Support visualization by op names

[anirudh2290]

mxnet visualization should support visualization by op names instead of node names.
For example,

mx.viz.plot_network(sym, use_op_names=True)

should use op names instead of node names for visualization.

[mxnet-label-bot]

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[kshitij12345]

I was planning to try this one. But I am a bit confused looking at the example output.

Running this,

import mxnet as mx
net = mx.sym.Variable('data')
net = mx.sym.FullyConnected(data=net, name='fc1', num_hidden=128)
net = mx.sym.Activation(data=net, name='relu1', act_type="relu")
net = mx.sym.FullyConnected(data=net, name='fc2', num_hidden=10)
net = mx.sym.SoftmaxOutput(data=net, name='out')
digraph = mx.viz.plot_network(net, shape={'data':(100,200)}, node_attrs={"fixedsize":"false"})
digraph.view()

Copied from https://mxnet.incubator.apache.org/api/python/tools/visualization.html#mxnet.visualization.plot_network

The output I get is,

which I believe is the expected behaviour.

---

https://github.com/apache/incubator-mxnet/blob/3d6646a4984839a5f37f8fa4f2a66880a303f1a5/python/mxnet/visualization.py#L339-L375

These lines format the label for node as per the Operator Name and its respective information.

Am I understanding anything incorrectly about the expected behaviour?
Thank You.

[anirudh2290]

@kshitij12345 thanks for taking a look at this! I think this is because the ops you see here FullyConnected, Activation are special cased here. If you use some other ops you may not see the operator name.