openai / pixel-cnn

Code for the paper "PixelCNN++: A PixelCNN Implementation with Discretized Logistic Mixture Likelihood and Other Modifications"
https://arxiv.org/abs/1701.05517
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Understanding edge cases #34

Open ThomasDelteil opened 6 years ago

ThomasDelteil commented 6 years ago

Just wanted to make sure my understanding is right. Looking at the formulas, on the edge case, maximizing the probability for x=-1 is maximizing this function: logProb(μ, σ) = (-1 - μ)/σ - log(1 + e^((-1 - μ)/σ)) Which means for optimality μ->-infinity And this work because at inference time the predicted values are clipped between the effective pixel range? How big is the impact on the neighboring edge values for which the optimal μ is -0.997 etc ?