[ Hackathon 3rd No.2 ] add paddle.iinfo (#45321)

paddle/fluid/eager/grad_node_info.h

@@ -302,7 +302,7 @@ class GradNodeBase {
   // Gradient Hooks
   // Customer may register a list of hooks which will be called in order during
   // backward
-  // Each entry consists one pair of
+  // Each entry consists of one pair of
   // <hook_id, <out_rank, std::shared_ptr<TensorHook>>>
   std::map<int64_t,
            std::tuple<

paddle/fluid/pybind/pybind.cc

@@ -21,6 +21,7 @@ limitations under the License. */
 #include <map>
 #include <memory>
 #include <mutex>  // NOLINT // for call_once
+#include <sstream>
 #include <string>
 #include <tuple>
 #include <type_traits>
@@ -346,6 +347,52 @@ bool IsCompiledWithDIST() {
 #endif
 }
 
+struct iinfo {
+  int64_t min, max;
+  int bits;
+  std::string dtype;
+
+  explicit iinfo(const framework::proto::VarType::Type &type) {
+    switch (type) {
+      case framework::proto::VarType::INT16:
+        min = std::numeric_limits<int16_t>::min();
+        max = std::numeric_limits<int16_t>::max();
+        bits = 16;
+        dtype = "int16";
+        break;
+      case framework::proto::VarType::INT32:
+        min = std::numeric_limits<int32_t>::min();
+        max = std::numeric_limits<int32_t>::max();
+        bits = 32;
+        dtype = "int32";
+        break;
+      case framework::proto::VarType::INT64:
+        min = std::numeric_limits<int64_t>::min();
+        max = std::numeric_limits<int64_t>::max();
+        bits = 64;
+        dtype = "int64";
+        break;
+      case framework::proto::VarType::INT8:
+        min = std::numeric_limits<int8_t>::min();
+        max = std::numeric_limits<int8_t>::max();
+        bits = 8;
+        dtype = "int8";
+        break;
+      case framework::proto::VarType::UINT8:
+        min = std::numeric_limits<uint8_t>::min();
+        max = std::numeric_limits<uint8_t>::max();
+        bits = 8;
+        dtype = "uint8";
+        break;
+      default:
+        PADDLE_THROW(platform::errors::InvalidArgument(
+            "the argument of paddle.iinfo can only be paddle.int8, "
+            "paddle.int16, paddle.int32, paddle.int64, or paddle.uint8"));
+        break;
+    }
+  }
+};
+
 static PyObject *GetPythonAttribute(PyObject *obj, const char *attr_name) {
   // NOTE(zjl): PyObject_GetAttrString would return nullptr when attr_name
   // is not inside obj, but it would also set the error flag of Python.
@@ -555,6 +602,21 @@ PYBIND11_MODULE(core_noavx, m) {
 
   BindException(&m);
 
+  py::class_<iinfo>(m, "iinfo")
+      .def(py::init<const framework::proto::VarType::Type &>())
+      .def_readonly("min", &iinfo::min)
+      .def_readonly("max", &iinfo::max)
+      .def_readonly("bits", &iinfo::bits)
+      .def_readonly("dtype", &iinfo::dtype)
+      .def("__repr__", [](const iinfo &a) {
+        std::ostringstream oss;
+        oss << "paddle.iinfo(min=" << a.min;
+        oss << ", max=" << a.max;
+        oss << ", bits=" << a.bits;
+        oss << ", dtype=" << a.dtype << ")";
+        return oss.str();
+      });
+
   m.def("set_num_threads", &platform::SetNumThreads);
 
   m.def("disable_signal_handler", &DisableSignalHandler);

python/paddle/__init__.py

@@ -38,6 +38,7 @@ from .framework import in_dynamic_mode  # noqa: F401
 from .fluid.dataset import *  # noqa: F401
 from .fluid.lazy_init import LazyGuard  # noqa: F401
 
+from .framework.dtype import iinfo  # noqa: F401
 from .framework.dtype import dtype as dtype  # noqa: F401
 from .framework.dtype import uint8  # noqa: F401
 from .framework.dtype import int8  # noqa: F401
@@ -386,6 +387,7 @@ if is_compiled_with_cinn():
 disable_static()
 
 __all__ = [  # noqa
+    'iinfo',
     'dtype',
     'uint8',
     'int8',

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

+# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import paddle
+import unittest
+import numpy as np
+
+
+class TestIInfoAndFInfoAPI(unittest.TestCase):
+
+    def test_invalid_input(self):
+        for dtype in [
+                paddle.float16, paddle.float32, paddle.float64, paddle.bfloat16,
+                paddle.complex64, paddle.complex128, paddle.bool
+        ]:
+            with self.assertRaises(ValueError):
+                _ = paddle.iinfo(dtype)
+
+    def test_iinfo(self):
+        for paddle_dtype, np_dtype in [(paddle.int64, np.int64),
+                                       (paddle.int32, np.int32),
+                                       (paddle.int16, np.int16),
+                                       (paddle.int8, np.int8),
+                                       (paddle.uint8, np.uint8)]:
+            xinfo = paddle.iinfo(paddle_dtype)
+            xninfo = np.iinfo(np_dtype)
+            self.assertEqual(xinfo.bits, xninfo.bits)
+            self.assertEqual(xinfo.max, xninfo.max)
+            self.assertEqual(xinfo.min, xninfo.min)
+            self.assertEqual(xinfo.dtype, xninfo.dtype)
+
+
+if __name__ == '__main__':
+    unittest.main()

python/paddle/framework/dtype.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from ..fluid.core import VarDesc
+from ..fluid.core import iinfo as core_iinfo
 
 dtype = VarDesc.VarType
 dtype.__qualname__ = "dtype"
@@ -34,4 +35,37 @@ complex128 = VarDesc.VarType.COMPLEX128
 
 bool = VarDesc.VarType.BOOL
 
-__all__ = []
+
+def iinfo(dtype):
+    """
+
+    paddle.iinfo is a function that returns an object that represents the numerical properties of 
+    an integer paddle.dtype.
+    This is similar to `numpy.iinfo <https://numpy.org/doc/stable/reference/generated/numpy.iinfo.html#numpy-iinfo>`_.
+
+    Args:
+        dtype(paddle.dtype):  One of paddle.uint8, paddle.int8, paddle.int16, paddle.int32, and paddle.int64.
+
+    Returns:
+        An iinfo object, which has the following 4 attributes:
+
+            - min: int, The smallest representable integer number.
+            - max: int, The largest representable integer number.
+            - bits: int, The number of bits occupied by the type.
+            - dtype: str, The string name of the argument dtype.
+
+    Examples:
+        .. code-block:: python
+
+            import paddle
+
+            iinfo_uint8 = paddle.iinfo(paddle.uint8)
+            print(iinfo_uint8)
+            # paddle.iinfo(min=0, max=255, bits=8, dtype=uint8)
+            print(iinfo_uint8.min) # 0
+            print(iinfo_uint8.max) # 255
+            print(iinfo_uint8.bits) # 8
+            print(iinfo_uint8.dtype) # uint8
+
+    """
+    return core_iinfo(dtype)