Add parameter support to Python bindings

sparsediffpy/_bindings/atoms/const_scalar_mult.h

@@ -3,8 +3,10 @@
 
 #include "bivariate.h"
 #include "common.h"
+#include "subexpr.h"
 
-/* Constant scalar multiplication: a * f(x) where a is a constant double */
+/* Constant scalar multiplication: a * f(x) where a is a constant double.
+ * Creates a fixed parameter node for the scalar and calls new_scalar_mult. */
 static PyObject *py_make_const_scalar_mult(PyObject *self, PyObject *args)
 {
     PyObject *child_capsule;
@@ -22,11 +24,20 @@ static PyObject *py_make_const_scalar_mult(PyObject *self, PyObject *args)
         return NULL;
     }
 
-    expr *node = new_const_scalar_mult(a, child);
+    /* Create a 1x1 fixed parameter for the scalar value */
+    expr *a_node = new_parameter(1, 1, PARAM_FIXED, child->n_vars, &a);
+    if (!a_node)
+    {
+        PyErr_SetString(PyExc_RuntimeError, "failed to create scalar parameter node");
+        return NULL;
+    }
+
+    expr *node = new_scalar_mult(a_node, child);
+
     if (!node)
     {
         PyErr_SetString(PyExc_RuntimeError,
-                        "failed to create const_scalar_mult node");
+                        "failed to create scalar_mult node");
         return NULL;
     }
     expr_retain(node); /* Capsule owns a reference */

sparsediffpy/_bindings/atoms/const_vector_mult.h

@@ -3,9 +3,10 @@
 
 #include "bivariate.h"
 #include "common.h"
+#include "subexpr.h"
 
-/* Constant vector elementwise multiplication: a ∘ f(x) where a is a constant vector
- */
+/* Constant vector elementwise multiplication: a ∘ f(x) where a is a constant vector.
+ * Creates a fixed parameter node for the vector and calls new_vector_mult. */
 static PyObject *py_make_const_vector_mult(PyObject *self, PyObject *args)
 {
     PyObject *child_capsule;
@@ -42,14 +43,24 @@ static PyObject *py_make_const_vector_mult(PyObject *self, PyObject *args)
 
     double *a_data = (double *) PyArray_DATA(a_array);
 
-    expr *node = new_const_vector_mult(a_data, child);
-
+    /* Create a fixed parameter node for the vector */
+    expr *a_node = new_parameter(child->d1, child->d2, PARAM_FIXED, child->n_vars,
+                                 a_data);
     Py_DECREF(a_array);
 
+    if (!a_node)
+    {
+        PyErr_SetString(PyExc_RuntimeError,
+                        "failed to create vector parameter node");
+        return NULL;
+    }
+
+    expr *node = new_vector_mult(a_node, child);
+
     if (!node)
     {
         PyErr_SetString(PyExc_RuntimeError,
-                        "failed to create const_vector_mult node");
+                        "failed to create vector_mult node");
         return NULL;
     }
     expr_retain(node); /* Capsule owns a reference */

sparsediffpy/_bindings/atoms/constant.h

@@ -2,6 +2,7 @@
 #define ATOM_CONSTANT_H
 
 #include "common.h"
+#include "subexpr.h"
 
 static PyObject *py_make_constant(PyObject *self, PyObject *args)
 {
@@ -19,8 +20,8 @@ static PyObject *py_make_constant(PyObject *self, PyObject *args)
         return NULL;
     }
 
-    expr *node =
-        new_constant(d1, d2, n_vars, (const double *) PyArray_DATA(values_array));
+    expr *node = new_parameter(d1, d2, PARAM_FIXED, n_vars,
+                               (const double *) PyArray_DATA(values_array));
     Py_DECREF(values_array);
 
     if (!node)

sparsediffpy/_bindings/atoms/left_matmul.h

@@ -3,15 +3,27 @@
 
 #include "bivariate.h"
 #include "common.h"
+#include "subexpr.h"
 
-/* Left matrix multiplication: A @ f(x) where A is a constant matrix */
+/* Left matrix multiplication: A @ f(x).
+ *
+ * Unified binding for both fixed-constant and updatable-parameter cases.
+ * Python signature:
+ *   make_left_matmul(param_or_none, child, data, indices, indptr, m, n)
+ *
+ * - param_or_none: None for fixed constants (a PARAM_FIXED parameter is created
+ *   internally), or an existing parameter capsule for updatable parameters.
+ * - child: the child expression capsule f(x).
+ * - data, indices, indptr, m, n: CSR arrays defining the sparsity pattern and
+ *   initial values of the matrix A. */
 static PyObject *py_make_left_matmul(PyObject *self, PyObject *args)
 {
+    PyObject *param_obj;
     PyObject *child_capsule;
     PyObject *data_obj, *indices_obj, *indptr_obj;
     int m, n;
-    if (!PyArg_ParseTuple(args, "OOOOii", &child_capsule, &data_obj, &indices_obj,
-                          &indptr_obj, &m, &n))
+    if (!PyArg_ParseTuple(args, "OOOOOii", &param_obj, &child_capsule, &data_obj,
+                          &indices_obj, &indptr_obj, &m, &n))
     {
         return NULL;
     }
@@ -38,18 +50,55 @@ static PyObject *py_make_left_matmul(PyObject *self, PyObject *args)
         return NULL;
     }
 
-    int nnz = (int) PyArray_SIZE(data_array);
+    double *csr_data = (double *) PyArray_DATA(data_array);
+    int *csr_indices = (int *) PyArray_DATA(indices_array);
+    int *csr_indptr = (int *) PyArray_DATA(indptr_array);
+    int nnz = csr_indptr[m];
+
+    /* Build CSR matrix from Python arrays */
     CSR_Matrix *A = new_csr_matrix(m, n, nnz);
-    memcpy(A->x, PyArray_DATA(data_array), nnz * sizeof(double));
-    memcpy(A->i, PyArray_DATA(indices_array), nnz * sizeof(int));
-    memcpy(A->p, PyArray_DATA(indptr_array), (m + 1) * sizeof(int));
+    memcpy(A->p, csr_indptr, (m + 1) * sizeof(int));
+    memcpy(A->i, csr_indices, nnz * sizeof(int));
+    memcpy(A->x, csr_data, nnz * sizeof(double));
+
+    /* Determine param_node: use passed capsule, or create PARAM_FIXED internally */
+    expr *param_node;
+    if (param_obj == Py_None)
+    {
+        /* Fixed constant: pass CSR data directly (values are already in CSR order) */
+        param_node = new_parameter(nnz, 1, PARAM_FIXED, child->n_vars, csr_data);
+
+        if (!param_node)
+        {
+            free_csr_matrix(A);
+            Py_DECREF(data_array);
+            Py_DECREF(indices_array);
+            Py_DECREF(indptr_array);
+            PyErr_SetString(PyExc_RuntimeError,
+                            "failed to create matrix parameter node");
+            return NULL;
+        }
+    }
+    else
+    {
+        param_node = (expr *) PyCapsule_GetPointer(param_obj, EXPR_CAPSULE_NAME);
+        if (!param_node)
+        {
+            free_csr_matrix(A);
+            Py_DECREF(data_array);
+            Py_DECREF(indices_array);
+            Py_DECREF(indptr_array);
+            PyErr_SetString(PyExc_ValueError, "invalid param capsule");
+            return NULL;
+        }
+    }
 
     Py_DECREF(data_array);
     Py_DECREF(indices_array);
     Py_DECREF(indptr_array);
 
-    expr *node = new_left_matmul(child, A);
-    free_csr_matrix(A);
+    expr *node = new_left_matmul(param_node, child, A);
+    free_csr_matrix(A); /* constructor copies it */
 
     if (!node)
     {

sparsediffpy/_bindings/atoms/parameter.h

@@ -0,0 +1,26 @@
+#ifndef ATOM_PARAMETER_H
+#define ATOM_PARAMETER_H
+
+#include "common.h"
+
+/* Updatable parameter: make_parameter(d1, d2, param_id, n_vars)
+ * Values are set later via problem_update_params. */
+static PyObject *py_make_parameter(PyObject *self, PyObject *args)
+{
+    int d1, d2, param_id, n_vars;
+    if (!PyArg_ParseTuple(args, "iiii", &d1, &d2, &param_id, &n_vars))
+    {
+        return NULL;
+    }
+
+    expr *node = new_parameter(d1, d2, param_id, n_vars, NULL);
+    if (!node)
+    {
+        PyErr_SetString(PyExc_RuntimeError, "failed to create parameter node");
+        return NULL;
+    }
+    expr_retain(node); /* Capsule owns a reference */
+    return PyCapsule_New(node, EXPR_CAPSULE_NAME, expr_capsule_destructor);
+}
+
+#endif /* ATOM_PARAMETER_H */

sparsediffpy/_bindings/atoms/right_matmul.h

@@ -3,15 +3,27 @@
 
 #include "bivariate.h"
 #include "common.h"
+#include "subexpr.h"
 
-/* Right matrix multiplication: f(x) @ A where A is a constant matrix */
+/* Right matrix multiplication: f(x) @ A where A is a constant or parameter matrix.
+ *
+ * Unified binding for both fixed-constant and updatable-parameter cases.
+ * Python signature:
+ *   make_right_matmul(param_or_none, child, data, indices, indptr, m, n)
+ *
+ * - param_or_none: None for fixed constants (a PARAM_FIXED parameter is created
+ *   internally), or an existing parameter capsule for updatable parameters.
+ * - child: the child expression capsule f(x).
+ * - data, indices, indptr, m, n: CSR arrays defining the sparsity pattern and
+ *   initial values of the matrix A. */
 static PyObject *py_make_right_matmul(PyObject *self, PyObject *args)
 {
+    PyObject *param_obj;
     PyObject *child_capsule;
     PyObject *data_obj, *indices_obj, *indptr_obj;
     int m, n;
-    if (!PyArg_ParseTuple(args, "OOOOii", &child_capsule, &data_obj, &indices_obj,
-                          &indptr_obj, &m, &n))
+    if (!PyArg_ParseTuple(args, "OOOOOii", &param_obj, &child_capsule, &data_obj,
+                          &indices_obj, &indptr_obj, &m, &n))
     {
         return NULL;
     }
@@ -38,18 +50,55 @@ static PyObject *py_make_right_matmul(PyObject *self, PyObject *args)
         return NULL;
     }
 
-    int nnz = (int) PyArray_SIZE(data_array);
+    double *csr_data = (double *) PyArray_DATA(data_array);
+    int *csr_indices = (int *) PyArray_DATA(indices_array);
+    int *csr_indptr = (int *) PyArray_DATA(indptr_array);
+    int nnz = csr_indptr[m];
+
+    /* Build CSR matrix from Python arrays */
     CSR_Matrix *A = new_csr_matrix(m, n, nnz);
-    memcpy(A->x, PyArray_DATA(data_array), nnz * sizeof(double));
-    memcpy(A->i, PyArray_DATA(indices_array), nnz * sizeof(int));
-    memcpy(A->p, PyArray_DATA(indptr_array), (m + 1) * sizeof(int));
+    memcpy(A->p, csr_indptr, (m + 1) * sizeof(int));
+    memcpy(A->i, csr_indices, nnz * sizeof(int));
+    memcpy(A->x, csr_data, nnz * sizeof(double));
+
+    /* Determine param_node: use passed capsule, or create PARAM_FIXED internally */
+    expr *param_node;
+    if (param_obj == Py_None)
+    {
+        /* Fixed constant: pass CSR data directly (values are already in CSR order) */
+        param_node = new_parameter(nnz, 1, PARAM_FIXED, child->n_vars, csr_data);
+
+        if (!param_node)
+        {
+            free_csr_matrix(A);
+            Py_DECREF(data_array);
+            Py_DECREF(indices_array);
+            Py_DECREF(indptr_array);
+            PyErr_SetString(PyExc_RuntimeError,
+                            "failed to create matrix parameter node");
+            return NULL;
+        }
+    }
+    else
+    {
+        param_node = (expr *) PyCapsule_GetPointer(param_obj, EXPR_CAPSULE_NAME);
+        if (!param_node)
+        {
+            free_csr_matrix(A);
+            Py_DECREF(data_array);
+            Py_DECREF(indices_array);
+            Py_DECREF(indptr_array);
+            PyErr_SetString(PyExc_ValueError, "invalid param capsule");
+            return NULL;
+        }
+    }
 
     Py_DECREF(data_array);
     Py_DECREF(indices_array);
     Py_DECREF(indptr_array);
 
-    expr *node = new_right_matmul(child, A);
-    free_csr_matrix(A);
+    expr *node = new_right_matmul(param_node, child, A);
+    free_csr_matrix(A); /* constructor copies it */
 
     if (!node)
     {

sparsediffpy/_bindings/atoms/scalar_mult.h

@@ -0,0 +1,44 @@
+#ifndef ATOM_SCALAR_MULT_H
+#define ATOM_SCALAR_MULT_H
+
+#include "bivariate.h"
+#include "common.h"
+
+/* Parameter scalar multiplication: param * f(x) where param is a parameter capsule.
+ * Python name: make_param_scalar_mult(param_capsule, child_capsule) */
+static PyObject *py_make_param_scalar_mult(PyObject *self, PyObject *args)
+{
+    PyObject *param_capsule;
+    PyObject *child_capsule;
+
+    if (!PyArg_ParseTuple(args, "OO", &param_capsule, &child_capsule))
+    {
+        return NULL;
+    }
+
+    expr *param_node =
+        (expr *) PyCapsule_GetPointer(param_capsule, EXPR_CAPSULE_NAME);
+    if (!param_node)
+    {
+        PyErr_SetString(PyExc_ValueError, "invalid param capsule");
+        return NULL;
+    }
+
+    expr *child = (expr *) PyCapsule_GetPointer(child_capsule, EXPR_CAPSULE_NAME);
+    if (!child)
+    {
+        PyErr_SetString(PyExc_ValueError, "invalid child capsule");
+        return NULL;
+    }
+
+    expr *node = new_scalar_mult(param_node, child);
+    if (!node)
+    {
+        PyErr_SetString(PyExc_RuntimeError, "failed to create scalar_mult node");
+        return NULL;
+    }
+    expr_retain(node);
+    return PyCapsule_New(node, EXPR_CAPSULE_NAME, expr_capsule_destructor);
+}
+
+#endif /* ATOM_SCALAR_MULT_H */