Submitted:
01 October 2025
Posted:
02 October 2025
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Abstract
Keywords:
Introduction
- Binding (element-wise multiplication, ⊗): links two concepts represented in the vectors together. For example, binding the vector representation of the concept serum level with the vector representation of the concept high creates a new, distinct hypervector representing the composite idea high serum level;
- Bundling (element-wise addition, ⊕): combines multiple concepts in vector format. One could bundle the vectors for high serum glucose, high blood pressure, and patient ID: 123 to create a single vector representing a patient’s state. This operation highlights a key property of HDC: the ability to easily integrate heterogeneous information, numerical values, categorical states, or identifiers, into one coherent data structure;
- Permutation (rotation, ρ): encodes order of sequences, which is critical for representing sequential data like DNA strands or time-series events in a patient’s record. In this operation, each hypervector is shifted or rotated according to its position in the sequence, ensuring that the same concept appearing at different positions is represented uniquely. This positional encoding preserves order while keeping the representations nearly orthogonal, thereby allowing clear distinction between sequences and their components.
Tip 1: For Electronic Health Records – Use Bundling to Create Holistic Patient Vectors
How to Create a Patient Vector
- Keys for data types: diagnosis, medication, lab_test, value;
- Specific diagnose: diabetes_type_2, hypertension;
- Specific medications: metformin, lisinopril;
- Specific lab tests: hba1c, creatinine;
- Discretized lab values: high, normal, low.


- A diagnosis of hypertension becomes: patient_diagnosis = diagnosis ⊗ hypertension
- A prescription for metformin becomes: patient_prescription = medication ⊗ metformin
- A HbA1c result of 8.1% (which we categorize as high) becomes: patient_hba1c = (lab_test ⊗ hba1c) ⊕ (value ⊗ high)


Why This Works
- Robustness to missing data: Patient A’s vector was created without knowing their creatinine level. Patient B’s vector was created with only one piece of information. The model does not break or require modification. It works with whatever data is available [4];
- Similarity-based reasoning: the magic happens when you compare patient vectors. The vector for Patient B is a component of the vector for Patient A. Mathematically, this means that their two vectors have a high degree of similarity. Thus, in general, you can find patients with similar clinical profiles by simply looking for vectors having high cosine similarity. Note that hdlib provides a dist function as Vector’s instance method to perform the cosine distance between the specific instance vector and a different Vector object, defined as 1 minus the cosine similarity. Following the previous example shown in Code 3, we can compute the cosine distance between patient_A and patient_B vectors using hdlib as: patient_A.dist(patient_B, method=“cosine”) [24].
Tip 2: For Genomics and Proteomics – Leverage Permutations to Encode Sequences
Encoding Positions


Which Method Should You Choose?
- Choose method 1 if your primary task is querying by position. For instance, if you frequently need to ask questions like “what nucleotide is at position 257?”, method 1 excels because you can directly query the full sequence vector with the position_257 vector to retrieve the answer;
- Choose method 2 if your goal is general sequence comparison, alignment, or if you need to ask questions like “at what positions does Adenine (“A”) appear?”. This approach is more elegant and memory efficient and requires a smaller codebook.
Tip 3: For Medical Imaging – Combine Vector-Symbolic Architectures with Convolutional Neural Networks for Explicable Artificial Intelligence
Building a Queryable Scene Description
- CNN acts as a junior technician. It has incredible eyes and can spot thousands of tiny, low-level patterns (textures, edges, shapes) in an image but cannot articulate what they mean;
- VSA acts as a senior pathologist. It takes the technician’s findings, gives them symbolic names (e.g., “spindle-shaped cells”, “high nuclear density”), notes their locations, and assembles everything into a structured, queryable report.
- Discover feature groups: we first run a clustering algorithm (like K-Means) on all the feature vectors produced by the CNN from a training set of images. This groups the thousands of slightly different numerical feature vectors into a small number of distinct clusters. Each cluster represents a recurring visual pattern, like a certain texture or cell shape;
- Assign symbolic names: we then treat each cluster as a single, unified concept. We assign a symbolic name to each one and generate a unique, random hypervector for each of these symbolic names in our codebook.


Why This Works

Tip 4: For Biosignal Processing (EEG/ECG) – Encode Time-Frequency Data Symbolically
A Symbolic Snapshot of the Signal’s State


Why This Works
- Create a prototype: collect many brain_state_hv samples while a subject is focused and bundle them together to create a single prototype_focused vector. Do the same for the relaxed state to create prototype_relaxed;
- Classify new data: to classify a new, unseen brain_state_hv after following the same encoding steps of a single test sample, simply check whether it is more similar to the focused or relaxed prototype (see Code 9 for a pseudocode using hdlib).

Tip 5: For Molecular Structures – Decompose Molecules into Atomic Fragments
A Sum of Its Parts
- o oxygen fragment: one central oxygen atom connected to two hydrogens via single bonds;
- o hydrogen fragment: each hydrogen is connected to one oxygen via a single bond.


Why This Works
Tip 6: For Biomedical Knowledge Graphs – Use Binding to Represent Relational Triples
Facts as Vectors


Why This Works

Tip 7: For Classification Tasks – Build and Refine Prototype Vectors
Learning the Average Case


Why This Works
- Simplicity and speed: the training phase is just one pass of addition. The prediction phase is just a few similarity calculations. This is orders of magnitude faster than training a deep neural network;
- Excellent for few-shot learning: this method creates a reasonable prototype even with just a few samples per class;
- Incremental learning/unlearning: if you get new labeled data, you do not have to retrain your model from scratch. You can simply update the existing prototype sums with the new vectors, allowing your model to learn continuously. Conversely, if data needs to be removed, the update is just a subtraction from the prototype.
Tip 8: For Data Fusion – Map All Modalities into a Common Vector Space
A Universal Language
- Encode each modality separately into its own hypervector using the most appropriate technique (e.g., methods from Tip 1 for text/EHRs, Tip 2 for genetic sequences, Tip 3 for images);
- Bundle the resulting vectors together to create a single, multimodal hypervector that represents the complete picture.


Why This Works
Tip 9: For Interpreting Results – Probe Composite Vectors with Clean Pointers
Asking Your Vector Questions

Tip 10: For Reproducibility and Impact – Practice Open Science
- Ensure others can easily discover your work: assign a Digital Object Identifier (DOI) to your code and data by using a repository like Zenodo or Figshare. This makes them easily citable. Also, use rich metadata and keywords when you upload your assets. Describe what the data contains, the VSA parameters used, and the context of the study;
- Make your research available to everyone: publish your code in a public repository like GitHub or GitLab. Submit your manuscript to a fully Open Access Journal to remove paywalls. The protocol for accessing the data should be open and free;
- Ensure your data and models can be combined with other tools and datasets: use common, standard file formats for your input data instead of proprietary formats. Clearly document your VSA parameters, especially the dimensionality and the vector type. This allows others to integrate your hypervectors with their own VSA-based tools;
- Enable others to effectively build upon your work: provide clear and comprehensive documentation. A README.md file in your code repository should explain what the project does and how to run the analysis, including listing all necessary software libraries and their version. Choose a permissive open-source license (e.g., MIT or Apache 2.0) that explicitly tells others how they are allowed to reuse your code.
Conclusions
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
Abbreviations
| AI | Artificial Intelligence |
| CNN | Convolutional Neural Network |
| DOI | Digital Object Identifier |
| ECG | Electrocardiography |
| EEG | Electroencephalography |
| EHR | Electronic Health Record |
| EMG | Electromyography |
| FAIR | Findability, Accessibility, Interoperability, and Reusability |
| HDC | Hyperdimensional Computing |
| MAP | Multiply-Add-Permute |
| MRI | Magnetic Resonance Imaging |
| VSA | Vector-Symbolic Architecture |
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