Beyond Distance: Engineering Similarity and Clustering in Non-Euclidean Graph Systems on GCP
Decisions, Not Models · Issue #4 · · Kutluk Atalay
In our previous issues, we established the foundational pillars of modern Graph AI systems. We transitioned from flat feature spaces to relational intelligence with Graph Neural Networks (GNNs), operationalized real-time inference through serverless orchestration, and resolved Temporal Data Slippage using Vertex AI Feature Store to align our models with reality.
We now possess something powerful: a living, temporally consistent graph. But this introduces a more fundamental challenge. A graph at scale—billions of nodes, trillions of edges—is not inherently insightful. Without structure, it is noise. Without segmentation, it is unusable.
At Informatiqs, we now confront a critical question:
How do we extract meaning from relational chaos?
In this fourth installment, we go beyond Euclidean intuition and re-engineer one of machine learning’s most fundamental operations—clustering. We will bridge theory and production by redefining similarity in graph systems, translating embeddings into actionable segments, and operationalizing this pipeline end-to-end on Google Cloud Platform (GCP).
1. The Euclidean Trap: When Distance Stops Meaning Anything
Traditional clustering algorithms—such as K-Means—are built on a silent assumption: distance defines similarity.
In Euclidean space, this works. If two customers are close in terms of age, income, or transaction frequency, grouping them is mathematically and intuitively valid. But graph systems break this assumption completely.
Two nodes may be identical in feature space yet occupy entirely different positions in the network. Conversely, nodes with no shared attributes may play identical structural roles.
In a fraud detection graph:
- Two accounts with different geographies and behaviors may both function as transaction hubs
- Two identical-looking accounts may belong to completely disconnected ecosystems
The failure here is not algorithmic—it is conceptual. We are attempting to apply geometric reasoning to topological systems. This is the Euclidean Trap.
And escaping it requires a shift from:
- What a node is → to
- How a node behaves within a network
2. From Distance to Structure: Embeddings as Behavioral Identity
We cannot cluster raw graph structures directly at scale. Instead, we must translate topology into a form that preserves its meaning. This is achieved through graph embeddings.
Using GNN-based message passing, each node is transformed into a dense vector that encodes:
- Its neighborhood
- Its connectivity patterns
- Its role within the global graph
This is not feature compression—it is behavioral encoding. Once in this latent space, similarity must also be redefined:
- Structural Equivalence → Nodes that play similar roles (e.g., hubs, bridges)
- Homophily → Nodes that belong to the same dense communities
Instead of relying on raw Euclidean distance, we move toward orientation-based similarity:
- Cosine similarity captures alignment of structural behavior
- Neighborhood-based metrics reflect relational overlap
At this stage, algorithms like K-Means or density-based methods become viable again—but only because we have reconstructed meaning in latent space.
3. Clusters vs. Communities: A Critical Distinction
One of the most common misconceptions in Graph ML is treating clusters as ground truth structures. They are not.
In graph systems:
- Communities are real, topology-driven structures
- Clusters are algorithmic approximations of those structures in embedding space
This distinction matters.
A poorly designed embedding pipeline can produce mathematically clean clusters that have no correspondence to real network behavior. A well-designed system, however, produces clusters that map to:
- Fraud rings
- Product ecosystems
- Influence networks
- Supply chain tiers
At Informatiqs, the architectural decision is not “which clustering algorithm to use,” but:
“Does this segmentation reflect the actual structure of the system?”
4. Orchestrating Similarity on GCP: From Embeddings to Decisions
Turning graph clustering into an enterprise capability requires more than algorithms—it requires architecture.
On GCP, this process must be explicitly decoupled into layers:
4.1. Embedding Generation (Vertex AI + BigQuery)
Graph data stored in BigQuery is processed through Vertex AI pipelines to generate embeddings. This step encodes relational intelligence into a scalable representation.
4.2. Scalable Clustering (BigQuery ML)
Instead of exporting data, clustering is executed directly within BigQuery using BQML. This avoids unnecessary data movement and enables segmentation at petabyte scale.
4.3. The Data Mart Layer (Decision Interface)
Raw embeddings and graph structures are not suitable for business consumption.
They must be transformed into a Data Mart:
- Cluster-labeled entities
- Aggregated community metrics
- Domain-specific abstractions
This is where complexity is translated into clarity.
4.4. BI & Operationalization (Looker)
Through semantic modeling, BI tools like Looker expose these clusters as:
- “High-propagation customer groups”
- “Price-insensitive communities”
- “Anomalous structural clusters”
The non-Euclidean complexity disappears.
What remains is decision-ready intelligence.
5. Sectoral Application: Dynamic Pricing as a Network Problem
Consider Dynamic Pricing Analytics.
Traditional systems treat customers and products as independent entities. But in reality:
- Products are linked through substitution and co-purchase behavior
- Customers are linked through influence and shared patterns
- Pricing changes propagate through the network
A GNN-based system clusters this ecosystem based on interaction topology, not static features.
This reveals:
- Product clusters that behave as unified demand systems
- Customer communities that amplify pricing signals
- Bridge nodes that connect otherwise isolated markets
When these clusters are pushed into a Pricing Data Mart and surfaced via Looker:
- Demand shocks become visible in real time
- Cross-category elasticity emerges naturally
- Pricing strategies become network-aware, not reactive
This is the shift from:
- Pricing as optimization → to
- Pricing as graph orchestration
6. The MLOps Reality: Drift, Stability, and Interpretability
Clustering in dynamic graphs is not a one-time computation—it is a continuously evolving system.
This introduces three critical challenges:
6.1. Embedding Drift
As the graph evolves, node representations shift. This can invalidate previously learned clusters.
6.2. Cluster Volatility
Nodes may frequently switch clusters, destabilizing downstream systems.
6.3. Interpretability Drift
The meaning of a cluster may change over time, even if its label remains constant.
To manage this, production systems must implement:
- Incremental embedding updates
- Temporal smoothing of cluster assignments
- Versioned clustering pipelines
- Monitoring for structural shifts
The objective is not to prevent change—but to ensure it is controlled, observable, and explainable.
7. The Discipline of “No”: When Clustering Fails
In line with our philosophy, we must emphasize restraint.
Not every graph contains meaningful communities.
If:
- Connections are sparse or noisy
- Relationships are not semantically meaningful
- The downstream decision does not require segmentation
Then clustering introduces artificial structure.
A clean architecture is not defined by how much it does—but by what it refuses to do.
Conclusion: From Geometry to Meaning
With this issue, we complete another critical layer in the Informatiqs framework:
- We moved from relational data → to embeddings
- From embeddings → to similarity
- From similarity → to clustering
- From clustering → to decision systems
This is the true evolution of enterprise AI.
We are no longer grouping data points. We are interpreting systems of interaction.
Because in complex networks, similarity is not about closeness. It is about function, influence, and position within a living structure.
In our next issue, we will go beyond structure into attention and importance. We will explore Graph Attention Networks (GATs) and how models learn to prioritize critical relationships in noisy, high-dimensional graphs.
What defines similarity in your current systems—and is it capturing structure, or just distance?