personal repo for experimenting with neural networks
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Connor Olding a12121c16a rewrite readme and example code 2 months ago
onn comment on NLL implementation 3 months ago
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README.md rewrite readme and example code 2 months ago
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README.md

neural network stuff

not unlike my DSP repo, onn is a bunch of half-baked python code that’s kinda handy. i give no guarantee anything provided here is correct.

don’t expect commits, docs, or comments to be any verbose. however, i do attempt to cite and source any techniques used.

alternatives

when creating this, i wanted a library free of compilation and heavy dependencies — other than numpy and scipy, but these are commonplace. although onn is significantly faster than equivalent autograd code, performance is not a concern and it cannot run on GPU.

since this is my personal repo, i recommend that others do not rely on it. instead, consider one of the following:

  • keras it’s now integrated directly into tensorflow.. it runs on CPU and GPU. however, it requires a compilation stage.
  • also check out the keras-contrib library for more keras components based on recent papers.
  • the library itself may be discontinued, but theano’s source code contains pure numpy test methods as reference.
  • minpy for tensor-powered numpy routines and automatic differentiation. deprecated by mxnet. i’ve never used either so i don’t know what mxnet is like.
  • autograd for automatic differentiation without tensors. this is my personal favorite, although it is a little slow.
  • autograd has been discontinued in favor of Google’s JAX, however, JAX is quite heavy and non-portable in comparison. JAX runs on CPU and GPU and it can skip compilation on CPU.

dependencies

python 3.5+

mandatory packages: numpy scipy

needed for saving weights: h5py

used in example code: dotmap

minimal example

#!/usr/bin/env python3
import numpy as np
import mnists  # https://github.com/notwa/mnists
from onn import *

train_x, train_y, valid_x, valid_y = mnists.prepare("mnist")
learning_rate = 0.01
epochs = 20
batch_size = 500
hidden_size = 196  # 1/4 the number of pixels in an mnist sample
reg = L1L2(1e-5, 1e-4)
final_reg = None

x = Input(shape=train_x.shape[1:])  # give the shape of a single example
y = x  # superficial code just to make changing layer order a little easier
y = y.feed(Flatten())
y = y.feed(Dense(hidden_size, init=init_he_normal, reg_w=reg, reg_b=reg))
y = y.feed(Dropout(0.5))
y = y.feed(GeluApprox())
y = y.feed(Dense(10, init=init_glorot_uniform, reg_w=final_reg, reg_b=final_reg))
y = y.feed(Softmax())
model = Model(x, y,  # follow the graph from node x to y
              loss=CategoricalCrossentropy(), mloss=Accuracy(),
              unsafe=True)  # skip some sanity checks to go faster

optim = Adam()  # good ol' adam
learner = WaveCLR(optim, upper_rate=learning_rate,
                  epochs=epochs, period=epochs)  # ramp up and down the rate
ritual = Ritual(learner=learner)  # the accursed deep-learning ritual

ritual.prepare(model)  # reset training
while learner.next():
    print("epoch", learner.epoch)
    losses = ritual.train(*batchize(train_x, train_y, batch_size))
    print("train accuracy", "{:6.2%}".format(losses.avg_mloss))

def print_error(name, train_x, train_y):
    losses = ritual.test_batched(train_x, train_y, batch_size)
    print(name + " loss", "{:12.6e}".format(losses.avg_loss))
    print(name + " accuracy", "{:6.2%}".format(losses.avg_mloss))
print_error("train", train_x, train_y)
print_error("valid", valid_x, valid_y)
predicted = model.evaluate(train_x)  # use this as you will!

(mnists is available here)

contributing

i’m just throwing this code out there, so i don’t actually expect anyone to contribute, but if you do find a blatant issue, maybe yell at me on twitter.