## What is the difference between backpropagation and Backpropagation Through Time?

The Backpropagation algorithm is suitable for the feed forward neural network on fixed sized input-output pairs. The Backpropagation Through Time is the application of Backpropagation training algorithm which is applied to the sequence data like the time series.

**How do you truncate backpropagation?**

Truncated Backpropagation Through Time

- Present a sequence of k1 timesteps of input and output pairs to the network.
- Unroll the network then calculate and accumulate errors across k2 timesteps.
- Roll-up the network and update weights.
- Repeat.

**Who invented Backpropagation Through Time?**

533-536 (1986). [R7] Reddit/ML, 2019. J. Schmidhuber on Seppo Linnainmaa, inventor of backpropagation in 1970.

### Why back propagation in RNN is called Backpropagation Through Time?

It is quite easy to calculate the derivative of loss with respect to V as it only depends on the values at the current time step. This algorithm is called backpropagation through time or BPTT for short as we used values across all the timestamps to calculate the gradients.

**Does Lstms use backpropagation?**

LSTM (Long short term Memory ) is a type of RNN(Recurrent neural network), which is a famous deep learning algorithm that is well suited for making predictions and classification with a flavour of the time.

**What is RTRL algorithm?**

A Real-Time Recurrent Learning (RTRL) Algorithm is a Gradient Descent Algorithm that is an online learning algorithm for training RNNs. AKA: Real-Time Recurrent Learning. Context: It is an improved version of BPTT algorithm as it computes untruncated gradients.

#### What is the difference between LSTM and GRU?

The key difference between GRU and LSTM is that GRU’s bag has two gates that are reset and update while LSTM has three gates that are input, output, forget. GRU is less complex than LSTM because it has less number of gates. GRU exposes the complete memory and hidden layers but LSTM doesn’t.

**Why is backpropagation needed?**

Backpropagation (backward propagation) is an important mathematical tool for improving the accuracy of predictions in data mining and machine learning. Essentially, backpropagation is an algorithm used to calculate derivatives quickly.

**What is backpropagation with example?**

Backpropagation is one of the important concepts of a neural network. For a single training example, Backpropagation algorithm calculates the gradient of the error function. Backpropagation can be written as a function of the neural network.

## Which is better Lstm or GRU?

In terms of model training speed, GRU is 29.29% faster than LSTM for processing the same dataset; and in terms of performance, GRU performance will surpass LSTM in the scenario of long text and small dataset, and inferior to LSTM in other scenarios.

**How does backpropagation in LSTM work?**

And one more new thing from LSTM that at each step, not only hidden output is fed to the next step but another inside value called state also is pulled out and threw to the next step. …