add back triu in fluid (#27135) (#27188)

Author: yaoxuefeng6

python/paddle/fluid/layers/tensor.py

@@ -36,7 +36,7 @@
     'tensor_array_to_tensor', 'concat', 'sums', 'assign',
     'fill_constant_batch_size_like', 'fill_constant', 'argmin', 'argmax',
     'argsort', 'ones', 'zeros', 'reverse', 'has_inf', 'has_nan', 'isfinite',
-    'range', 'linspace', 'zeros_like', 'ones_like', 'diag', 'eye'
+    'range', 'linspace', 'zeros_like', 'ones_like', 'diag', 'eye', 'triu'
 ]
 
 
@@ -1725,3 +1725,9 @@ def ones_like(x, out=None):
         attrs={'value': 1.0},
         outputs={'Out': [out]})
     return out
+
+
+@deprecated(since="2.0.0", update_to="paddle.triu")
+def triu(input, diagonal=0, name=None):
+    import paddle
+    return paddle.tensor.triu(x=input, diagonal=diagonal, name=name)

python/paddle/fluid/tests/unittests/test_tril_triu_op.py

@@ -142,6 +142,18 @@ def test_api_with_dygraph(self):
             self.assertTrue(np.allclose(tril_out, np.tril(data)))
             self.assertTrue(np.allclose(triu_out, np.triu(data)))
 
+    def test_fluid_api(self):
+        data = np.random.random([1, 9, 9, 4]).astype('float32')
+        x = fluid.data(shape=[1, 9, -1, 4], dtype='float32', name='x')
+        triu_out = fluid.layers.triu(x)
+
+        place = fluid.CUDAPlace(0) if fluid.core.is_compiled_with_cuda(
+        ) else fluid.CPUPlace()
+        exe = fluid.Executor(place)
+        triu_out = exe.run(fluid.default_main_program(),
+                           feed={"x": data},
+                           fetch_list=[triu_out])
+
 
 if __name__ == '__main__':
     unittest.main()