faster and better convnet

This commit is contained in:
George Hotz 2020-10-25 13:48:44 -07:00
commit 8fcada8071
2 changed files with 19 additions and 14 deletions

View file

@ -22,17 +22,20 @@ class TinyBobNet:
# create a model with a conv layer
class TinyConvNet:
def __init__(self):
conv = 5
chans = 16
self.c1 = Tensor(layer_init_uniform(chans,1,conv,conv))
self.l1 = Tensor(layer_init_uniform(((28-conv+1)**2)*chans, 128))
self.l2 = Tensor(layer_init_uniform(128, 10))
# https://keras.io/examples/vision/mnist_convnet/
conv = 3
#inter_chan, out_chan = 32, 64
inter_chan, out_chan = 8, 16 # for speed
self.c1 = Tensor(layer_init_uniform(inter_chan,1,conv,conv))
self.c2 = Tensor(layer_init_uniform(out_chan,inter_chan,conv,conv))
self.l1 = Tensor(layer_init_uniform(out_chan*5*5, 10))
def forward(self, x):
x.data = x.data.reshape((-1, 1, 28, 28)) # hacks
x = x.conv2d(self.c1).relu()
x = x.conv2d(self.c1).relu().maxpool2x2()
x = x.conv2d(self.c2).relu().maxpool2x2()
x = x.reshape(Tensor(np.array((x.shape[0], -1))))
return x.dot(self.l1).relu().dot(self.l2).logsoftmax()
return x.dot(self.l1).logsoftmax()
def train(model, optim, steps, BS=128):
losses, accuracies = [], []
@ -77,7 +80,7 @@ class TestMNIST(unittest.TestCase):
def test_conv(self):
np.random.seed(1337)
model = TinyConvNet()
optimizer = optim.Adam([model.c1, model.l1, model.l2], lr=0.001)
optimizer = optim.Adam([model.c1, model.c2, model.l1], lr=0.001)
train(model, optimizer, steps=400)
evaluate(model)

View file

@ -174,23 +174,25 @@ register('conv2d', FastConv2D)
class MaxPool2x2(Function):
@staticmethod
def forward(ctx, x):
my, mx = (x.shape[2]//2)*2, (x.shape[3]//2)*2
stack = []
xup = x[:, :, :my, :mx]
for Y in range(2):
for X in range(2):
stack.append(x[:, :, Y::2, X::2][None])
stack.append(xup[:, :, Y::2, X::2][None])
stack = np.concatenate(stack, axis=0)
idxs = np.argmax(stack, axis=0)
ctx.save_for_backward(idxs)
ctx.save_for_backward(idxs, x.shape)
return np.max(stack, axis=0)
@staticmethod
def backward(ctx, grad_output):
idxs, = ctx.saved_tensors
s = grad_output.shape
ret = np.zeros((s[0], s[1], s[2]*2, s[3]*2), dtype=grad_output.dtype)
idxs,s = ctx.saved_tensors
my, mx = (s[2]//2)*2, (s[3]//2)*2
ret = np.zeros(s, dtype=grad_output.dtype)
for Y in range(2):
for X in range(2):
ret[:, :, Y::2, X::2] = grad_output * (idxs == (Y*2+X))
ret[:, :, Y:my:2, X:mx:2] = grad_output * (idxs == (Y*2+X))
return ret
register('maxpool2x2', MaxPool2x2)