Deprecate sage_numerical_backends_coin in favor of cvxpy+cylp, upgrade cbc to 2.10.10

.github/workflows/ci-cygwin-standard.yml

@@ -117,7 +117,7 @@ jobs:
     with:
       stage: v-c
       previous_stages: iv
-      targets: sage_numerical_backends_coin
+      targets: cylp cvxopt
     needs: [cygwin-stage-iv]
 
   cygwin-stage-v-d:

build/pkgs/cbc/checksums.ini

@@ -1,5 +1,5 @@
 tarball=cbc-VERSION.tar.gz
-sha1=d937d6af1ee8838d44659ebd4cf7bbb1b20372ce
-md5=2134576233cc95cdfedc63991a4944ec
-cksum=1215468781
+sha1=1ead967d3d5610e3c434c9aec76a31ea90eb578f
+md5=c31255a6bd4ab7136f1d044f39c372da
+cksum=3510659652
 upstream_url=https://github.com/coin-or/Cbc/archive/refs/tags/releases/VERSION.tar.gz

build/pkgs/cbc/package-version.txt

@@ -1 +1 @@
-2.9.4.p0
+2.10.10

build/pkgs/sage_numerical_backends_coin/SPKG.rst

@@ -1,11 +1,16 @@
-sage_numerical_backends_coin: COIN-OR backend for Sage MixedIntegerLinearProgram
-================================================================================
+sage_numerical_backends_coin: COIN-OR backend for Sage MixedIntegerLinearProgram (deprecated)
+=============================================================================================
 
 Description
 -----------
 
 COIN-OR backend for Sage MixedIntegerLinearProgram
 
+This package is deprecated and will be removed soon.
+
+Install packages ``cvxpy`` and ``cylp`` instead.
+
+
 License
 -------
 

build/pkgs/sage_numerical_backends_coin/dependencies

@@ -1,4 +1,6 @@
-cbc cysignals $(SAGE_SRC)/sage/numerical/backends/generic_backend.pxd $(SAGE_SRC)/sage/cpython/string.pxd $(SAGE_SRC)/sage/cpython/string_impl.h | $(SAGERUNTIME) $(PYTHON_TOOLCHAIN) cython ipywidgets
+cylp cvxpy cbc cysignals $(SAGE_SRC)/sage/numerical/backends/generic_backend.pxd $(SAGE_SRC)/sage/cpython/string.pxd $(SAGE_SRC)/sage/cpython/string_impl.h | $(SAGERUNTIME) $(PYTHON_TOOLCHAIN) cython ipywidgets
 
 ----------
 All lines of this file are ignored except the first.
+
+cylp and cvxpy are the recommended replacement for this deprecated package - added them to the dependencies.

src/doc/en/thematic_tutorials/linear_programming.rst

@@ -447,10 +447,10 @@ following libraries are currently supported:
 * `CBC <https://github.com/coin-or/Cbc>`_: A solver from
   `COIN-OR <http://www.coin-or.org/>`_,
   provided under the Eclipse Public License (EPL), which is an open source
-  license but incompatible with GPL. CBC and the Sage CBC backend can be
-  installed using the shell command::
+  license but incompatible with GPL. Sage can use CBC via the optional
+  packages CyLP and CVXPy, which can be installed using the shell command::
 
-    $ sage -i -c sage_numerical_backends_coin
+    $ sage -i -c cylp cvxpy
 
 * `CPLEX
   <https://www.ibm.com/products/ilog-cplex-optimization-studio/>`_:

src/sage/numerical/backends/cvxpy_backend.pyx

@@ -336,6 +336,9 @@ cdef class CVXPYBackend:
             sage: p.row_name(1)
             'constraint_1'
         """
+        if not isinstance(coefficients, (list, tuple)):
+            # may be generator
+            coefficients = list(coefficients)
         last = len(self.Matrix)
         self.Matrix.append([])
         for i in range(len(self.objective_coefficients)):
@@ -930,3 +933,76 @@ cdef class CVXPYBackend:
             self.col_lower_bound[index] = value
         else:
             return self.col_lower_bound[index]
+
+    cpdef remove_constraint(self, int index):
+        """
+        Remove a linear constraint by index.
+
+        INPUT:
+
+        - ``index`` -- integer. The index of the constraint to remove.
+
+        EXAMPLES::
+
+            sage: from sage.numerical.backends.generic_backend import get_solver
+            sage: p = get_solver(solver="CVXPY")
+            sage: p.add_variables(5)
+            4
+            sage: row_index = p.nrows(); row_index
+            5
+            sage: p.add_linear_constraint(zip(range(5), range(5)), 2, 2)
+            sage: p.nrows() - row_index
+            1
+            sage: p.add_linear_constraint(zip(range(5), range(5)), 1, 1, name='foo')
+            sage: p.nrows() - row_index
+            2
+            sage: p.remove_constraint(row_index)
+            sage: p.nrows() - row_index
+            1
+            sage: p.row_name(row_index)
+            'foo'
+            sage: p.row_bounds(row_index)
+            (1, 1)
+            sage: p.cvxpy_problem().constraints[row_index:]
+            [Equality(Expression(AFFINE, UNKNOWN, ()), Constant(CONSTANT, NONNEGATIVE, ()))]
+        """
+        self.remove_constraints([index])
+
+    cpdef remove_constraints(self, indices):
+        r"""
+        Remove several constraints.
+
+        INPUT:
+
+        - ``indices`` -- iterable of integers. The indices of the constraints to remove,
+          in arbitrary order.
+
+        EXAMPLES::
+
+            sage: from sage.numerical.backends.generic_backend import get_solver
+            sage: p = get_solver(solver="CVXPY")
+            sage: p.add_variables(5)
+            4
+            sage: row_index = p.nrows(); row_index
+            5
+            sage: for i in range(3):
+            ....:     p.add_linear_constraint(zip(range(5), range(5)), None, 5)
+            sage: p.add_linear_constraint(zip(range(5), range(5)), 1, 1, name='foo')
+            sage: p.cvxpy_problem().constraints[row_index:]
+            [Inequality(Expression(AFFINE, UNKNOWN, ())),
+             Inequality(Expression(AFFINE, UNKNOWN, ())),
+             Inequality(Expression(AFFINE, UNKNOWN, ())),
+             Equality(Expression(AFFINE, UNKNOWN, ()), Constant(CONSTANT, NONNEGATIVE, ()))]
+            sage: p.remove_constraints(range(row_index, row_index + 3))
+            sage: p.cvxpy_problem().constraints[row_index:]
+            [Equality(Expression(AFFINE, UNKNOWN, ()), Constant(CONSTANT, NONNEGATIVE, ()))]
+        """
+        indices = sorted(indices)
+        constraints = list(self.problem.constraints)
+        for index in reversed(indices):
+            del self.Matrix[index]
+            del self.row_lower_bound[index]
+            del self.row_upper_bound[index]
+            del self.constraint_names[index]
+            del constraints[index]
+        self.problem = cvxpy.Problem(self.problem.objective, constraints)

src/sage/numerical/backends/generic_backend.pyx

@@ -1595,7 +1595,7 @@ def default_mip_solver(solver=None):
             return default_solver
 
         else:
-            for s in ["Cplex", "Gurobi", "Cvxpy/cbc", "Coin", "Glpk", "SCIP"]:
+            for s in ["Cplex", "Gurobi", "Cvxpy/cbc", "Glpk", "SCIP"]:
                 try:
                     default_mip_solver(s)
                     return s
@@ -1608,20 +1608,16 @@ def default_mip_solver(solver=None):
 
     solver = solver.capitalize()
 
+    if solver == "Coin":
+        solver = "Cvxpy/cbc"
+
     if solver == "Cplex":
         try:
             from sage_numerical_backends_cplex.cplex_backend import CPLEXBackend
             default_solver = solver
         except ImportError:
             raise ValueError("CPLEX is not available. Please refer to the documentation to install it.")
 
-    elif solver == "Coin":
-        try:
-            from sage_numerical_backends_coin.coin_backend import CoinBackend
-            default_solver = solver
-        except ImportError:
-            raise ValueError("COIN is not available. Please refer to the documentation to install it.")
-
     elif solver == "Cvxopt":
         try:
             from sage.numerical.backends.cvxopt_backend import CVXOPTBackend
@@ -1801,10 +1797,9 @@ cpdef GenericBackend get_solver(constraint_generation = False, solver = None, ba
         solver = solver.capitalize()
 
     if solver == "Coin":
-        from sage_numerical_backends_coin.coin_backend import CoinBackend
-        return CoinBackend()
+        solver = "Cvxpy/cbc"
 
-    elif solver == "Glpk":
+    if solver == "Glpk":
         from sage.numerical.backends.glpk_backend import GLPKBackend
         return GLPKBackend()