Merge pull request #66 from undingen/spectral_norm

Add (modified) spectral_norm millibenchmark from the language shootout.

millibenchmarks/spectral_norm.py

+# The Computer Language Benchmarks Game
+# http://benchmarksgame.alioth.debian.org/
+#
+# Contributed by Sebastien Loisel
+# Fixed by Isaac Gouy
+# Sped up by Josh Goldfoot
+# Dirtily sped up by Simon Descarpentries
+# Used list comprehension by Vadim Zelenin
+# 2to3
+
+from math      import sqrt
+from sys       import argv
+
+# pyston does not yet support enumerate
+def _enumerate(sequence):
+    n = 0
+    rtn = []
+    for elem in sequence:
+        rtn.append((n, elem))
+        n += 1
+    return rtn
+
+
+def eval_A(i, j):
+    ij = i+j
+    return 1.0 / (ij * (ij + 1) / 2 + i + 1)
+
+
+def eval_A_times_u(u):
+    local_eval_A = eval_A
+
+    return [ sum([ local_eval_A(i, j) * u_j
+                   for j, u_j in _enumerate(u)
+                 ]
+                )
+             for i in range(len(u))
+           ]
+
+
+def eval_At_times_u(u):
+    local_eval_A = eval_A
+
+    return [ sum([ local_eval_A(j, i) * u_j
+                   for j, u_j in _enumerate(u)
+                 ]
+                )
+             for i in range(len(u))
+           ]
+
+
+def eval_AtA_times_u(u):
+    return eval_At_times_u(eval_A_times_u(u))
+
+
+def main():
+    #n = int(argv[1])
+    n = 1000 # when pyston gets faster we should increase this
+    u = [1] * n
+    local_eval_AtA_times_u = eval_AtA_times_u
+
+    for dummy in range(10):
+        v = local_eval_AtA_times_u(u)
+        u = local_eval_AtA_times_u(v)
+
+    vBv = vv = 0
+
+    for ue, ve in zip(u, v):
+        vBv += ue * ve
+        vv  += ve * ve
+
+    print("%0.9f" % (sqrt(vBv/vv)))
+
+main()

src/runtime/builtin_modules/builtins.cpp

@@ -310,6 +310,22 @@ Box* map2(Box* f, Box* container) {
     return rtn;
 }
 
+Box* zip2(Box* container1, Box* container2) {
+    BoxedList* rtn = new BoxedList();
+
+    llvm::iterator_range<BoxIterator> range1 = container1->pyElements();
+    llvm::iterator_range<BoxIterator> range2 = container2->pyElements();
+
+    BoxIterator it1 = range1.begin();
+    BoxIterator it2 = range2.begin();
+
+    for (; it1 != range1.end() && it2 != range2.end(); ++it1, ++it2) {
+        BoxedTuple::GCVector elts{ *it1, *it2 };
+        listAppendInternal(rtn, new BoxedTuple(std::move(elts)));
+    }
+    return rtn;
+}
+
 extern "C" const ObjectFlavor notimplemented_flavor(&boxGCHandler, NULL);
 BoxedClass* notimplemented_cls;
 BoxedModule* builtins_module;
@@ -459,6 +475,7 @@ void setupBuiltins() {
     builtins_module->giveAttr("open", open_obj);
 
     builtins_module->giveAttr("map", new BoxedFunction(boxRTFunction((void*)map2, LIST, 2, false)));
+    builtins_module->giveAttr("zip", new BoxedFunction(boxRTFunction((void*)zip2, LIST, 2, false)));
 
     builtins_module->setattr("str", str_cls, NULL, NULL);
     builtins_module->setattr("int", int_cls, NULL, NULL);

test/tests/builtins.py

@@ -26,3 +26,5 @@ class C(object):
         return self
 
 print sum([C(1), C(2), C(3)], C(4)).n
+
+print zip([1, 2, 3, 0], ["one", "two", "three"])