What is the different options for pooler_type in Bert config ?
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## Details
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I want to change the pooling type at the top of the output hidden states of Bert.
I search in the documentation and find nothing. Can anyone help me ? I just want the different option of pooling (max, average etc.). Here's a piece of code to see the option i am talking about.
`import transformers
encoder = transformers.TFBertModel.from_pretrained("bert-base-uncased")
encoder.config`
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**A link to original question on Stack Overflow**:

Hi! The pooler is actually a linear layer, that is used on top of the BERT encoder (the hidden layers). It's not doing a pooling operation like average or max pooling.
<|||||>Ok i read that somewhere. But my is on what component ? If you use a pooler on the last layer of bert encoder you will get an output of size [batch, step, dense_unit], but i am sure that the pooler output is a squeeze_first output. Why is there a information about pooler_type in the config, if we cannot change the pooler_type ?