added checks for Gemm re: input aliasing. they do not all pass.

_test_tensor.py

@@ -647,6 +647,7 @@ class t_gemm(unittest.TestCase):
     def setUp(self):
         numpy.random.seed(44)
         _approx_eq.debug = 0
+        Gemm.debug = False
 
     @staticmethod
     def _gemm(z,a,x,y,b):
@@ -681,6 +682,7 @@ class t_gemm(unittest.TestCase):
         cmp_linker(copy(z), a, x, y, b, gof.link.PerformLinker)
 
     def test0a(self): 
+        Gemm.debug = True
         try:
             g = gemm([1.], 1., [1.], [1.], 1.)
         except ValueError, e:
@@ -723,5 +725,52 @@ class t_gemm(unittest.TestCase):
     def test12(self): self.cmp(self.rand(3,4), -1.0,
             self.rand(3,5), self.rand(5,4), -1.0)
 
+    def test_destroy_map0(self):
+        """test that only first input can be overwritten"""
+        Z = astensor(self.rand(2,2))
+        try:
+            gemm(Z, 1.0, Z, Z, 1.0)
+        except ValueError, e:
+            if e[0] == Gemm.E_z_uniq:
+                return
+        self.fail()
+    def test_destroy_map1(self):
+        """test that only first input can be overwritten"""
+        Z = astensor(self.rand(2,2))
+        A = astensor(self.rand(2,2))
+        try:
+            gemm(Z, 1.0, A, Z.T, 1.0)
+        except ValueError, e:
+            if e[0] == Gemm.E_z_uniq:
+                return
+        self.fail()
+    def test_destroy_map2(self):
+        """test that only first input can be overwritten"""
+        Z = astensor(self.rand(2,2))
+        A = astensor(self.rand(2,2))
+        try:
+            gemm(Z, 1.0, Z.T, A, 1.0)
+        except ValueError, e:
+            if e[0] == Gemm.E_z_uniq:
+                return
+        self.fail()
+    def test_destroy_map3(self):
+        """test that only first input can be overwritten"""
+        Z = astensor(self.rand(2,2))
+        A = astensor(self.rand(2,2))
+        try:
+            gemm(Z, 1.0, Z, A, 1.0)
+        except ValueError, e:
+            if e[0] == Gemm.E_z_uniq:
+                return
+        self.fail()
+
+    def test_destroy_map4(self):
+        """test that dot args can be aliased"""
+        Z = astensor(self.rand(2,2))
+        A = astensor(self.rand(2,2))
+        eval_outputs([gemm(Z, 1.0, A, A, 1.0)])
+        eval_outputs([gemm(Z, 1.0, A, A.T, 1.0)])
+
 if __name__ == '__main__':
     unittest.main()

tensor.py

@@ -367,11 +367,13 @@ class Gemm(_Op):
     nout=1
     E_rank = 'gemm only works for rank 2'
     E_scalar = 'gemm requires scalar argument'
+    E_z_uniq = 'argument z not unique in argument list'
+    debug = False
     def __init__(self, *args, **kwargs):
-        z, a, x, y, b = args
-        if z in args[1:]:
-            raise ValueError('argument z not unique in argument list', args)
         _Op.__init__(self, *args, **kwargs)
+        z, a, x, y, b = self.inputs
+        if z in self.inputs[1:]:
+            raise ValueError(Gemm.E_z_uniq, self.inputs)
     def destroy_map(self):
         return {self.out:[self.inputs[0]]}
     def propagate_broadcastable(self, bz, ba, bx, by, bb):