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A New Approach to Tensor Compression

Discover a flexible method for effective tensor compression across various applications.

― 6 min read


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Tensors are like multi-dimensional boxes filled with numbers. They are used to store complex information in many fields, like science, finance, and technology. However, saving these tensors without shrinking their size can take up a lot of space, especially when the data is very large. When we try to store them as they are, it can become increasingly difficult and costly, especially for devices with limited memory.

To address this issue, people have developed various methods to reduce the size of tensors. These methods help to compress the data, making it easier to store and transfer. Unfortunately, many of these techniques have strict rules about the kind of data they can work with. They often assume that the data has certain properties, such as being sparse (having a lot of zeros) or having a low rank (not needing many dimensions to represent it).

In this article, we will introduce a new method for compressing tensors without relying on these strict rules. Our approach is flexible and can handle different kinds of tensors, which makes it suitable for various applications.

What are Tensors?

Tensors are essentially higher-dimensional arrays. If you think of a simple number grid, that's a two-dimensional matrix. A tensor can have three dimensions (like a cube of numbers) or even more. They are useful for representing complex datasets, such as video frames or multi-sensor readings in smart devices.

Real-world examples of tensors include:

  • Sensor data from weather stations
  • Financial data tracking stock prices
  • The features extracted from videos

However, these datasets can get very large. For example, storing a tensor related to music data can consume significant storage space.

The Need for Compression

Storing large tensors without any compression can lead to several problems:

  1. Memory Limitations: Devices like smartphones or IoT devices may not have enough memory to store large amounts of data.
  2. High Costs: Transmitting large datasets can be expensive, especially if you're using cloud services or data plans.
  3. Efficiency: Working with smaller datasets speeds up processing times.

Given these challenges, tensor compression becomes essential.

Existing Compression Methods

There are many tensor compression methods available, but most of them have specific conditions they need to follow. For instance:

  • Some methods work well only for 2D or 3D data.
  • Others require the data to have many zeros or to be arranged in a specific way.

These limitations mean that for many real-world datasets, existing methods may not provide adequate results.

Our Approach

We propose a new compression method that is more flexible and effective at handling various kinds of tensors without strict rules. Here are the key components of our approach:

Neural Tensor-Train Decomposition

Our method starts with an advanced technique called Neural Tensor-Train Decomposition. This technique combines traditional tensor decomposition with a recurrent neural network (RNN). The RNN allows for more complex interactions between data points, enabling the model to learn patterns in the data without being limited by the strict rules of traditional methods.

Folding Input Tensors

To further enhance compression, we fold the input tensor into a higher-dimensional tensor. This folding process reduces the number of elements needed to represent the tensor while maintaining the same amount of information. The idea is similar to how a sheet of paper can be folded to take up less space.

Reordering Mode Indices

Our third component involves reordering the way we look at different dimensions of the tensor. By organizing the data more effectively, we can make better use of the relationships between different entries within the tensor. This step is crucial for improving the overall Accuracy of our compression method.

Advantages of Our Method

Through rigorous testing with real-world datasets, we have identified several advantages of our approach:

  1. Concise Compression: Our method can produce smaller file sizes compared to other well-known methods, and it does this without sacrificing the quality of the reconstructed data.
  2. High Accuracy: When we have the same target size for compressed data, our method offers more accurate reconstructions than competitors.
  3. Scalability: Our model's time for compression grows linearly with the number of entries in the tensor, making it efficient even for large datasets.

Detailed Analysis of Our Method

Compression Performance

We tested our method using various real-world datasets to measure its performance. The results show that our compression method outperforms traditional ones in several critical areas:

  • For datasets like stock price tracking, our method achieved a compression size that was 7.38 times smaller than the second-best method while maintaining similar accuracy.
  • In terms of accuracy alone, when the total sizes of Compressions were close, our method provided a reconstruction accuracy that was 3.33 times better than the best competitor.

Effectiveness of Each Component

To see how well each part of our method works, we performed tests by removing components of the method. Each time we did this, the accuracy of the compression decreased, showing that every part of our approach contributes positively to the overall effectiveness.

Scalability

One of the significant benefits of our compression method is its ability to scale efficiently. As we increased the size of the input tensor, the time it took to compress the data increased almost linearly. This means that even as the datasets grow larger, our compression method remains practical.

Moreover, the time taken to reconstruct data from the compressed output grows logarithmically with respect to the largest dimension of the tensor. This makes our method quick and efficient, even when dealing with large tensors.

Compression Time Comparison

When we compared the total time taken by our compression method with other methods, we found that while our method needs more time than straightforward algorithms, it is significantly faster than deep learning-based methods like NeuKron, which can take over 24 hours to compress large datasets.

Conclusion

In conclusion, we have introduced an innovative method for tensor compression that does not rely on strict assumptions about the data. Our approach combines advanced techniques like Neural Tensor-Train Decomposition, folding processes, and intelligent reordering of data.

By using this method, we can achieve a balance between size reduction and accuracy, making it suitable for various applications across different fields. As the need for efficient data storage and transmission continues to grow, our compression method provides a promising solution to these challenges, paving the way for better data handling in a modern data-driven world.

Original Source

Title: TensorCodec: Compact Lossy Compression of Tensors without Strong Data Assumptions

Abstract: Many real-world datasets are represented as tensors, i.e., multi-dimensional arrays of numerical values. Storing them without compression often requires substantial space, which grows exponentially with the order. While many tensor compression algorithms are available, many of them rely on strong data assumptions regarding its order, sparsity, rank, and smoothness. In this work, we propose TENSORCODEC, a lossy compression algorithm for general tensors that do not necessarily adhere to strong input data assumptions. TENSORCODEC incorporates three key ideas. The first idea is Neural Tensor-Train Decomposition (NTTD) where we integrate a recurrent neural network into Tensor-Train Decomposition to enhance its expressive power and alleviate the limitations imposed by the low-rank assumption. Another idea is to fold the input tensor into a higher-order tensor to reduce the space required by NTTD. Finally, the mode indices of the input tensor are reordered to reveal patterns that can be exploited by NTTD for improved approximation. Our analysis and experiments on 8 real-world datasets demonstrate that TENSORCODEC is (a) Concise: it gives up to 7.38x more compact compression than the best competitor with similar reconstruction error, (b) Accurate: given the same budget for compressed size, it yields up to 3.33x more accurate reconstruction than the best competitor, (c) Scalable: its empirical compression time is linear in the number of tensor entries, and it reconstructs each entry in logarithmic time. Our code and datasets are available at https://github.com/kbrother/TensorCodec.

Authors: Taehyung Kwon, Jihoon Ko, Jinhong Jung, Kijung Shin

Last Update: 2023-09-20 00:00:00

Language: English

Source URL: https://arxiv.org/abs/2309.10310

Source PDF: https://arxiv.org/pdf/2309.10310

Licence: https://creativecommons.org/licenses/by/4.0/

Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.

Thank you to arxiv for use of its open access interoperability.

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