Implements a reindexing transformation

.github/workflows/ci.yml

@@ -104,6 +104,20 @@ jobs:
                 ( test_py_project )
                 ( test_py_project )
 
+    pytest_with_barvinok:
+        name: Conda Pytest with Barvinok
+        runs-on: ubuntu-latest
+        steps:
+        -   uses: actions/checkout@v2
+        -   name: "Main Script"
+            run: |
+                CONDA_ENVIRONMENT=.test-conda-env-py3.yml
+                echo "- barvinok" >> "$CONDA_ENVIRONMENT"
+                curl -L -O https://tiker.net/ci-support-v0
+                . ./ci-support-v0
+                build_py_project_in_conda_env
+                test_py_project
+
     examples:
         name: Conda Examples
         runs-on: ubuntu-latest

doc/misc.rst

@@ -456,6 +456,13 @@ Here's a Bibtex entry for your convenience::
        doi = "{10.1145/2627373.2627387}",
     }
 
+References
+==========
+
+.. [Seghir_2006] Seghir and Loechner, Proceedings of the 2006 International
+    Conference on Compilers, Architecture and Synthesis for Embedded systems,
+    `(DOI) <https://doi.org/10.1145/1176760.1176771>`__
+
 Getting help
 ============
 

doc/ref_transform.rst

@@ -54,6 +54,8 @@ Influencing data access
 
 .. autofunction:: allocate_temporaries_for_base_storage
 
+.. automodule:: loopy.transform.reindex
+
 Padding Data
 ------------
 

loopy/__init__.py

@@ -108,6 +108,8 @@
 from loopy.transform.fusion import fuse_kernels
 from loopy.transform.concatenate import concatenate_arrays
 
+from loopy.transform.reindex import reindex_temporary_using_seghir_loechner_scheme
+
 from loopy.transform.arithmetic import (
         fold_constants,
         collect_common_factors_on_increment)
@@ -239,6 +241,8 @@
 
         "fold_constants", "collect_common_factors_on_increment",
 
+        "reindex_temporary_using_seghir_loechner_scheme",
+
         "split_array_axis", "split_array_dim", "split_arg_axis",
         "find_padding_multiple", "add_padding",
 

loopy/symbolic.py

@@ -24,7 +24,7 @@
 """
 
 
-from typing import ClassVar, Tuple
+from typing import ClassVar, Tuple, Union
 from functools import reduce, cached_property
 from sys import intern
 import re
@@ -69,6 +69,7 @@
 from loopy.diagnostic import LoopyError
 from loopy.diagnostic import (ExpressionToAffineConversionError,
                               UnableToDetermineAccessRangeError)
+from loopy.typing import ExpressionT
 
 
 __doc__ = """
@@ -2792,4 +2793,29 @@ def is_tuple_of_expressions_equal(a, b):
 
 # }}}
 
+
+def _is_isl_set_universe(isl_set: Union[isl.BasicSet, isl.Set]):
+    if isinstance(isl_set, isl.BasicSet):
+        return isl_set.is_universe()
+    else:
+        assert isinstance(isl_set, isl.Set)
+        return isl_set.complement().is_empty()
+
+
+def pw_qpolynomial_to_expr(pw_qpoly: isl.PwQPolynomial
+                           ) -> ExpressionT:
+    from pymbolic.primitives import If
+
+    result = 0
+
+    for bset, qpoly in reversed(pw_qpoly.get_pieces()):
+        if _is_isl_set_universe(bset):
+            result = qpolynomial_to_expr(qpoly)
+        else:
+            result = If(set_to_cond_expr(bset),
+                        qpolynomial_to_expr(qpoly),
+                        result)
+
+    return result
+
 # vim: foldmethod=marker