From f2cd3d7da094f57f9f7e285e4f9e177b86b63f0c Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Mon, 16 May 2016 17:32:29 -0500
Subject: [PATCH] Add affs_from_space

---
 doc/misc.rst      |  3 +++
 doc/reference.rst | 10 ++++++++--
 islpy/__init__.py | 30 ++++++++++++++++++++++++++++++
 test/test_isl.py  | 18 +++++++++++++++++-
 4 files changed, 58 insertions(+), 3 deletions(-)

diff --git a/doc/misc.rst b/doc/misc.rst
index db3d1d9..be06a5b 100644
--- a/doc/misc.rst
+++ b/doc/misc.rst
@@ -93,6 +93,9 @@ Version 2016.2
     This version is currently in development and can be obtained from
     islpy's version control.
 
+* Update for isl 0.17
+* Add :func:`make_zero_and_vars`
+
 Version 2016.1.1
 ----------------
 
diff --git a/doc/reference.rst b/doc/reference.rst
index ff24938..cfe351f 100644
--- a/doc/reference.rst
+++ b/doc/reference.rst
@@ -82,6 +82,14 @@ Error Reporting
 
 .. exception:: Error
 
+Convenience
+^^^^^^^^^^^
+
+.. autofunction:: make_zero_and_vars
+
+.. autofunction:: affs_from_space
+
+
 Lifetime Helpers
 ^^^^^^^^^^^^^^^^
 
@@ -279,8 +287,6 @@ Piecewise Quasi-Affine Expression
 .. autoclass:: PwAff
     :members:
 
-.. autofunction:: make_zero_and_vars
-
 Union of Piecewise Quasi-Affine Expressions
 -------------------------------------------
 
diff --git a/islpy/__init__.py b/islpy/__init__.py
index 8765acd..b96eebc 100644
--- a/islpy/__init__.py
+++ b/islpy/__init__.py
@@ -1226,6 +1226,36 @@ def make_zero_and_vars(set_vars, params=[], ctx=None):
         params = [s.strip() for s in params.split(",")]
 
     space = Space.create_from_names(ctx, set=set_vars, params=params)
+    return affs_from_space(space)
+
+
+def affs_from_space(space):
+    """
+    :return: a dictionary from variable names (in *set_vars* and *params*)
+        to :class:`PwAff` instances that represent each of the
+        variables *in*space*. They key '0' is also include and represents
+        a :class:`PwAff` zero constant.
+
+    .. versionadded:: 2016.2
+
+    This function is intended to make it relatively easy to construct sets
+    programmatically without resorting to string manipulation.
+
+    Usage example::
+
+        s = isl.Set("[n] -> {[i,j,k]: 0<=i,j,k<n}")
+        v = isl.affs_from_space(s.space)
+
+        myset = (
+                v[0].le_set(v["i"] + v["j"])
+                &
+                (v["i"] + v["j"]).lt_set(v["n"])
+                &
+                (v[0].le_set(v["i"]))
+                &
+                (v["i"].le_set(13 + v["n"]))
+                )
+    """
 
     result = {}
 
diff --git a/test/test_isl.py b/test/test_isl.py
index a414b99..991031b 100644
--- a/test/test_isl.py
+++ b/test/test_isl.py
@@ -254,7 +254,7 @@ def test_codegen():
     print(isl_ast_codegen(s))
 
 
-def test_set_building():
+def test_make_zero_and_vars():
     v = isl.make_zero_and_vars("i,j,k", "n")
 
     myset = (
@@ -270,6 +270,22 @@ def test_set_building():
     print(myset)
 
 
+def test_affs_from_space():
+    s = isl.Set("[n] -> {[i,j,k]: 0<=i,j,k<n}")
+    v = isl.affs_from_space(s.space)
+
+    myset = (
+            v[0].le_set(v["i"] + v["j"])
+            &
+            (v["i"] + v["j"]).lt_set(v["n"])
+            &
+            (v[0].le_set(v["i"]))
+            &
+            (v["i"].le_set(13 + v["n"]))
+            )
+
+    print(myset)
+
 if __name__ == "__main__":
     import sys
     if len(sys.argv) > 1:
-- 
GitLab