[numpy] Change d2l chapters cv and gan to use numpy (#15368)

* Change op name style to lower case underscore

* Add ops under image to npx

* Add image submodule to npx

* Fix split_and_load use np

* Fix fine tuning

* Fix bbox and anchor

* Fix odd

* Fix ssd and rcnn

* Remove restriction on binary element-wise scalar

* Fix gan

* Fix sanity

* Try to fix website build failure

* Add npx.random.seed

* Fix doc

python/mxnet/_numpy_op_doc.py

@@ -21,7 +21,10 @@
 
 
 def _np_reshape(a, newshape, order='C'):
-    """Gives a new shape to an array without changing its data.
+    """
+    reshape(a, newshape, order='C')
+
+    Gives a new shape to an array without changing its data.
 
     Parameters
     ----------

python/mxnet/base.py

@@ -744,6 +744,7 @@ def write_all_str(module_file, module_all_list):
 _NP_OP_SUBMODULE_LIST = ['_random_', '_linalg_']
 
 _NP_EXT_OP_PREFIX = '_npx_'
+_NP_EXT_OP_SUBMODULE_LIST = ['_image_']
 
 _NP_INTERNAL_OP_PREFIX = '_npi_'
 
@@ -784,7 +785,7 @@ def _init_np_op_module(root_module_name, np_module_name, mx_module_name, make_op
         submodule_name_list = _NP_OP_SUBMODULE_LIST
     elif np_module_name == 'numpy_extension':
         op_name_prefix = _NP_EXT_OP_PREFIX
-        submodule_name_list = []
+        submodule_name_list = _NP_EXT_OP_SUBMODULE_LIST
     elif np_module_name == 'numpy._internal':
         op_name_prefix = _NP_INTERNAL_OP_PREFIX
         submodule_name_list = []

python/mxnet/gluon/block.py

@@ -26,7 +26,6 @@
 import re
 from collections import OrderedDict
 
-
 from ..base import mx_real_t, MXNetError
 from .. import symbol, ndarray, initializer
 from ..symbol import Symbol
@@ -37,7 +36,7 @@
 from .utils import _check_same_symbol_type, _check_all_np_ndarrays
 from .. import numpy_extension as _mx_npx
 from .. import numpy as _mx_np, numpy_extension as _mx_npx
-from .. util import is_np_array
+from .. util import is_np_array, np_shape, np_array
 
 
 class _BlockScope(object):
@@ -387,7 +386,25 @@ def load_parameters(self, filename, ctx=None, allow_missing=False,
         <https://mxnet.incubator.apache.org/tutorials/gluon/save_load_params.html>`_
         """
         if is_np_array():
-            loaded = _mx_npx.load(filename)
+            # failure may happen when loading parameters saved as NDArrays within
+            # NumPy semantics. Check the failure type and recover from it if it happens.
+            try:
+                loaded = _mx_npx.load(filename)
+            except MXNetError as e:
+                err_msg = str(e)
+                if 'is_np_shape' in err_msg:
+                    # Loading failure due to parameters saved without numpy semantics.
+                    # Temporarily disable numpy semantics and load parameters. After it's
+                    # done, resume the numpy semantics. This is fine because the cases
+                    # numpy ndarray covers is a superset of the legacy ndarray's.
+                    with np_array(False):
+                        with np_shape(False):
+                            loaded_nds = ndarray.load(filename)
+                    assert isinstance(loaded_nds, dict),\
+                        'expecting a dict type, got {}'.format(str(type(loaded_nds)))
+                    loaded = {k: loaded_nds[k].as_np_ndarray() for k in loaded_nds}
+                else:
+                    raise ValueError(err_msg)
         else:
             loaded = ndarray.load(filename)
         params = self._collect_params_with_prefix()

python/mxnet/gluon/data/vision/datasets.py

@@ -188,8 +188,9 @@ def _get_data(self):
         data = np.concatenate(data)
         label = np.concatenate(label)
 
-        self._data = nd.array(data, dtype=data.dtype)
-        self._label = label
+        array_fn = _mx_np.array if is_np_array() else nd.array
+        self._data = array_fn(data, dtype=data.dtype)
+        self._label = array_fn(label, dtype=label.dtype) if is_np_array() else label
 
 
 class CIFAR100(CIFAR10):

python/mxnet/gluon/data/vision/transforms.py

@@ -23,7 +23,7 @@
 from ...nn import Sequential, HybridSequential
 from .... import image
 from ....base import numeric_types
-from ...utils import _adapt_np_array
+from ....util import is_np_array
 
 
 class Compose(Sequential):
@@ -93,6 +93,8 @@ def __init__(self, dtype='float32'):
         self._dtype = dtype
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.cast(x, self._dtype)
 
 
@@ -134,8 +136,9 @@ class ToTensor(HybridBlock):
     def __init__(self):
         super(ToTensor, self).__init__()
 
-    @_adapt_np_array
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.to_tensor(x)
 
 
@@ -189,6 +192,8 @@ def __init__(self, mean=0.0, std=1.0):
         self._std = std
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.normalize(x, self._mean, self._std)
 
 
@@ -370,8 +375,9 @@ def __init__(self, size, keep_ratio=False, interpolation=1):
         self._size = size
         self._interpolation = interpolation
 
-    @_adapt_np_array
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.resize(x, self._size, self._keep, self._interpolation)
 
 class RandomFlipLeftRight(HybridBlock):
@@ -388,6 +394,8 @@ def __init__(self):
         super(RandomFlipLeftRight, self).__init__()
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_flip_left_right(x)
 
 
@@ -405,6 +413,8 @@ def __init__(self):
         super(RandomFlipTopBottom, self).__init__()
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_flip_top_bottom(x)
 
 
@@ -430,6 +440,8 @@ def __init__(self, brightness):
         self._args = (max(0, 1-brightness), 1+brightness)
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_brightness(x, *self._args)
 
 
@@ -455,6 +467,8 @@ def __init__(self, contrast):
         self._args = (max(0, 1-contrast), 1+contrast)
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_contrast(x, *self._args)
 
 
@@ -480,6 +494,8 @@ def __init__(self, saturation):
         self._args = (max(0, 1-saturation), 1+saturation)
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_saturation(x, *self._args)
 
 
@@ -505,6 +521,8 @@ def __init__(self, hue):
         self._args = (max(0, 1-hue), 1+hue)
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_hue(x, *self._args)
 
 
@@ -539,6 +557,8 @@ def __init__(self, brightness=0, contrast=0, saturation=0, hue=0):
         self._args = (brightness, contrast, saturation, hue)
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_color_jitter(x, *self._args)
 
 
@@ -562,4 +582,6 @@ def __init__(self, alpha):
         self._alpha = alpha
 
     def hybrid_forward(self, F, x):
+        if is_np_array():
+            F = F.npx
         return F.image.random_lighting(x, self._alpha)

python/mxnet/gluon/loss.py

@@ -258,30 +258,47 @@ def __init__(self, from_sigmoid=False, weight=None, batch_axis=0, **kwargs):
             weight, batch_axis, **kwargs)
         self._from_sigmoid = from_sigmoid
 
-    @_adapt_np_array
     def hybrid_forward(self, F, pred, label, sample_weight=None, pos_weight=None):
         label = _reshape_like(F, label, pred)
+        if is_np_array():
+            relu_fn = F.npx.relu
+            act_fn = F.npx.activation
+            abs_fn = F.np.abs
+            mul_fn = F.np.multiply
+            log_fn = F.np.log
+        else:
+            relu_fn = F.relu
+            act_fn = F.Activation
+            abs_fn = F.abs
+            mul_fn = F.broadcast_mul
+            log_fn = F.log
         if not self._from_sigmoid:
             if pos_weight is None:
                 # We use the stable formula: max(x, 0) - x * z + log(1 + exp(-abs(x)))
-                loss = F.relu(pred) - pred * label + \
-                    F.Activation(-F.abs(pred), act_type='softrelu')
+                loss = relu_fn(pred) - pred * label + \
+                    act_fn(-abs_fn(pred), act_type='softrelu')
             else:
                 # We use the stable formula: x - x * z + (1 + z * pos_weight - z) * \
                 #    (log(1 + exp(-abs(x))) + max(-x, 0))
-                log_weight = 1 + F.broadcast_mul(pos_weight - 1, label)
-                loss = pred - pred * label + log_weight * \
-                       (F.Activation(-F.abs(pred), act_type='softrelu') + F.relu(-pred))
+                log_weight = 1 + mul_fn(pos_weight - 1, label)
+                loss = pred - pred * label + log_weight *\
+                       (act_fn(-abs_fn(pred), act_type='softrelu') + relu_fn(-pred))
         else:
             eps = 1e-12
             if pos_weight is None:
-                loss = -(F.log(pred + eps) * label
-                         + F.log(1. - pred + eps) * (1. - label))
+                loss = -(log_fn(pred + eps) * label
+                         + log_fn(1. - pred + eps) * (1. - label))
             else:
-                loss = -(F.broadcast_mul(F.log(pred + eps) * label, pos_weight)
-                         + F.log(1. - pred + eps) * (1. - label))
+                loss = -(mul_fn(log_fn(pred + eps) * label, pos_weight)
+                         + log_fn(1. - pred + eps) * (1. - label))
         loss = _apply_weighting(F, loss, self._weight, sample_weight)
-        return F.mean(loss, axis=self._batch_axis, exclude=True)
+        if is_np_array():
+            if F is ndarray:
+                return F.np.mean(loss, axis=tuple(range(1, loss.ndim)))
+            else:
+                return F.npx.batch_flatten(loss).mean(axis=1)
+        else:
+            return F.mean(loss, axis=self._batch_axis, exclude=True)
 
 
 SigmoidBCELoss = SigmoidBinaryCrossEntropyLoss

python/mxnet/gluon/model_zoo/vision/resnet.py

@@ -33,6 +33,7 @@
 from ...block import HybridBlock
 from ... import nn
 from .... import base
+from .... util import is_np_array
 
 # Helpers
 def _conv3x3(channels, stride, in_channels):
@@ -81,7 +82,8 @@ def hybrid_forward(self, F, x):
         if self.downsample:
             residual = self.downsample(residual)
 
-        x = F.Activation(residual+x, act_type='relu')
+        act = F.npx.activation if is_np_array() else F.Activation
+        x = act(residual+x, act_type='relu')
 
         return x
 
@@ -129,7 +131,8 @@ def hybrid_forward(self, F, x):
         if self.downsample:
             residual = self.downsample(residual)
 
-        x = F.Activation(x + residual, act_type='relu')
+        act = F.npx.activation if is_np_array() else F.Activation
+        x = act(x + residual, act_type='relu')
         return x
 
 
@@ -165,13 +168,14 @@ def __init__(self, channels, stride, downsample=False, in_channels=0, **kwargs):
     def hybrid_forward(self, F, x):
         residual = x
         x = self.bn1(x)
-        x = F.Activation(x, act_type='relu')
+        act = F.npx.activation if is_np_array() else F.Activation
+        x = act(x, act_type='relu')
         if self.downsample:
             residual = self.downsample(x)
         x = self.conv1(x)
 
         x = self.bn2(x)
-        x = F.Activation(x, act_type='relu')
+        x = act(x, act_type='relu')
         x = self.conv2(x)
 
         return x + residual
@@ -211,17 +215,18 @@ def __init__(self, channels, stride, downsample=False, in_channels=0, **kwargs):
     def hybrid_forward(self, F, x):
         residual = x
         x = self.bn1(x)
-        x = F.Activation(x, act_type='relu')
+        act = F.npx.activation if is_np_array() else F.Activation
+        x = act(x, act_type='relu')
         if self.downsample:
             residual = self.downsample(x)
         x = self.conv1(x)
 
         x = self.bn2(x)
-        x = F.Activation(x, act_type='relu')
+        x = act(x, act_type='relu')
         x = self.conv2(x)
 
         x = self.bn3(x)
-        x = F.Activation(x, act_type='relu')
+        x = act(x, act_type='relu')
         x = self.conv3(x)
 
         return x + residual

python/mxnet/gluon/nn/activations.py

@@ -49,9 +49,8 @@ def _alias(self):
         return self._act_type
 
     def hybrid_forward(self, F, x):
-        if is_np_array():
-            F = F.npx
-        return F.Activation(x, act_type=self._act_type, name='fwd')
+        act = F.npx.activation if is_np_array() else F.Activation
+        return act(x, act_type=self._act_type, name='fwd')
 
     def __repr__(self):
         s = '{name}({_act_type})'
@@ -91,7 +90,8 @@ def __init__(self, alpha, **kwargs):
         self._alpha = alpha
 
     def hybrid_forward(self, F, x):
-        return F.LeakyReLU(x, act_type='leaky', slope=self._alpha, name='fwd')
+        leaky_relu = F.npx.leaky_relu if is_np_array() else F.LeakyReLU
+        return leaky_relu(x, act_type='leaky', slope=self._alpha, name='fwd')
 
     def __repr__(self):
         s = '{name}({alpha})'