What's the correct reasoning behind solving the vanishing/exploding gradient problem in deep neural...
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I have read several blog posts where the solution to solve the vanishing/exploding gradient problem in a deep neural network is suggested to be using Relu activation function instead of tanH & sigmoid.
But, I have encountered an explanation by Prof. Andrew NG lecture that explains that a partial solution to the vanishing gradient problem is a better or more careful choice of the random initialization of weights in your neural network.
i.e the solution is:
To set the variance of Wi to be equal to 1/n, where n is the number of input features that are going into a neuron. Along with the assumption that the input features of activations are roughly mean 0 and standard variance 1. So, what it's doing is that it's trying to set each of the weight matrices w so that it's not too much bigger than 1 and not too much less than 1, therefore, it doesn't explode or vanish too quickly.
- So, if you are using a ReLu activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better**. - and if you are using a TanH activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better. - or in some cases, it's being suggested to use Xavier initialization
- Also, if we need we can tune of
variance parameteras another hyperparameter by multiplying into the above formula and tune that multiplier as part of your hyperparameter search.
Therefore, choosing a reasonable scaling for how to initialize the weights helps weights not to explode too quickly and not decay to zero too quickly, which in turn could help in training a reasonably deep network without the weights or the gradients exploding or vanishing too much and not simply using ReLu!.
Please correct me if my understanding is wrong or incomplete!
deep-learning activation-function
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$begingroup$
I have read several blog posts where the solution to solve the vanishing/exploding gradient problem in a deep neural network is suggested to be using Relu activation function instead of tanH & sigmoid.
But, I have encountered an explanation by Prof. Andrew NG lecture that explains that a partial solution to the vanishing gradient problem is a better or more careful choice of the random initialization of weights in your neural network.
i.e the solution is:
To set the variance of Wi to be equal to 1/n, where n is the number of input features that are going into a neuron. Along with the assumption that the input features of activations are roughly mean 0 and standard variance 1. So, what it's doing is that it's trying to set each of the weight matrices w so that it's not too much bigger than 1 and not too much less than 1, therefore, it doesn't explode or vanish too quickly.
- So, if you are using a ReLu activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better**. - and if you are using a TanH activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better. - or in some cases, it's being suggested to use Xavier initialization
- Also, if we need we can tune of
variance parameteras another hyperparameter by multiplying into the above formula and tune that multiplier as part of your hyperparameter search.
Therefore, choosing a reasonable scaling for how to initialize the weights helps weights not to explode too quickly and not decay to zero too quickly, which in turn could help in training a reasonably deep network without the weights or the gradients exploding or vanishing too much and not simply using ReLu!.
Please correct me if my understanding is wrong or incomplete!
deep-learning activation-function
$endgroup$
add a comment |
$begingroup$
I have read several blog posts where the solution to solve the vanishing/exploding gradient problem in a deep neural network is suggested to be using Relu activation function instead of tanH & sigmoid.
But, I have encountered an explanation by Prof. Andrew NG lecture that explains that a partial solution to the vanishing gradient problem is a better or more careful choice of the random initialization of weights in your neural network.
i.e the solution is:
To set the variance of Wi to be equal to 1/n, where n is the number of input features that are going into a neuron. Along with the assumption that the input features of activations are roughly mean 0 and standard variance 1. So, what it's doing is that it's trying to set each of the weight matrices w so that it's not too much bigger than 1 and not too much less than 1, therefore, it doesn't explode or vanish too quickly.
- So, if you are using a ReLu activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better**. - and if you are using a TanH activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better. - or in some cases, it's being suggested to use Xavier initialization
- Also, if we need we can tune of
variance parameteras another hyperparameter by multiplying into the above formula and tune that multiplier as part of your hyperparameter search.
Therefore, choosing a reasonable scaling for how to initialize the weights helps weights not to explode too quickly and not decay to zero too quickly, which in turn could help in training a reasonably deep network without the weights or the gradients exploding or vanishing too much and not simply using ReLu!.
Please correct me if my understanding is wrong or incomplete!
deep-learning activation-function
$endgroup$
I have read several blog posts where the solution to solve the vanishing/exploding gradient problem in a deep neural network is suggested to be using Relu activation function instead of tanH & sigmoid.
But, I have encountered an explanation by Prof. Andrew NG lecture that explains that a partial solution to the vanishing gradient problem is a better or more careful choice of the random initialization of weights in your neural network.
i.e the solution is:
To set the variance of Wi to be equal to 1/n, where n is the number of input features that are going into a neuron. Along with the assumption that the input features of activations are roughly mean 0 and standard variance 1. So, what it's doing is that it's trying to set each of the weight matrices w so that it's not too much bigger than 1 and not too much less than 1, therefore, it doesn't explode or vanish too quickly.
- So, if you are using a ReLu activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better**. - and if you are using a TanH activation function then setting the variance of Wi to be equal to
sqrt(2/n)works better. - or in some cases, it's being suggested to use Xavier initialization
- Also, if we need we can tune of
variance parameteras another hyperparameter by multiplying into the above formula and tune that multiplier as part of your hyperparameter search.
Therefore, choosing a reasonable scaling for how to initialize the weights helps weights not to explode too quickly and not decay to zero too quickly, which in turn could help in training a reasonably deep network without the weights or the gradients exploding or vanishing too much and not simply using ReLu!.
Please correct me if my understanding is wrong or incomplete!
deep-learning activation-function
deep-learning activation-function
asked 2 hours ago
anuanu
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