brycewang-stanford/algorithm-visualizer-guide

Algorithm Visualizer Guide

Overview

Algorithm Visualizer is an interactive online platform with over 48K stars on GitHub that allows researchers, educators, and students to visualize algorithms through animated graphical representations. The platform provides a web-based environment where algorithm code runs step-by-step alongside a visual canvas that shows data structures being manipulated in real time.

For academic researchers, Algorithm Visualizer serves two primary purposes. First, it is an excellent tool for teaching computational methods in courses and workshops. Complex algorithms in sorting, graph theory, dynamic programming, and numerical methods become immediately intuitive when students can see the step-by-step execution animated on screen. Second, researchers developing new algorithms can use the platform to debug, validate, and communicate their approaches visually, making it easier to explain novel computational contributions in papers and presentations.

The platform supports JavaScript-based algorithm implementations and provides a visualization API with tracer objects for arrays, graphs, logs, and custom 2D canvases. Researchers can create custom visualizations of their own algorithms and share them through the platform's public repository or embed them in course materials.

Platform Architecture and Setup

Algorithm Visualizer consists of three main components that work together to provide the interactive visualization experience.

Components

• algorithm-visualizer - The web application frontend (React-based)
• server - The backend API that compiles and executes code
• algorithms - The public repository of contributed algorithm visualizations

Running Locally for Research Use

# Clone the repository
git clone https://github.com/algorithm-visualizer/algorithm-visualizer.git
cd algorithm-visualizer

# Install dependencies
npm install

# Start development server
npm start

# Access at http://localhost:3000

Self-Hosted Deployment for Lab or Course

# Clone all required components
git clone https://github.com/algorithm-visualizer/algorithm-visualizer.git
git clone https://github.com/algorithm-visualizer/server.git

# Build and run with Docker
cd server
docker build -t algo-viz-server .
docker run -d -p 8080:8080 algo-viz-server

cd ../algorithm-visualizer
# Set the server URL in environment configuration
echo "REACT_APP_API_URL=http://localhost:8080" > .env.local
npm install && npm run build
npx serve -s build -l 3000

Visualization API for Custom Algorithms

The platform provides tracer objects that researchers use to instrument their algorithm code with visual output.

Array Tracer for Sorting and Searching

const { Tracer, Array1DTracer, LogTracer, Layout, VerticalLayout } = require('algorithm-visualizer');

// Set up visualization layout
const arrayTracer = new Array1DTracer('Array');
const logger = new LogTracer('Execution Log');
Layout.setRoot(new VerticalLayout([arrayTracer, logger]));

// Example: Visualizing insertion sort on research ranking data
const impactFactors = [3.2, 1.8, 7.5, 2.1, 5.9, 4.3, 6.7, 0.9];
arrayTracer.set(impactFactors);
Tracer.delay();

for (let i = 1; i < impactFactors.length; i++) {
    const key = impactFactors[i];
    let j = i - 1;

    logger.println(`Inserting element ${key} at position ${i}`);
    arrayTracer.select(i);
    Tracer.delay();

    while (j >= 0 && impactFactors[j] > key) {
        arrayTracer.patch(j + 1, impactFactors[j]);
        Tracer.delay();

        impactFactors[j + 1] = impactFactors[j];
        arrayTracer.depatch(j + 1);
        j--;
    }

    impactFactors[j + 1] = key;
    arrayTracer.patch(j + 1, key);
    Tracer.delay();
    arrayTracer.depatch(j + 1);
    arrayTracer.deselect(i);
}

logger.println('Sorting complete: journals ranked by impact factor');

Graph Tracer for Network Algorithms

const { Tracer, GraphTracer, LogTracer, Layout, VerticalLayout } = require('algorithm-visualizer');

const graphTracer = new GraphTracer('Citation Network');
const logger = new LogTracer('BFS Traversal');
Layout.setRoot(new VerticalLayout([graphTracer, logger]));

// Adjacency matrix representing citation relationships
const citations = [
    [0, 1, 1, 0, 0, 0],
    [0, 0, 1, 1, 0, 0],
    [0, 0, 0, 0, 1, 0],
    [0, 0, 0, 0, 1, 1],
    [0, 0, 0, 0, 0, 1],
    [0, 0, 0, 0, 0, 0]
];

const paperNames = ['Paper A', 'Paper B', 'Paper C', 'Paper D', 'Paper E', 'Paper F'];

graphTracer.set(citations);
Tracer.delay();

// BFS to find citation chains
function bfs(startNode) {
    const visited = new Set();
    const queue = [startNode];
    visited.add(startNode);

    logger.println(`Starting BFS from ${paperNames[startNode]}`);
    graphTracer.visit(startNode);
    Tracer.delay();

    while (queue.length > 0) {
        const current = queue.shift();

        for (let neighbor = 0; neighbor < citations.length; neighbor++) {
            if (citations[current][neighbor] === 1 && !visited.has(neighbor)) {
                visited.add(neighbor);
                queue.push(neighbor);

                logger.println(`${paperNames[current]} cites ${paperNames[neighbor]}`);
                graphTracer.visit(neighbor, current);
                Tracer.delay();
            }
        }
    }

    logger.println(`BFS complete. Visited ${visited.size} papers.`);
}

bfs(0);

Research-Relevant Algorithm Categories

The platform includes visualizations across categories directly relevant to computational research.

Graph Algorithms (Network Analysis)

• Breadth-First Search / Depth-First Search - Traversing citation networks, dependency graphs
• Dijkstra / Bellman-Ford - Shortest paths in weighted collaboration networks
• Minimum Spanning Tree (Kruskal, Prim) - Finding minimum-cost network connections
• Topological Sort - Ordering tasks in experimental pipelines
• Strongly Connected Components - Identifying tightly coupled research clusters

Sorting and Searching (Data Processing)

• Merge Sort / Quick Sort - Efficient sorting of large experimental datasets
• Binary Search - Fast lookup in ordered measurement arrays
• Heap Sort - Priority queue operations for scheduling simulations

Dynamic Programming (Optimization)

• Longest Common Subsequence - Sequence alignment in bioinformatics
• Knapsack Problem - Resource allocation under constraints
• Edit Distance - String similarity measures for text analysis

Numerical Methods

• Newton's Method - Root finding for equation solving
• Monte Carlo Simulation - Stochastic estimation of integrals and probabilities
• Gradient Descent - Parameter optimization in model fitting

Creating Custom Visualizations for Teaching

Researchers teaching computational courses can create custom algorithm visualizations and organize them into course-specific collections.

// Template for a custom research algorithm visualization
const {
    Tracer, Array1DTracer, Array2DTracer,
    LogTracer, Layout, VerticalLayout
} = require('algorithm-visualizer');

// Initialize tracers for your algorithm
const matrixTracer = new Array2DTracer('Distance Matrix');
const logger = new LogTracer('Algorithm Steps');
Layout.setRoot(new VerticalLayout([matrixTracer, logger]));

// Set initial data
const data = [
    [0, 3, 8, Infinity, -4],
    [Infinity, 0, Infinity, 1, 7],
    [Infinity, 4, 0, Infinity, Infinity],
    [2, Infinity, -5, 0, Infinity],
    [Infinity, Infinity, Infinity, 6, 0]
];

matrixTracer.set(data);
logger.println('Floyd-Warshall: Computing all-pairs shortest paths');
Tracer.delay();

// Floyd-Warshall algorithm with visualization
for (let k = 0; k < data.length; k++) {
    logger.println(`Intermediate vertex: ${k}`);
    for (let i = 0; i < data.length; i++) {
        for (let j = 0; j < data.length; j++) {
            if (data[i][k] + data[k][j] < data[i][j]) {
                data[i][j] = data[i][k] + data[k][j];
                matrixTracer.patch(i, j, data[i][j]);
                Tracer.delay();
                matrixTracer.depatch(i, j);
            }
        }
    }
}

logger.println('All-pairs shortest paths computed.');

Integration Tips for Researchers

• Course websites: Embed Algorithm Visualizer links directly in course syllabi and lab handouts
• Paper supplements: Create interactive algorithm demonstrations as supplementary material
• Lab meetings: Use visualizations to explain algorithmic approaches to interdisciplinary collaborators
• Self-hosted instances: Deploy within university networks for courses with restricted internet access
• Contributing back: Submit new algorithm visualizations to the public repository to share with the community

References

• Algorithm Visualizer website: https://algorithm-visualizer.org
• Algorithm Visualizer GitHub: https://github.com/algorithm-visualizer/algorithm-visualizer
• Algorithms repository: https://github.com/algorithm-visualizer/algorithms
• Visualization API documentation: https://github.com/algorithm-visualizer/algorithm-visualizer/wiki