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Unstable Gradient Problem. Nielsen claims that when training a deep feedforward neural network using Stochastic Gradient Descent (SGD) and backpropagation, the main difficulty in the training is the “unstable gradient problem”.

## Why it is hard to train deep neural networks?

More generally, it turns out that the gradient in deep neural networks is unstable, tending to either explode or vanish in earlier layers. This instability is a fundamental problem for gradient-based learning in deep neural networks.

## Do deeper neural networks take longer to train?

If you build a very wide, very deep network, you run the chance of each layer just memorizing what you want the output to be, and you end up with a neural network that fails to generalize to new data. Aside from the specter of overfitting, the wider your network, the longer it will take to train.

## How do I train very deep neural network?

How to train your Deep Neural Network

- Training data. …
- Choose appropriate activation functions. …
- Number of Hidden Units and Layers. …
- Weight Initialization. …
- Learning Rates. …
- Hyperparameter Tuning: Shun Grid Search – Embrace Random Search. …
- Learning Methods. …
- Keep dimensions of weights in the exponential power of 2.

## How long does it take to train deep neural networks?

It might take about 2-4 hours of coding and 1-2 hours of training if done in Python and Numpy (assuming sensible parameter initialization and a good set of hyperparameters). No GPU required, your old but gold CPU on a laptop will do the job. Longer training time is expected if the net is deeper than 2 hidden layers.

## Are deeper neural networks better?

For the same level of accuracy, deeper networks can be much more efficient in terms of computation and number of parameters. Deeper networks are able to create deep representations, at every layer, the network learns a new, more abstract representation of the input. A shallow network has less number of hidden layers.

## What are the main challenges of neural networks?

Disadvantages of Neural Networks

- Black Box. The very most disadvantage of a neural network is its black box nature. …
- The Duration of Network Development. There are lots of libraries like Keras that make the development of neural networks fairly simple. …
- Amount of Data.

## How long does it take to train a ML model?

On average, 40% of companies said it takes more than a month to deploy an ML model into production, 28% do so in eight to 30 days, while only 14% could do so in seven days or less.

## Do deep Nets need deep?

Currently, deep neural networks are the state of the art on problems such as speech recognition and computer vision. In this paper we empirically demonstrate that shallow feed-forward nets can learn the complex functions previously learned by deep nets and achieve accuracies previously only achievable with deep models.

## When and why are deep networks better than shallow ones?

While the universal approximation property holds both for hierarchical and shallow networks, deep networks can approximate the class of compositional functions as well as shallow networks but with exponentially lower number of training parameters and sample complexity.

## How does deep learning differ from machine learning?

Machine learning uses algorithms to parse data, learn from that data, and make informed decisions based on what it has learned. Deep learning structures algorithms in layers to create an “artificial neural network” that can learn and make intelligent decisions on its own.

## How deep learning training is done?

Deep Learning uses a Neural Network to imitate animal intelligence. There are three types of layers of neurons in a neural network: the Input Layer, the Hidden Layer(s), and the Output Layer. Connections between neurons are associated with a weight, dictating the importance of the input value.

## What will happen if we initialize all the weights to 0 in neural networks?

Initializing all the weights with zeros leads the neurons to learn the same features during training. … Thus, both neurons will evolve symmetrically throughout training, effectively preventing different neurons from learning different things.

## Can I learn AI in 6 months?

While there are great starting points for a career in AI, ML, you need to invest your time in learning the skills required to build a career in these technologies. … Here are 4 online courses that will make you an expert in AI, ML within six months.

## Can we directly learn Deep Learning?

However it is unlikely you will be able to understand Deep Learning properly without understanding machine learning – the principles of generalization, regularization,cross-validation, (stochastic) gradient descent, simple linear models like linear regression / logistic regression, margin classifiers like SVM etc.

## Why is my neural network so bad?

Your Network contains Bad Gradients. You Initialized your Network Weights Incorrectly. You Used a Network that was too Deep. You Used the Wrong Number of Hidden Units.