Lesson 3 In-Class Discussion


(Jeremy Howard (Admin)) #1

This thread contains the in-class discussion from Lesson 3. The Wiki links have been moved to this new thread. Please ask any questions about lesson 3 in the new wiki thread.


Any Ideas on how to modify Resnet with Images that have 2 channels?
Dog Breed Identification challenge
Dog Breed Identification challenge
(Jeremy Howard (Admin)) #2

(Shruti Mittal) #3

The live stream has not started yet right? Or is it just me


(Jeremy Howard (Admin)) #4

Not for an hour.


(Arjun Rajkumar) #5

Had a doubt regarding creating a submission file for Kaggle. The competition page says :

Submissions are evaluated on **Multi Class Log Loss** between the predicted probability and the observed target.

logloss=−1N∑i=1N∑j=1Myi,jlog(pi,j)

Just wondering when did we apply this formula in our model? And how could we change our code if they required some other log loss other than multi class?

Thanks!


(Divyansh Jha) #6

when will the stream start?


(Anand Saha) #7

The loss criteria gets chosen by virtue of the data in fastai as assigned to self.crit below:

fastai/conv_learner.py

class ConvLearner(Learner):
    def __init__(self, data, models, precompute=False, **kwargs):
        self.precompute = False
        super().__init__(data, models, **kwargs)
        self.crit = F.binary_cross_entropy if data.is_multi else F.nll_loss
        if data.is_reg: self.crit = F.l1_loss

binary_cross_entropy, nll_loss and l1_loss can be looked up here: http://pytorch.org/docs/master/nn.html


(Saurabh Jha) #8


Looks like live stream has not started, please let me know if there is another link to live stream


(Anand Saha) #9

It’s due in 15 mins. (6:30 PM PST, 8 AM IST)


#10

Not started yet.


(Pete Condon) #11

The live stream is still offline?


(Vikrant Behal) #12

Yes, It’s.


(Alex) #13

Its offline for me still


(Ankit Goila) #14

Correct url: https://www.youtube.com/watch?v=_VpaKaMyjqI


(Maureen Metzger) #15

Thanks, Ankit!


(asaia) #16

Thank you


(Ankit Goila) #17

It has been updated in the wiki above.


(Setu) #18

what is the environment file?


(Stathis Fotiadis) #19

@jeremy Could we get the rest of the links you presented in the beginning please?


(Nahid Alam) #20

@jeremy Can you please share all the blog links here in the wiki section that you just showed in the class?