Koder sim

Koder Sim

*rea:*Developer Platform
*ath:*koder-sim/
*ind:*Go simulation engine + REST/SSE server + Flutter visualization app
*ersion:*1.1.0
*tatus:*Active

Role in the stack

Koder Sim is a multi~~domain discrete~~event and compartmental simulation platform. It ships as a self~~contained Go binary (`sim~~server) exposing a REST API on port 8108, and a Flutter desktop app (koder-simapp`) for interactive visualization. Use cases: epidemiology modeling, queue theory, traffic flow, tournament generation, and Monte Carlo estimation.

Core capabilities

Capability	Details
Queue (MMc)	Discrete-event simulator; theoretical MM1 comparison
Epidemiology	SIR / SEIR compartmental model with vaccination, Euler integration
Tournament	Single, double~~elimination and round~~robin bracket generator
Traffic	Cellular automaton grid road network; per-step FlowMetrics
Monte Carlo	Parallel trial runner; configurable confidence intervals; histogram
SSE streaming	GET `/api/v1/simulate/{epi,traffic,montecarlo}/stream` — stepbystep events
Flutter app	Line charts, bar charts, bracket diagram, heatmap, histogram; CSVJSONPNG export

Primary couplings

Module	Relationship
`koder-sim/app/`	Flutter frontend; consumes REST + SSE from sim-server
None (standalone)	No auth, no external dependencies at runtime

Architecture

koder-sim/
  cmd/sim-server/      Go HTTP server — port 8108
  internal/
    engine/            Discrete-event engine (heap-based DES clock)
    epi/               SIR/SEIR compartmental models
    queue/             M/M/c queue simulator
    tournament/        Bracket generator
    traffic/           Grid road network + vehicle agents
    montecarlo/        Parallel Monte Carlo framework
  app/
    lib/
      core/            Theme, API base URL
      models/          Typed result classes per simulation type
      services/        SimService (HTTP + SSE), ExportService (CSV/JSON/PNG)
      screens/         HomeScreen, QueueScreen, EpiScreen, TournamentScreen,
                       TrafficScreen, MonteCarloScreen
      widgets/         SimLineChart, BracketWidget, HeatmapWidget, ExportBar

REST API

Method	Path	Description
GET	`/health`	Health check
POST	`/api/v1/simulate/queue`	MMc batch simulation
POST	`/api/v1/simulate/epi`	SIR/SEIR batch simulation
POST	`/api/v1/simulate/tournament`	Bracket generation
POST	`/api/v1/simulate/traffic`	Traffic flow batch
POST	`/api/v1/simulate/montecarlo`	Monte Carlo batch
GET	`/api/v1/simulate/epi/stream`	SSE — daybyday epi results
GET	`/api/v1/simulate/traffic/stream`	SSE — stepbystep traffic metrics
GET	`/api/v1/simulate/montecarlo/stream`	SSE — batched trial results

Changelog

Version	Date	Summary
1.1.0	20260422	Flutter visualization app; SSE streaming endpoints; HistBin.ConfLevel
1.0.0	20260402	Initial engine + REST API