@jeremyphoward ‘s and http://fast.ai ‘s influence I’m sure ;)
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Replying to @graphific @jeremyphoward
actually besides http://fast.ai i always credit
@chollet's DL book, starting with its very early draft; so the choice of Xception and use of Keras is due to the latter :)1 reply 0 retweets 2 likes -
I haven't been recommending Xception because grouped convs and depthwise separable convs are still slow in CuDNN AFAIK.
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i like how lean is the Xception model, will try to compare the inference speed bw my previous VGG-like and Xception
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Vgg is the slowest. Compare to rn34
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ok - i abandoned resnets in favor of xception due to the former requiring larger size of input image; will revisit
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No modern CNN requires a specific input size. You can use any size you like with rn34. Be sure to use adaptive pooling to make this work (fastai does that for you)
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Replying to @jeremyphoward @graphific
Keras API puts a low boundary on the input image size - ex for rn50 it requires input size to be no smaller than 197
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Hi Helena, all modern CNNs operate downsampling on their inputs, which means they start with large feature maps that get smaller as you do down the network. In general, convolution is a downsampling operating unless you explicit pad your inputs.
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Replying to @fchollet @jeremyphoward
That's only partially true: for discriminative models yes, but there's no inherent reason why convolutions should equals downsampling (for generative models for instance).
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*Of course* you can design architectures that don't do downsampling (just don't include maxpooling or strides, and use "same" padding everywhere). And there are use cases for it. I'm just talking about every pre-trained architecture available out there.
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This is completely unviable if you try to do image classification on relatively large inputs, btw.
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Replying to @fchollet @jeremyphoward
Sure, for classification problems, but not necessarily for language or image modelling or generation where you'd actually prefer to keep image sizes relatively stable in the network, or even enlarge them (eg super resolution).
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