From 1c4f0dca4cc9da6a21b6a4484dbaeb28fb086ac7 Mon Sep 17 00:00:00 2001
From: jdsteve2 <jdsteve2@illinois.edu>
Date: Mon, 18 May 2020 21:05:56 -0500
Subject: [PATCH] remove compute_sccs and corresponding test (moved to pytools)

---
 loopy/tools.py    | 59 -----------------------------------------------
 test/test_misc.py | 45 ------------------------------------
 2 files changed, 104 deletions(-)

diff --git a/loopy/tools.py b/loopy/tools.py
index f7e9997c1..a1cd5e108 100644
--- a/loopy/tools.py
+++ b/loopy/tools.py
@@ -355,65 +355,6 @@ def empty_aligned(shape, dtype, order='C', n=64):
 # }}}
 
 
-# {{{ compute SCCs with Tarjan's algorithm
-
-def compute_sccs(graph):
-    to_search = set(graph.keys())
-    visit_order = {}
-    scc_root = {}
-    sccs = []
-
-    while to_search:
-        top = next(iter(to_search))
-        call_stack = [(top, iter(graph[top]), None)]
-        visit_stack = []
-        visiting = set()
-
-        scc = []
-
-        while call_stack:
-            top, children, last_popped_child = call_stack.pop()
-
-            if top not in visiting:
-                # Unvisited: mark as visited, initialize SCC root.
-                count = len(visit_order)
-                visit_stack.append(top)
-                visit_order[top] = count
-                scc_root[top] = count
-                visiting.add(top)
-                to_search.discard(top)
-
-            # Returned from a recursion, update SCC.
-            if last_popped_child is not None:
-                scc_root[top] = min(
-                    scc_root[top],
-                    scc_root[last_popped_child])
-
-            for child in children:
-                if child not in visit_order:
-                    # Recurse.
-                    call_stack.append((top, children, child))
-                    call_stack.append((child, iter(graph[child]), None))
-                    break
-                if child in visiting:
-                    scc_root[top] = min(
-                        scc_root[top],
-                        visit_order[child])
-            else:
-                if scc_root[top] == visit_order[top]:
-                    scc = []
-                    while visit_stack[-1] != top:
-                        scc.append(visit_stack.pop())
-                    scc.append(visit_stack.pop())
-                    for item in scc:
-                        visiting.remove(item)
-                    sccs.append(scc)
-
-    return sccs
-
-# }}}
-
-
 # {{{ pickled container value
 
 class _PickledObject(object):
diff --git a/test/test_misc.py b/test/test_misc.py
index 258bbc35e..dc5045fe0 100644
--- a/test/test_misc.py
+++ b/test/test_misc.py
@@ -24,7 +24,6 @@ THE SOFTWARE.
 
 import six  # noqa
 import pytest
-from six.moves import range
 
 import sys
 
@@ -35,50 +34,6 @@ logger = logging.getLogger(__name__)
 from loopy.version import LOOPY_USE_LANGUAGE_VERSION_2018_2  # noqa
 
 
-def test_compute_sccs():
-    from pytools.graph import compute_sccs
-    import random
-
-    rng = random.Random(0)
-
-    def generate_random_graph(nnodes):
-        graph = dict((i, set()) for i in range(nnodes))
-        for i in range(nnodes):
-            for j in range(nnodes):
-                # Edge probability 2/n: Generates decently interesting inputs.
-                if rng.randint(0, nnodes - 1) <= 1:
-                    graph[i].add(j)
-        return graph
-
-    def verify_sccs(graph, sccs):
-        visited = set()
-
-        def visit(node):
-            if node in visited:
-                return []
-            else:
-                visited.add(node)
-                result = []
-                for child in graph[node]:
-                    result = result + visit(child)
-                return result + [node]
-
-        for scc in sccs:
-            scc = set(scc)
-            assert not scc & visited
-            # Check that starting from each element of the SCC results
-            # in the same set of reachable nodes.
-            for scc_root in scc:
-                visited.difference_update(scc)
-                result = visit(scc_root)
-                assert set(result) == scc, (set(result), scc)
-
-    for nnodes in range(10, 20):
-        for i in range(40):
-            graph = generate_random_graph(nnodes)
-            verify_sccs(graph, compute_sccs(graph))
-
-
 def test_SetTrie():
     from loopy.kernel.tools import SetTrie
 
-- 
GitLab