What are vectors

An introduction to vectors

What are vectors?

Computers are unable to analyse unstructured data such as text, image, audio or geospatial data out of the box. To perform any sort of analysis, such as creating image based recommendation systems or text topic analysis, we need to convert them into a numerical format that a computer can understand. By using machine learning, we can convert the unstructured data into a numerical formats and feed it into specialised vector algorithms for a variety of use cases.

This conversion from unstructured data to numerical data is called vectorizing or encoding. Each item, that could be a single word, an image, or an audio file, is encoded into a list of numbers: this list is called a vector. The encoding process can be done by different kinds of algorithms, notably if it is done through a deep neural network, it is often called a deep learning vector embedding. Once encoded into a vector, the longer it is in length, the more information is represented about the data it encoded.

Relevance AI's Workflow

For example, the graphics above represents the word 'website' converted to a vector. We only visualise up to a length of 3 for the vector because humans can typically only visualize up to three dimensions (vector length of 3), but to properly encode a word that encapsulates as much of the word's meaning, we may need vector length or dimension in the hundreds or thousands. Although we cannot visualize it, this is an example of how a 6 dimensional-length vector of the word 'website' could look like:

website = [0.324, 0.241, 0.934, 0.424, 0.141, 0.242]

Once we have converted this data into vector form, computer algorithms can compare the numerical values among multiple vectors to determine the similarity among various data points. Similar to how your fingerprint or DNA is similar to people that are most similar to you: your parents or your siblings. The vector representation is the fingerprint of data, helping you find similarities within the different data points.

Vectors are much like fingerprints of data
Vectors are much like fingerprints of data

What is a vector space?

When we encode thousands of words using the same machine learning algorithm, we project these words into the same vector space. This allows us to place words with similar meanings closer to one another.

In the example below, we have encoded 3 words: 'dog', 'cat', and 'pizza'. The word 'dog' and 'cat' are used in the same context very often and are semantically more similar, as opposed to 'cat' and 'pizza'. This was learnt by the machine learning model and when we produce a vector from it, we can see below that the words 'cat' and 'dog' are closer to each other and far away from 'pizza'.

Vector Spaces


Vectors can capture semantic meaning and enable better similarity comparisons of data

By capturing all the different semantics and features of data into high dimensional vectors, we can use it to essentially perform better similarity analysis between data of any kind as long as it can be vectorized. By solving this similarity problem, we enable a wide array of use cases such as search, recommendations, predictions, etc.

In the example above, the vectors were produced from BERT, an NLP model from Google which produces a vector length of 768. For interpretation purposes, we have used a method of dimensionality reduction that compresses the vector length into 3 allowing the vector to be visualized.

Similar items are closer to each other
Similar items are closer to each other