Intro to Recursive Neural Network in Deep Learning


Deep neural networks called recursive neural networks (RvNNs) are employed in natural language processing. When the same weights are used again to a structured input to produce a structured prediction, we get a recursive neural network. Business executives and IT specialists must comprehend what a recursive neural network is, what it can achieve, and how it functions.

Recursive Neural Network

A branch of machine learning and artificial intelligence (AI) known as "deep learning" aims to replicate how the human brain analyses information and learns certain concepts. Deep Learning's foundation is made up of neural networks. These are intended to precisely identify underlying patterns in a data collection and are roughly modelled after the human brain. Deep Learning provides the answer to the problem of predicting the unpredictable.

A subset of deep neural networks called recursive neural networks (RvNNs) are capable of learning organized and detailed data. By repeatedly using the same set of weights on structured inputs, RvNN enables you to obtain a structured prediction. Recursive refers to the neural network's application to its output.

Recursive neural networks are capable of handling hierarchical data because of their indepth tree-like structure. In a tree structure, parent nodes are created by joining child nodes. There is a weight matrix for every child-parent bond, and comparable children have the same weights. To allow for recursive operations and the use of the same weights, the number of children for each node in the tree is fixed. When it's necessary to parse a whole sentence, RvNNs are employed.

We add the weight matrices' (W i) and children's (C i) products and use the transformation f to determine the parent node's representation.

\[h = f \left( \sum_{i=1}^{i=c} W_i C_i \right) \], refers to the number of children.

Recurrent Neural Network vs. Recursive Neural Networks

  • Another well-known family of neural networks for processing sequential data is recurrent neural networks (RNNs). They are connected to the recursive neural network in a close way.

  • Given that language-related data like sentences and paragraphs are sequential in nature, recurrent neural networks are useful for representing temporal sequences in natural language processing (NLP). Chain topologies are frequently used in recurrent networks. By distributing the weights along the entire chain length, the dimensionality is maintained.

  • Recursive neural networks, on the other hand, work with hierarchical data models because of their tree structure. The tree may perform recursive operations and utilize the same weights at each step because each node has a set number of offspring. Parent representations are created by combining child representations.

  • A feed-forward network is less efficient than a recursive network.

  • Recursive networks are just a generalization of recurrent networks because recurrent networks are recurrent over time.

Recursive Neural Network Implementation

Sentiment analysis in natural language sentences is performed using a recursive neural network. Identifying the writing tone and thoughts of the author in a particular sentence is one of the most crucial jobs of natural language processing (NLP). Basic characterizations of the writing tone are understood whenever a writer displays any sentiment. To organize them in a syntactic hierarchy, we must first recognize the smaller parts, such as nouns or verb phrases. For instance, it indicates whether the sentence has a positive writing style or unfavorable word choices.

To create the ideal syntactic tree for a particular sentence, we must combine a specific pair of phrases and words, which is indicated by a variable called "score," which is generated at each traversal of nodes.

RvNNs for Natural Language Processing: Benefits

The structure and decrease in network depth of recursive neural networks are their two main advantages for natural language processing.

Recursive Neural Networks' tree structure, as previously mentioned, can manage hierarchical data, such as in parsing issues.

The ability for trees to have a logarithmic height is another advantage of RvNN. A recursive neural network could indeed represent a binary tree with a height of O(log n) when there are O(n) input words. The length between the first and the last input elements is shortened as a result. As a result, the long-term dependence becomes more manageable and shorter.

RvNNs for Natural Language Processing: Demerits

The tree structure of recursive neural networks may be their biggest drawback. Using the tree structure suggests giving our model a special inductive bias. The bias is consistent with the notion that the data are organized in a tree hierarchy. But the reality is different. As a result, the network might not be able to pick up on the current patterns.

The Recursive Neural Network also has a drawback in that sentence parsing can be cumbersome and slow. It's interesting that different parse trees can exist for the same text.

Additionally, labeling the training data for recursive neural networks takes more time and effort than building recurrent neural networks. It takes more time and effort to manually break down a sentence into smaller parts than it does to give it a label.


The fundamentals of deep learning and recursive neural networks have been discussed in this article. Understanding machine learning algorithms and their different types might help one get a clear understanding of the field's future possibilities.

One can better comprehend computer processing on datasets and extract more pertinent and worthwhile information from datasets by understanding machine language algorithms.

Updated on: 28-Mar-2023

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