1e-5
 
 
+@pytest.mark.parametrize("extra_axis", (False, True))
+@pytest.mark.parametrize("center", (None, [-1.0, 2.5]))
 class TestCircularConvolveSolve:
-    def setup_method(self, method):
+
+    @pytest.fixture(scope="function", autouse=True)
+    def setup_and_teardown(self, extra_axis, center):
         np.random.seed(12345)
         Nx = 8
-        x = np.pad(np.ones((Nx, Nx), dtype=np.float32), Nx)
+        x = snp.pad(snp.ones((Nx, Nx), dtype=np.float32), Nx)
         Npsf = 3
         psf = snp.ones((Npsf, Npsf), dtype=np.float32) / (Npsf**2)
+        if extra_axis:
+            x = x[np.newaxis]
+            psf = psf[np.newaxis]
         self.A = linop.CircularConvolve(
-            h=psf,
-            input_shape=x.shape,
-            input_dtype=np.float32,
+            h=psf, input_shape=x.shape, ndims=2, input_dtype=np.float32, h_center=center
         )
         self.y = self.A(x)
         λ = 1e-2
         self.f = loss.SquaredL2Loss(y=self.y, A=self.A)
         self.g_list = [λ * functional.L1Norm()]
         self.C_list = [linop.FiniteDifference(input_shape=x.shape, circular=True)]
+        yield
 
     def test_admm(self):
         maxiter = 50
@@ -406,6 +412,60 @@ def test_admm(self):
             x0=self.A.adj(self.y),
             subproblem_solver=CircularConvolveSolver(),
         )
+        assert admm_dft.subproblem_solver.A_lhs.ndims == 2
+        x_dft = admm_dft.solve()
+        np.testing.assert_allclose(x_dft, x_lin, atol=1e-4, rtol=0)
+        assert metric.mse(x_lin, x_dft) < 1e-9
+
+
+@pytest.mark.parametrize("with_cconv", (False, True))
+class TestSpecialCaseCircularConvolveSolve:
+
+    @pytest.fixture(scope="function", autouse=True)
+    def setup_and_teardown(self, with_cconv):
+        np.random.seed(12345)
+        Nx = 8
+        x = snp.pad(snp.ones((1, Nx, Nx), dtype=np.float32), Nx)
+        if with_cconv:
+            Npsf = 3
+            psf = snp.ones((1, Npsf, Npsf), dtype=np.float32) / (Npsf**2)
+            C0 = linop.CircularConvolve(h=psf, input_shape=x.shape, ndims=2, input_dtype=np.float32)
+        else:
+            C0 = linop.FiniteDifference(input_shape=x.shape, axes=(1, 2), circular=True)
+        C1 = linop.Identity(input_shape=x.shape)
+        self.y = C0(x)
+        self.g_list = [loss.SquaredL2Loss(y=self.y), functional.L2Norm()]
+        self.C_list = [C0, C1]
+        self.with_cconv = with_cconv
+        yield
+
+    def test_admm(self):
+        maxiter = 50
+        ρ = 1e-1
+        rho_list = [ρ, ρ]
+        admm_lin = ADMM(
+            f=None,
+            g_list=self.g_list,
+            C_list=self.C_list,
+            rho_list=rho_list,
+            maxiter=maxiter,
+            itstat_options={"display": False},
+            x0=self.C_list[0].adj(self.y),
+            subproblem_solver=LinearSubproblemSolver(),
+        )
+        x_lin = admm_lin.solve()
+        ndims = None if self.with_cconv else 2
+        admm_dft = ADMM(
+            f=None,
+            g_list=self.g_list,
+            C_list=self.C_list,
+            rho_list=rho_list,
+            maxiter=maxiter,
+            itstat_options={"display": False},
+            x0=self.C_list[0].adj(self.y),
+            subproblem_solver=CircularConvolveSolver(ndims=ndims),
+        )
+        assert admm_dft.subproblem_solver.A_lhs.ndims == 2
         x_dft = admm_dft.solve()
         np.testing.assert_allclose(x_dft, x_lin, atol=1e-4, rtol=0)
         assert metric.mse(x_lin, x_dft) < 1e-9