sbillinge · Oct 16, 2026 · Oct 7, 2026 · Oct 7, 2026 · Oct 7, 2026 · Oct 7, 2026
diff --git a/.github/workflows/check-news-item.yml b/.github/workflows/check-news-item.yml
@@ -3,7 +3,7 @@ name: Check for News
 on:
   pull_request_target:
     branches:
-      - main  # GitHub does not evaluate expressions in trigger filters; edit this value if your base branch is not main
+      - main # GitHub does not evaluate expressions in trigger filters; edit this value if your base branch is not main
 
 jobs:
   check-news-item:

diff --git a/.github/workflows/matrix-and-codecov.yml b/.github/workflows/matrix-and-codecov.yml
@@ -17,5 +17,8 @@ jobs:
       project: diffpy.cmistructure
       c_extension: false
       headless: false
+      run: |
+        set -Eeuo pipefail
+        python -m pip install --no-deps diffpy.srfit==3.4.0rc0
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
diff --git a/.github/workflows/tests-on-pr.yml b/.github/workflows/tests-on-pr.yml
@@ -11,5 +11,8 @@ jobs:
       project: diffpy.cmistructure
       c_extension: false
       headless: false
+      run: |
+        set -Eeuo pipefail
+        python -m pip install --no-deps diffpy.srfit==3.4.0rc0
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
diff --git a/LICENSE_DANSE.rst b/LICENSE_DANSE.rst
@@ -0,0 +1,34 @@
+This program is part of the DiffPy and DANSE open-source projects at Columbia
+University and is available subject to the conditions and terms laid out below.
+
+Copyright (c) 2008-2011, The Trustees of Columbia University in
+the City of New York.  All rights reserved.
+
+For more information please visit the diffpy web-page at
+    http://www.diffpy.org
+or email Prof. Simon Billinge at sb2896@columbia.edu.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright notice, this
+    list of conditions and the following disclaimer.
+
+  * Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions and the following disclaimer in the documentation
+    and/or other materials provided with the distribution.
+
+  * Neither the names of COLUMBIA UNIVERSITY, MICHIGAN STATE UNIVERSITY nor the
+    names of their contributors may be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/cookiecutter.json b/cookiecutter.json
@@ -13,8 +13,8 @@
   "package_dir_name": "diffpy.cmistructure",
   "project_short_description": "diffpy.cmi package for doing refinements with structure objects",
   "project_keywords": "diffraction, PDF, X-ray, neutron",
-  "minimum_supported_python_version": "3.12",
-  "maximum_supported_python_version": "3.14",
+  "minimum_supported_python_version": "3.11",
+  "maximum_supported_python_version": "3.13",
   "project_needs_c_code_compiled": "No",
   "project_has_gui_tests": "No"
 }
diff --git a/docs/source/api/diffpy.cmistructure.example_package.rst b/docs/source/api/diffpy.cmistructure.example_package.rst
diff --git a/docs/source/api/diffpy.cmistructure.rst b/docs/source/api/diffpy.cmistructure.rst
@@ -1,30 +1,68 @@
 :tocdepth: -1
 
-|title|
-=======
-
-.. |title| replace:: diffpy.cmistructure package
+diffpy.cmistructure package
+===========================
 
 .. automodule:: diffpy.cmistructure
     :members:
     :undoc-members:
     :show-inheritance:
 
-Subpackages
------------
-
-.. toctree::
-   diffpy.cmistructure.example_package
-
 Submodules
 ----------
 
-|module|
---------
+diffpy.cmistructure.objcrystparset module
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. automodule:: diffpy.cmistructure.objcrystparset
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+diffpy.cmistructure.basestructureparset module
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. automodule:: diffpy.cmistructure.basestructureparset
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+diffpy.cmistructure.srrealparset module
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. automodule:: diffpy.cmistructure.srrealparset
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+diffpy.cmistructure.diffpyparset module
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. automodule:: diffpy.cmistructure.diffpyparset
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+diffpy.cmistructure.cctbxparset module
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. automodule:: diffpy.cmistructure.cctbxparset
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+diffpy.cmistructure.bvsrestraint module
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. automodule:: diffpy.cmistructure.bvsrestraint
+    :members:
+    :undoc-members:
+    :show-inheritance:
 
-.. |module| replace:: diffpy.cmistructure.example_submodule module
+diffpy.cmistructure.sgconstraints module
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-.. automodule:: diffpy.cmistructure.example_submodule
+.. automodule:: diffpy.cmistructure.sgconstraints
     :members:
     :undoc-members:
     :show-inheritance:
diff --git a/news/migrate-structure.rst b/news/migrate-structure.rst
@@ -0,0 +1,23 @@
+**Added:**
+
+* No news added.
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>
diff --git a/pyproject.toml b/pyproject.toml
@@ -14,7 +14,7 @@ maintainers = [
 description = "diffpy.cmi package for doing refinements with structure objects"
 keywords = ['diffraction', 'PDF', 'X-ray', 'neutron']
 readme = "README.rst"
-requires-python = ">=3.12, <3.15"
+requires-python = ">=3.11, <3.14"
 classifiers = [
         'Development Status :: 5 - Production/Stable',
         'Environment :: Console',
@@ -25,9 +25,9 @@ classifiers = [
         'Operating System :: Microsoft :: Windows',
         'Operating System :: POSIX',
         'Operating System :: Unix',
+        'Programming Language :: Python :: 3.11',
         'Programming Language :: Python :: 3.12',
         'Programming Language :: Python :: 3.13',
-        'Programming Language :: Python :: 3.14',
         'Topic :: Scientific/Engineering :: Physics',
         'Topic :: Scientific/Engineering :: Chemistry',
 ]
@@ -49,11 +49,17 @@ exclude = []  # exclude packages matching these glob patterns (empty by default)
 namespaces = false  # to disable scanning PEP 420 namespaces (true by default)
 
 [project.scripts]
-diffpy-cmistructure = "diffpy.cmistructure.app:main"
+diffpy-cmistructure = "diffpy.cmistructure.cmistructure_app:main"
 
 [tool.setuptools.dynamic]
 dependencies = {file = ["requirements/pip.txt"]}
 
+[tool.pytest.ini_options]
+# Fail when cmistructure source calls one of its own deprecated names.
+filterwarnings = [
+    "error:'diffpy\\.cmistructure\\.:DeprecationWarning:diffpy\\.cmistructure",
+]
+
 [tool.codespell]
 exclude-file = ".codespell/ignore_lines.txt"
 ignore-words = ".codespell/ignore_words.txt"

diff --git a/requirements/conda.txt b/requirements/conda.txt
@@ -1 +1,5 @@
 numpy
+diffpy.srreal
+diffpy.srfit
+diffpy.structure
+pyobjcryst
diff --git a/requirements/pip.txt b/requirements/pip.txt
@@ -1 +1,5 @@
 numpy
+diffpy.srreal
+diffpy.srfit
+diffpy.structure
+pyobjcryst
diff --git a/requirements/tests.txt b/requirements/tests.txt
@@ -4,3 +4,4 @@ codecov
 coverage
 pytest-cov
 pytest-env
+pyobjcryst
diff --git a/src/diffpy/__init__.py b/src/diffpy/__init__.py
@@ -12,3 +12,6 @@
 # See LICENSE.rst for license information.
 #
 ##############################################################################
+from pkgutil import extend_path
+
+__path__ = extend_path(__path__, __name__)
diff --git a/src/diffpy/cmistructure/__init__.py b/src/diffpy/cmistructure/__init__.py
@@ -12,11 +12,65 @@
 # See LICENSE.rst for license information.
 #
 ##############################################################################
-"""diffpy.cmi package for doing refinements with structure objects"""
+"""Modules and classes that adapt structure representations to the
+ParameterSet interface and automatic structure constraint generation
+from space group information."""
+
+from diffpy.cmistructure.sgconstraints import constrain_as_space_group
 
 # package version
 from diffpy.cmistructure.version import __version__  # noqa
 
+__all__ = ["constrain_as_space_group", "structure_to_parameter_set"]
+
+
+def structure_to_parameter_set(name, structure):
+    """Create a ParameterSet adapted to a structure object.
+
+    The adapter is chosen from the type of `structure`. Supported types are
+    diffpy.structure.Structure, pyobjcryst.crystal.Crystal,
+    pyobjcryst.molecule.Molecule and cctbx.crystal.special_position_settings.
+
+    Parameters
+    ----------
+    name : str
+        The name to give the structure.
+    structure : object
+        The structure object to adapt.
+
+    Returns
+    -------
+    BaseStructureParSet
+        The ParameterSet adapting `structure`.
+
+    Raises
+    ------
+    TypeError
+        If `structure` is not one of the supported structure types.
+    """
+    from diffpy.cmistructure.diffpyparset import DiffpyStructureParSet
+
+    if DiffpyStructureParSet.can_adapt(structure):
+        return DiffpyStructureParSet(name, structure)
+
+    from diffpy.cmistructure.objcrystparset import ObjCrystCrystalParSet
+
+    if ObjCrystCrystalParSet.can_adapt(structure):
+        return ObjCrystCrystalParSet(name, structure)
+
+    from diffpy.cmistructure.objcrystparset import ObjCrystMoleculeParSet
+
+    if ObjCrystMoleculeParSet.can_adapt(structure):
+        return ObjCrystMoleculeParSet(name, structure)
+
+    from diffpy.cmistructure.cctbxparset import CCTBXCrystalParSet
+
+    if CCTBXCrystalParSet.can_adapt(structure):
+        return CCTBXCrystalParSet(name, structure)
+
+    raise TypeError("Unadaptable structure format")
+
+
 # silence the pyflakes syntax checker
 assert __version__ or True