feat(frontend API): add as_complex and its test (ivy-llc#26020)

ivy/functional/frontends/paddle/tensor/tensor.py

@@ -772,6 +772,20 @@ def inner(self, y, name=None):
     def mean(self, axis=None, keepdim=False, name=None):
         return paddle_frontend.mean(self, axis=axis, keepdim=keepdim)
 
+    @with_supported_dtypes({"2.5.1 and below": ("float32", "float64")}, "paddle")
+    def as_complex(self, name=None):
+        if self.ivy_array.shape[-1] != 2:
+            raise ivy.exceptions.IvyError(
+                "The size of the last dimension of tensor does not equals 2"
+            )
+        dtype = (
+            ivy.complex64 if ivy.dtype(self.ivy_array) == "float32" else ivy.complex128
+        )
+        re_part = self.ivy_array[..., 0]
+        im_part = ivy.multiply(1j, self.ivy_array[..., 1])
+        value = paddle_frontend.Tensor(ivy.add(re_part, im_part).astype(dtype))
+        return value
+
     @with_supported_dtypes(
         {"2.5.1 and below": ("float32", "float64", "int32", "int64")}, "paddle"
     )

ivy_tests/test_ivy/test_frontends/test_paddle/test_tensor/test_tensor.py

@@ -36,6 +36,26 @@ def _filter_query(query):
     )
 
 
+# as_complex
+@st.composite
+def _get_as_complex_inputs_(draw):
+    shape = draw(
+        helpers.get_shape(
+            min_num_dims=2, max_num_dims=5, min_dim_size=2, max_dim_size=10
+        )
+    )
+
+    x_dtype, x = draw(
+        helpers.dtype_and_values(
+            available_dtypes=helpers.get_dtypes("valid"),
+            shape=(*shape, 2),
+            min_value=0,
+            max_value=50,
+        )
+    )
+    return x_dtype, x
+
+
 # clip
 @st.composite
 def _get_clip_inputs(draw):
@@ -762,6 +782,37 @@ def test_paddle_tensor_argsort(
     )
 
 
+# as_complex
+@handle_frontend_method(
+    class_tree=CLASS_TREE,
+    init_tree="paddle.to_tensor",
+    method_name="as_complex",
+    dtypes_and_x=_get_as_complex_inputs_(),
+)
+def test_paddle_tensor_as_complex(
+    dtypes_and_x,
+    frontend_method_data,
+    init_flags,
+    method_flags,
+    frontend,
+    on_device,
+    backend_fw,
+):
+    input_dtype, x = dtypes_and_x
+    helpers.test_frontend_method(
+        init_input_dtypes=input_dtype,
+        backend_to_test=backend_fw,
+        init_all_as_kwargs_np={"data": x[0]},
+        method_input_dtypes=input_dtype,
+        method_all_as_kwargs_np={},
+        frontend_method_data=frontend_method_data,
+        init_flags=init_flags,
+        method_flags=method_flags,
+        frontend=frontend,
+        on_device=on_device,
+    )
+
+
 # as_real
 @handle_frontend_method(
     class_tree=CLASS_TREE,