From 016d654f2dc8b61b15457f62eff1719c4881e6d2 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Fri, 4 Dec 2020 18:14:57 -0700
Subject: [PATCH 01/14] Added power to Jax backend and test

---
 tensornetwork/backends/jax/jax_backend.py      |  3 +++
 tensornetwork/backends/jax/jax_backend_test.py | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index d7417e8f3..038960ce3 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -874,3 +874,6 @@ def sign(self, tensor: Tensor) -> Tensor:
 
   def item(self, tensor):
     return tensor.item()
+
+  def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
+    return jnp.power(a,b)
\ No newline at end of file
diff --git a/tensornetwork/backends/jax/jax_backend_test.py b/tensornetwork/backends/jax/jax_backend_test.py
index 13c74247c..cc3246b57 100644
--- a/tensornetwork/backends/jax/jax_backend_test.py
+++ b/tensornetwork/backends/jax/jax_backend_test.py
@@ -974,6 +974,18 @@ def matvec_jax(vector, matrix):
       num_krylov_vecs=100,
       tol=0.0001)
 
+def test_power(dtype):
+  np.random.seed(10)
+  backend = jax_backend.JaxBackend()
+  tensor = np.random.rand(2, 3, 4)
+  a = backend.convert_to_tensor(tensor)
+  actual = backend.power(a, axis=(1, 2))
+  expected = np.power(a, axis=(1, 2))
+  np.testing.assert_allclose(expected, actual)
+
+  actual = backend.power(a, axis=(1, 2), keepdims=True)
+  expected = np.power(a, axis=(1, 2), keepdims=True)
+  np.testing.assert_allclose(expected, actual)
 
 def test_sum():
   np.random.seed(10)
@@ -1240,3 +1252,6 @@ def test_item(dtype):
   backend = jax_backend.JaxBackend()
   tensor = backend.randn((1,), dtype=dtype, seed=10)
   assert backend.item(tensor) == tensor.item()
+
+
+

From 62a06c0688a04a45fa80945c08f311eace398bda Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Fri, 4 Dec 2020 19:18:27 -0700
Subject: [PATCH 02/14] Added power function to the Jax backend and test.

---
 tensornetwork/backends/jax/jax_backend.py | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index 038960ce3..aa488bee8 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -876,4 +876,15 @@ def item(self, tensor):
     return tensor.item()
 
   def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
-    return jnp.power(a,b)
\ No newline at end of file
+    """
+    Returns power of tensor a to the value of b.
+    In the case b is a tensor, then the power is by element
+      with a as the base and b as the exponent.
+    In the case b is a scalar, then the power of each value in a
+      is raised to the exponent of b.
+
+    Args:
+      a: The tensor that contains the base.
+      b: The tensor that contains the exponent or a single scalar.
+    """
+    return jnp.power(a,b)

From 43952dde29765a0dfcd73c97b28914a55d9c7ad3 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Fri, 4 Dec 2020 20:13:21 -0700
Subject: [PATCH 03/14] Fixed white space error.

---
 tensornetwork/backends/jax/jax_backend.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index aa488bee8..68c4d9540 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -887,4 +887,4 @@ def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
       a: The tensor that contains the base.
       b: The tensor that contains the exponent or a single scalar.
     """
-    return jnp.power(a,b)
+    return jnp.power(a, b)

From b0f579e4634e3636793dd8b3f933ad14eb19b123 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sat, 5 Dec 2020 00:44:28 -0700
Subject: [PATCH 04/14] Re-made the power test function.

---
 .../backends/jax/jax_backend_test.py          | 29 +++++++++----------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/tensornetwork/backends/jax/jax_backend_test.py b/tensornetwork/backends/jax/jax_backend_test.py
index cc3246b57..3c8926f64 100644
--- a/tensornetwork/backends/jax/jax_backend_test.py
+++ b/tensornetwork/backends/jax/jax_backend_test.py
@@ -974,19 +974,6 @@ def matvec_jax(vector, matrix):
       num_krylov_vecs=100,
       tol=0.0001)
 
-def test_power(dtype):
-  np.random.seed(10)
-  backend = jax_backend.JaxBackend()
-  tensor = np.random.rand(2, 3, 4)
-  a = backend.convert_to_tensor(tensor)
-  actual = backend.power(a, axis=(1, 2))
-  expected = np.power(a, axis=(1, 2))
-  np.testing.assert_allclose(expected, actual)
-
-  actual = backend.power(a, axis=(1, 2), keepdims=True)
-  expected = np.power(a, axis=(1, 2), keepdims=True)
-  np.testing.assert_allclose(expected, actual)
-
 def test_sum():
   np.random.seed(10)
   backend = jax_backend.JaxBackend()
@@ -1253,5 +1240,17 @@ def test_item(dtype):
   tensor = backend.randn((1,), dtype=dtype, seed=10)
   assert backend.item(tensor) == tensor.item()
 
-
-
+@pytest.mark.parametrize("dtype", tf_dtypes)
+def test_power(dtype):
+  shape = (4, 3, 2)
+  backend = jax_backend.JaxBackend()
+  base_tensor = backend.randn(shape, dtype=dtype, seed=10)
+  power_tensor = backend.randn(shape, dtype=dtype, seed=10)
+  actual = backend.power(base_tensor, power_tensor)
+  expected = tf.math.pow(base_tensor, power_tensor)
+  np.testing.assert_allclose(expected, actual)
+  
+  power = np.random.rand(1)[0]
+  actual = backend.power(base_tensor, power)
+  expected = tf.math.pow(base_tensor, power)
+  np.testing.assert_allclose(expected, actual)
\ No newline at end of file

From e9f9869942b9ceb58caf5552e6e7290be0a958a7 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sat, 5 Dec 2020 00:49:59 -0700
Subject: [PATCH 05/14] Fixed typo

---
 tensornetwork/backends/jax/jax_backend_test.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tensornetwork/backends/jax/jax_backend_test.py b/tensornetwork/backends/jax/jax_backend_test.py
index 3c8926f64..02b41c05e 100644
--- a/tensornetwork/backends/jax/jax_backend_test.py
+++ b/tensornetwork/backends/jax/jax_backend_test.py
@@ -1240,7 +1240,7 @@ def test_item(dtype):
   tensor = backend.randn((1,), dtype=dtype, seed=10)
   assert backend.item(tensor) == tensor.item()
 
-@pytest.mark.parametrize("dtype", tf_dtypes)
+@pytest.mark.parametrize("dtype", np_dtypes)
 def test_power(dtype):
   shape = (4, 3, 2)
   backend = jax_backend.JaxBackend()
@@ -1249,7 +1249,7 @@ def test_power(dtype):
   actual = backend.power(base_tensor, power_tensor)
   expected = tf.math.pow(base_tensor, power_tensor)
   np.testing.assert_allclose(expected, actual)
-  
+
   power = np.random.rand(1)[0]
   actual = backend.power(base_tensor, power)
   expected = tf.math.pow(base_tensor, power)

From 9e16a9faacbfc318a497f8dadf130b4ef0ca32c1 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sat, 5 Dec 2020 01:30:23 -0700
Subject: [PATCH 06/14] Testing out numpy square.

---
 tensornetwork/backends/jax/jax_backend.py      | 2 +-
 tensornetwork/backends/jax/jax_backend_test.py | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index 68c4d9540..f3d7c04a2 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -887,4 +887,4 @@ def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
       a: The tensor that contains the base.
       b: The tensor that contains the exponent or a single scalar.
     """
-    return jnp.power(a, b)
+    return jnp.square(a, b)
diff --git a/tensornetwork/backends/jax/jax_backend_test.py b/tensornetwork/backends/jax/jax_backend_test.py
index 02b41c05e..6050c6271 100644
--- a/tensornetwork/backends/jax/jax_backend_test.py
+++ b/tensornetwork/backends/jax/jax_backend_test.py
@@ -1253,4 +1253,5 @@ def test_power(dtype):
   power = np.random.rand(1)[0]
   actual = backend.power(base_tensor, power)
   expected = tf.math.pow(base_tensor, power)
-  np.testing.assert_allclose(expected, actual)
\ No newline at end of file
+  np.testing.assert_allclose(expected, actual)
+  
\ No newline at end of file

From 81b4d8b6faeeb251e3ec8ef040c2ba174d074d4d Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sat, 5 Dec 2020 02:09:54 -0700
Subject: [PATCH 07/14] Fixed issues with the assertion in test, should work
 now.

---
 tensornetwork/backends/jax/jax_backend.py      | 4 ++--
 tensornetwork/backends/jax/jax_backend_test.py | 5 ++---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index f3d7c04a2..2ef092eda 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -875,7 +875,7 @@ def sign(self, tensor: Tensor) -> Tensor:
   def item(self, tensor):
     return tensor.item()
 
-  def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
+  def power(self, a: Tensor, b: Union[Tensor, int]) -> Tensor:
     """
     Returns power of tensor a to the value of b.
     In the case b is a tensor, then the power is by element
@@ -887,4 +887,4 @@ def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
       a: The tensor that contains the base.
       b: The tensor that contains the exponent or a single scalar.
     """
-    return jnp.square(a, b)
+    return jnp.power(a, b)
diff --git a/tensornetwork/backends/jax/jax_backend_test.py b/tensornetwork/backends/jax/jax_backend_test.py
index 6050c6271..87b270e02 100644
--- a/tensornetwork/backends/jax/jax_backend_test.py
+++ b/tensornetwork/backends/jax/jax_backend_test.py
@@ -1247,11 +1247,10 @@ def test_power(dtype):
   base_tensor = backend.randn(shape, dtype=dtype, seed=10)
   power_tensor = backend.randn(shape, dtype=dtype, seed=10)
   actual = backend.power(base_tensor, power_tensor)
-  expected = tf.math.pow(base_tensor, power_tensor)
+  expected = jax.numpy.power(base_tensor, power_tensor)
   np.testing.assert_allclose(expected, actual)
 
   power = np.random.rand(1)[0]
   actual = backend.power(base_tensor, power)
-  expected = tf.math.pow(base_tensor, power)
+  expected = jax.numpy.power(base_tensor, power)
   np.testing.assert_allclose(expected, actual)
-  
\ No newline at end of file

From 195f69198d4cc1a626ca43bba07bab05ece994fd Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sat, 5 Dec 2020 23:57:51 -0700
Subject: [PATCH 08/14] Added NotImplementedError function and it's respective
 test for Cholskey decomposition.

---
 tensornetwork/backends/abstract_backend.py | 4 ++++
 tensornetwork/backends/backend_test.py     | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/tensornetwork/backends/abstract_backend.py b/tensornetwork/backends/abstract_backend.py
index 4e57d366e..e72d5a14f 100644
--- a/tensornetwork/backends/abstract_backend.py
+++ b/tensornetwork/backends/abstract_backend.py
@@ -1022,3 +1022,7 @@ def item(self, tensor) -> Union[float, int, complex]:
       The value in tensor.
     """
     raise NotImplementedError("Backend {self.name} has not implemented item")
+
+  def chsky(self, tensor: Tensor, pivot_axis: int = -1, non_negative_diagonal: bool = False) -> Tuple[Tensor, Tensor]:
+    """Computes the Cholskey decomposition of a tensor."""
+    raise NotImplementedError("Backend '{}' has not implemented chsky.".format(self.name))
diff --git a/tensornetwork/backends/backend_test.py b/tensornetwork/backends/backend_test.py
index 6230361a1..2aef64732 100644
--- a/tensornetwork/backends/backend_test.py
+++ b/tensornetwork/backends/backend_test.py
@@ -193,6 +193,12 @@ def test_abstract_backend_qr_decompositon_not_implemented():
     backend.qr(np.ones((2, 2)), 0)
 
 
+def test_abstract_backend_chsky_decompositon_not_implemented():
+  backend = AbstractBackend()
+  with pytest.raises(NotImplementedError):
+    backend.chsky(np.ones((2, 2)), 0)
+
+
 def test_abstract_backend_rq_decompositon_not_implemented():
   backend = AbstractBackend()
   with pytest.raises(NotImplementedError):

From 737f07149cbb3cc09399d30b3035f02171954a56 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sun, 6 Dec 2020 00:23:20 -0700
Subject: [PATCH 09/14] Fixed line too long error

---
 tensornetwork/backends/abstract_backend.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tensornetwork/backends/abstract_backend.py b/tensornetwork/backends/abstract_backend.py
index e72d5a14f..31ff08921 100644
--- a/tensornetwork/backends/abstract_backend.py
+++ b/tensornetwork/backends/abstract_backend.py
@@ -1023,6 +1023,9 @@ def item(self, tensor) -> Union[float, int, complex]:
     """
     raise NotImplementedError("Backend {self.name} has not implemented item")
 
-  def chsky(self, tensor: Tensor, pivot_axis: int = -1, non_negative_diagonal: bool = False) -> Tuple[Tensor, Tensor]:
+  def chsky(self, tensor: Tensor, 
+            pivot_axis: int = -1, 
+            non_negative_diagonal: bool = False) -> 
+            Tuple[Tensor, Tensor]:
     """Computes the Cholskey decomposition of a tensor."""
     raise NotImplementedError("Backend '{}' has not implemented chsky.".format(self.name))

From 0fbe8fb3cb5a94b219280f17e65abbfebccdb83f Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sun, 6 Dec 2020 00:59:34 -0700
Subject: [PATCH 10/14] Removing changes for different branches.

---
 tensornetwork/backends/jax/jax_backend.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index 2ef092eda..d444653b1 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -877,7 +877,7 @@ def item(self, tensor):
 
   def power(self, a: Tensor, b: Union[Tensor, int]) -> Tensor:
     """
-    Returns power of tensor a to the value of b.
+    Returns the power of tensor a to the value of b.
     In the case b is a tensor, then the power is by element
       with a as the base and b as the exponent.
     In the case b is a scalar, then the power of each value in a

From 8c376566cc1ab9e8151bed64edbd2fc538a802b2 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sun, 6 Dec 2020 01:38:44 -0700
Subject: [PATCH 11/14] Revert "Fixed issues with the assertion in test, should
 work now."

This reverts commit 81b4d8b6faeeb251e3ec8ef040c2ba174d074d4d.
---
 tensornetwork/backends/jax/jax_backend.py      | 4 ++--
 tensornetwork/backends/jax/jax_backend_test.py | 5 +++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index d444653b1..3b6ed659a 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -875,7 +875,7 @@ def sign(self, tensor: Tensor) -> Tensor:
   def item(self, tensor):
     return tensor.item()
 
-  def power(self, a: Tensor, b: Union[Tensor, int]) -> Tensor:
+  def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
     """
     Returns the power of tensor a to the value of b.
     In the case b is a tensor, then the power is by element
@@ -887,4 +887,4 @@ def power(self, a: Tensor, b: Union[Tensor, int]) -> Tensor:
       a: The tensor that contains the base.
       b: The tensor that contains the exponent or a single scalar.
     """
-    return jnp.power(a, b)
+    return jnp.square(a, b)
diff --git a/tensornetwork/backends/jax/jax_backend_test.py b/tensornetwork/backends/jax/jax_backend_test.py
index 87b270e02..6050c6271 100644
--- a/tensornetwork/backends/jax/jax_backend_test.py
+++ b/tensornetwork/backends/jax/jax_backend_test.py
@@ -1247,10 +1247,11 @@ def test_power(dtype):
   base_tensor = backend.randn(shape, dtype=dtype, seed=10)
   power_tensor = backend.randn(shape, dtype=dtype, seed=10)
   actual = backend.power(base_tensor, power_tensor)
-  expected = jax.numpy.power(base_tensor, power_tensor)
+  expected = tf.math.pow(base_tensor, power_tensor)
   np.testing.assert_allclose(expected, actual)
 
   power = np.random.rand(1)[0]
   actual = backend.power(base_tensor, power)
-  expected = jax.numpy.power(base_tensor, power)
+  expected = tf.math.pow(base_tensor, power)
   np.testing.assert_allclose(expected, actual)
+  
\ No newline at end of file

From 06c579aedb65c9447725533fe6177ab65a84d14c Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sun, 6 Dec 2020 12:36:35 -0700
Subject: [PATCH 12/14] Spilt up cholesky and jax modifications to diferent
 branches.

---
 tensornetwork/backends/abstract_backend.py | 7 -------
 tensornetwork/backends/backend_test.py     | 6 ------
 tensornetwork/backends/jax/jax_backend.py  | 2 +-
 3 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/tensornetwork/backends/abstract_backend.py b/tensornetwork/backends/abstract_backend.py
index 31ff08921..4e57d366e 100644
--- a/tensornetwork/backends/abstract_backend.py
+++ b/tensornetwork/backends/abstract_backend.py
@@ -1022,10 +1022,3 @@ def item(self, tensor) -> Union[float, int, complex]:
       The value in tensor.
     """
     raise NotImplementedError("Backend {self.name} has not implemented item")
-
-  def chsky(self, tensor: Tensor, 
-            pivot_axis: int = -1, 
-            non_negative_diagonal: bool = False) -> 
-            Tuple[Tensor, Tensor]:
-    """Computes the Cholskey decomposition of a tensor."""
-    raise NotImplementedError("Backend '{}' has not implemented chsky.".format(self.name))
diff --git a/tensornetwork/backends/backend_test.py b/tensornetwork/backends/backend_test.py
index 2aef64732..6230361a1 100644
--- a/tensornetwork/backends/backend_test.py
+++ b/tensornetwork/backends/backend_test.py
@@ -193,12 +193,6 @@ def test_abstract_backend_qr_decompositon_not_implemented():
     backend.qr(np.ones((2, 2)), 0)
 
 
-def test_abstract_backend_chsky_decompositon_not_implemented():
-  backend = AbstractBackend()
-  with pytest.raises(NotImplementedError):
-    backend.chsky(np.ones((2, 2)), 0)
-
-
 def test_abstract_backend_rq_decompositon_not_implemented():
   backend = AbstractBackend()
   with pytest.raises(NotImplementedError):
diff --git a/tensornetwork/backends/jax/jax_backend.py b/tensornetwork/backends/jax/jax_backend.py
index 3b6ed659a..9f5eb9843 100644
--- a/tensornetwork/backends/jax/jax_backend.py
+++ b/tensornetwork/backends/jax/jax_backend.py
@@ -887,4 +887,4 @@ def power(self, a: Tensor, b: Union[Tensor, float]) -> Tensor:
       a: The tensor that contains the base.
       b: The tensor that contains the exponent or a single scalar.
     """
-    return jnp.square(a, b)
+    return jnp.power(a, b)

From 3624ccf270b44bfcaffceab9d421dc341b601dd8 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Sun, 6 Dec 2020 13:18:14 -0700
Subject: [PATCH 13/14] Fixed wrong power function call

---
 tensornetwork/backends/jax/jax_backend_test.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tensornetwork/backends/jax/jax_backend_test.py b/tensornetwork/backends/jax/jax_backend_test.py
index 6050c6271..615bba2e6 100644
--- a/tensornetwork/backends/jax/jax_backend_test.py
+++ b/tensornetwork/backends/jax/jax_backend_test.py
@@ -1247,11 +1247,11 @@ def test_power(dtype):
   base_tensor = backend.randn(shape, dtype=dtype, seed=10)
   power_tensor = backend.randn(shape, dtype=dtype, seed=10)
   actual = backend.power(base_tensor, power_tensor)
-  expected = tf.math.pow(base_tensor, power_tensor)
+  expected = jax.numpy.power(base_tensor, power_tensor)
   np.testing.assert_allclose(expected, actual)
 
   power = np.random.rand(1)[0]
   actual = backend.power(base_tensor, power)
-  expected = tf.math.pow(base_tensor, power)
+  expected = jax.numpy.power(base_tensor, power)
   np.testing.assert_allclose(expected, actual)
   
\ No newline at end of file

From aefd843178342f67f2fd7b3af571681db54b33a6 Mon Sep 17 00:00:00 2001
From: LuiGiovanni <giovanni.lopez3523@gmail.com>
Date: Fri, 18 Dec 2020 13:47:03 -0700
Subject: [PATCH 14/14] Added power function for Pytorch and symmetric with
 their tests

---
 tensornetwork/backends/pytorch/pytorch_backend.py  | 14 ++++++++++++++
 .../backends/pytorch/pytorch_backend_test.py       | 12 ++++++++++++
 .../backends/symmetric/symmetric_backend.py        | 14 ++++++++++++++
 .../backends/symmetric/symmetric_backend_test.py   | 13 +++++++++++++
 4 files changed, 53 insertions(+)

diff --git a/tensornetwork/backends/pytorch/pytorch_backend.py b/tensornetwork/backends/pytorch/pytorch_backend.py
index 8467fac39..fb3ae238a 100644
--- a/tensornetwork/backends/pytorch/pytorch_backend.py
+++ b/tensornetwork/backends/pytorch/pytorch_backend.py
@@ -475,3 +475,17 @@ def sign(self, tensor: Tensor) -> Tensor:
   
   def item(self, tensor):
     return tensor.item()
+
+  def power(self, a: Tensor, b: Tensor) -> Tensor:
+    """
+    Returns the power of tensor a to the value of b.
+    In the case b is a tensor, then the power is by element
+      with a as the base and b as the exponent.
+    In the case b is a scalar, then the power of each value in a
+      is raised to the exponent of b.
+
+    Args:
+      a: The tensor that contains the base.
+      b: The tensor that contains the exponent or a single scalar.
+    """
+    return a ** b
diff --git a/tensornetwork/backends/pytorch/pytorch_backend_test.py b/tensornetwork/backends/pytorch/pytorch_backend_test.py
index f44aed5c6..82a3e6356 100644
--- a/tensornetwork/backends/pytorch/pytorch_backend_test.py
+++ b/tensornetwork/backends/pytorch/pytorch_backend_test.py
@@ -566,6 +566,18 @@ def test_matmul():
   np.testing.assert_allclose(expected, actual)
 
 
+def test_power():
+  np.random.seed(10)
+  backend = pytorch_backend.PyTorchBackend()
+  t1 = np.random.rand(10, 2, 3)
+  t2 = np.random.rand(10, 3, 4)
+  a = backend.convert_to_tensor(t1)
+  b = backend.convert_to_tensor(t2)
+  actual = backend.power(a, b)
+  expected = np.power(t1, t2)
+  np.testing.assert_allclose(expected, actual)
+
+
 @pytest.mark.parametrize("dtype", torch_randn_dtypes)
 @pytest.mark.parametrize("offset", range(-2, 2))
 @pytest.mark.parametrize("axis1", [-2, 0])
diff --git a/tensornetwork/backends/symmetric/symmetric_backend.py b/tensornetwork/backends/symmetric/symmetric_backend.py
index 9e55bc694..1b1c517e3 100644
--- a/tensornetwork/backends/symmetric/symmetric_backend.py
+++ b/tensornetwork/backends/symmetric/symmetric_backend.py
@@ -689,3 +689,17 @@ def matmul(self, tensor1: Tensor, tensor2: Tensor):
     if (tensor1.ndim != 2) or (tensor2.ndim != 2):
       raise ValueError("inputs to `matmul` have to be matrices")
     return tensor1 @ tensor2
+
+  def power(self, a: Tensor, b: Tensor) -> Tensor:
+    """
+    Returns the power of tensor a to the value of b.
+    In the case b is a tensor, then the power is by element
+      with a as the base and b as the exponent.
+    In the case b is a scalar, then the power of each value in a
+      is raised to the exponent of b.
+
+    Args:
+      a: The tensor that contains the base.
+      b: The tensor that contains the exponent or a single scalar.
+    """
+    return a ** b
diff --git a/tensornetwork/backends/symmetric/symmetric_backend_test.py b/tensornetwork/backends/symmetric/symmetric_backend_test.py
index a8b78051e..f38d8bdc5 100644
--- a/tensornetwork/backends/symmetric/symmetric_backend_test.py
+++ b/tensornetwork/backends/symmetric/symmetric_backend_test.py
@@ -609,6 +609,19 @@ def test_addition_raises(R, dtype, num_charges):
     backend.addition(a, c)
 
 
+@pytest.mark.parametrize("dtype", np_dtypes)
+@pytest.mark.parametrize("num_charges", [1, 2])
+def test_power(dtype, num_charges):
+  np.random.seed(10)
+  R = 4
+  backend = symmetric_backend.SymmetricBackend()
+  a = get_tensor(R, num_charges, dtype)
+  b = BlockSparseTensor.random(a.sparse_shape)
+  expected = np.power(a.data, b.data)
+  actual = backend.power(a.data, b.data)
+  np.testing.assert_allclose(expected, actual)
+
+
 @pytest.mark.parametrize("dtype", np_dtypes)
 @pytest.mark.parametrize("R", [2, 3, 4, 5])
 @pytest.mark.parametrize("num_charges", [1, 2])