Write padding aware im2col?

[mavenlin]

@Yangqing Is there any specific reason for an individual padding layer but not supporting padding in im2col? My concern is that the padding layer causes unnecessary extra memory usage which can be avoided. Is it necessary to implement padding aware im2col function?

[Yangqing]

Just legacy reason, I guess... I was translating codes quickly from decaf to caffe and did not worry too much about memory consumption back then. Yeah, it would be good to have a padding aware im2col function to save a (rather unnecessary) copy of the data.

[sguada]

It would be even better to have a more memory efficient convolutional layer
that won't require im2col, but that it is going to be harder.

Sergio

2014-02-03 Yangqing Jia notifications@github.com:

Just legacy reason, I guess... I was translating codes quickly from decaf
to caffe and did not worry too much about memory consumption back then.
Yeah, it would be good to have a padding aware im2col function to save a
(rather unnecessary) copy of the data.

Reply to this email directly or view it on GitHubhttps://github.com//issues/36#issuecomment-34001933
.

[Yangqing]

I assume Forrest is working along that direction (not sure).

Yangqing

On Mon, Feb 3, 2014 at 1:40 PM, Sergio Guadarrama
notifications@github.comwrote:

It would be even better to have a more memory efficient convolutional layer
that won't require im2col, but that it is going to be harder.

Sergio

2014-02-03 Yangqing Jia notifications@github.com:

Just legacy reason, I guess... I was translating codes quickly from decaf
to caffe and did not worry too much about memory consumption back then.
Yeah, it would be good to have a padding aware im2col function to save a
(rather unnecessary) copy of the data.

Reply to this email directly or view it on GitHub<
https://github.com/BVLC/caffe/issues/36#issuecomment-34001933>
.

Reply to this email directly or view it on GitHubhttps://github.com//issues/36#issuecomment-34003395
.

[sguada]

I was talking with Forrest, and he plans to work on that in a week or two.

I found this examples about convolutions
http://www.evl.uic.edu/sjames/cs525/final.html

[zimenglan-sysu]

@Yangqing how to convert the 2 dimension convolution to 3 dimension convolution in the im2col.cpp and conv_layer.cpp files? Thinks