From ffa892d42affdc4510f15531e44aba4b5697b669 Mon Sep 17 00:00:00 2001
From: minalkharat-cmd <minalkharat@gmail.com>
Date: Sat, 31 Jan 2026 13:33:18 +0530
Subject: [PATCH 1/2] Add missing acos_ in-place function and improve
 documentation

- Add missing in-place version acos_() function
- Improve documentation with detailed docstrings
- Add usage examples in docstrings
- Maintain compatibility with existing acos() function

Part of completing issue #883

Signed-off-by: minalkharat-cmd <minalkharat@gmail.com>
---
 src/flag_gems/ops/acos.py | 56 +++++++++++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 5 deletions(-)

diff --git a/src/flag_gems/ops/acos.py b/src/flag_gems/ops/acos.py
index c34d3a420..1ec96cf38 100644
--- a/src/flag_gems/ops/acos.py
+++ b/src/flag_gems/ops/acos.py
@@ -12,11 +12,57 @@
 @pointwise_dynamic(promotion_methods=[(0, "INT_TO_FLOAT")])
 @triton.jit()
 def acos_kernel(x):
-    # TODO: use flag_gems.utils.tl_extra_shim help apis
-    return _acos(x.to(tl.float32))
+        """
+            Compute arccos(x) for input x.
+
+                    The arccos function returns values in the range [0, π] for input values in [-1, 1].
+
+                            Args:
+                                    x: Input tensor (will be converted to float32 for computation)
+
+                                                Returns:
+                                                        Tensor with arccos(x) computed element-wise
+                                                            """
+        return _acos(x.to(tl.float32))
 
 
 def acos(x):
-    logger.debug("GEMS ACOS FORWARD")
-    y = acos_kernel(x)
-    return y
+        """
+            Computes the inverse cosine (arccos) of each element in input.
+
+                    Args:
+                            x (Tensor): Input tensor with values in [-1, 1]
+
+                                        Returns:
+                                                Tensor: Output tensor with values in [0, π]
+
+                                                            Example:
+                                                                    >>> x = torch.tensor([0.0, 0.5, 1.0])
+                                                                            >>> torch.acos(x)
+                                                                                    tensor([1.5708, 1.0472, 0.0000])
+                                                                                        """
+        logger.debug("GEMS ACOS FORWARD")
+        y = acos_kernel(x)
+        return y
+
+
+def acos_(x):
+        """
+            In-place version of acos.
+
+                    Computes the inverse cosine of each element in input, modifying the tensor in-place.
+
+                            Args:
+                                    x (Tensor): Input tensor with values in [-1, 1] (modified in-place)
+
+                                                Returns:
+                                                        Tensor: The modified input tensor
+
+                                                                    Example:
+                                                                            >>> x = torch.tensor([0.0, 0.5, 1.0])
+                                                                                    >>> torch.acos_(x)
+                                                                                            tensor([1.5708, 1.0472, 0.0000])
+                                                                                                """
+        logger.debug("GEMS ACOS_ INPLACE")
+        acos_kernel(x, out0=x)
+        return x

From a501535dcd57869446b1694cb81d5f2ff8c54dce Mon Sep 17 00:00:00 2001
From: minalkharat-cmd <minalkharat@gmail.com>
Date: Sat, 31 Jan 2026 14:08:16 +0530
Subject: [PATCH 2/2] Add tests, benchmarks and export acos_ operator -
 Completes #883

---
 benchmark/test_unary_pointwise_perf.py |  1 +
 src/flag_gems/ops/__init__.py          |  3 ++-
 tests/test_unary_pointwise_ops.py      | 15 +++++++++++++++
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/benchmark/test_unary_pointwise_perf.py b/benchmark/test_unary_pointwise_perf.py
index 8038cf680..b5d74eb3b 100644
--- a/benchmark/test_unary_pointwise_perf.py
+++ b/benchmark/test_unary_pointwise_perf.py
@@ -124,6 +124,7 @@ def test_general_unary_pointwise_perf(op_name, torch_op, dtypes):
     ("tan_", torch.tan_, FLOAT_DTYPES),
     ("tanh_", torch.tanh_, FLOAT_DTYPES),
     ("atan_", torch.atan_, FLOAT_DTYPES),
+    ("acos_", torch.acos_, FLOAT_DTYPES),
     # Bitwise operations
     ("bitwise_not_", lambda a: a.bitwise_not_(), INT_DTYPES),
 ]
diff --git a/src/flag_gems/ops/__init__.py b/src/flag_gems/ops/__init__.py
index 3cd2c8b1f..64aaa3a9a 100755
--- a/src/flag_gems/ops/__init__.py
+++ b/src/flag_gems/ops/__init__.py
@@ -1,5 +1,5 @@
 from flag_gems.ops.abs import abs, abs_
-from flag_gems.ops.acos import acos
+from flag_gems.ops.acos import acos, acos_
 from flag_gems.ops.add import add, add_
 from flag_gems.ops.addcdiv import addcdiv
 from flag_gems.ops.addcmul import addcmul
@@ -243,6 +243,7 @@
     "abs",
     "abs_",
     "acos",
+    "acos_",
     "add",
     "add_",
     "addcdiv",
diff --git a/tests/test_unary_pointwise_ops.py b/tests/test_unary_pointwise_ops.py
index 0ff8c874d..61fe8a5e7 100644
--- a/tests/test_unary_pointwise_ops.py
+++ b/tests/test_unary_pointwise_ops.py
@@ -72,6 +72,21 @@ def test_accuracy_acos(shape, dtype):
     gems_assert_close(res_out, ref_out, dtype, True)
 
 
+@pytest.mark.inplace
+@pytest.mark.acos_
+@pytest.mark.parametrize("shape", POINTWISE_SHAPES)
+@pytest.mark.parametrize("dtype", FLOAT_DTYPES)
+def test_accuracy_acos_(shape, dtype):
+    inp = torch.randn(shape, dtype=dtype, device=flag_gems.device)
+    ref_inp = to_reference(inp.clone(), True)
+
+    ref_out = torch.acos_(ref_inp)
+    with flag_gems.use_gems():
+        res_out = torch.acos_(inp)
+
+    gems_assert_close(res_out, ref_out, dtype, True)
+
+
 @pytest.mark.angle
 @pytest.mark.parametrize("shape", POINTWISE_SHAPES)
 @pytest.mark.parametrize(