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Documentation Index

Fetch the complete documentation index at: https://docs.veydra.io/llms.txt

Use this file to discover all available pages before exploring further.

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Overview

Veydra supports importing system dynamics models from tools that export to the XMILE standard. XMILE (XML Interchange Language for System Dynamics) is an open standard that enables model portability across different system dynamics platforms.
Supported Tools: Stella Architect, Stella Professional, Vensim, and any software that exports valid XMILE format.

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Supported File Formats

ExtensionDescription
.xmileStandard XMILE XML format
.stmxStella model files
.xmlGeneric XML with XMILE structure
.mdlVensim model definition files

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Model Elements Converted

The XMILE parser extracts and converts:
  • Stocks - Accumulator variables with initial values
  • Flows - Rate variables connecting stocks
  • Auxiliaries - Helper variables and calculations
  • Modules - Submodels with their connections
  • Simulation Settings - Time units, start/stop times, and time step (DT)

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Function Support

Common system dynamics functions are automatically translated:
XMILE FunctionDescription
PULSEGenerate pulse at specified time
STEPStep function
RAMPLinear ramp
DELAY1, DELAY3First and third-order delays
SMOOTH, SMOOTHIExponential smoothing
MIN, MAX, ABSBasic math functions
IF THEN ELSEConditional logic
TIMECurrent simulation time

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How to Import

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From the Web App

  1. Navigate to your project or create a new one
  2. Click Import Model or use the Upload XMILE option
  3. Select your .xmile, .stmx, .xml, or .mdl file
  4. Provide a name for your model (optional - defaults to filename)
  5. Click Upload
The conversion runs automatically and creates:
  • A new project (if needed)
  • A model in Design Mode ready for editing
  • A linked GitHub repository for version control

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Via API

curl -X POST https://api.veydra.io/model/upload-xmile \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -F "file=@your_model.stmx" \
  -F "model_name=My System Dynamics Model" \
  -F "description=Imported from Stella"
Response: 
{
  "model_id": 12345678,
  "project_id": 87654321,
  "repository_url": "https://github.com/veydra-models/model-12345678",
  "message": "XMILE file uploaded successfully. Conversion job started."
}

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Conversion Process

+-------------------+     +------------------+     +-------------------+
|   Upload XMILE    | --> |   Parse & Validate   | --> |   Convert to VMS  |
|   (.stmx, .xml)   |     |   Extract elements   |     |   Python format   |
+-------------------+     +------------------+     +-------------------+
                                                            |
                                                            v
                          +------------------+     +-------------------+
                          |   Ready to Run   | <-- |   Create Model    |
                          |   in Playground  |     |   & Repository    |
                          +------------------+     +-------------------+

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After Import

Once converted, your model:
  • Opens in Design Mode - Review and edit the model structure
  • Has a GitHub Repository - Version control is automatically set up
  • Can be Simulated - Switch to Run Mode to execute simulations
  • Supports Collaboration - Share and collaborate with team members

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Troubleshooting

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Invalid XMILE File Error

The file must contain valid XMILE XML with either:
  • A <xmile> root element, or
  • A <model> element
Ensure your source tool exports in XMILE format, not a proprietary binary format.

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Unsupported Functions

If your model uses functions not in the supported list, they may need manual adjustment after import. The conversion will preserve the original equation text for review.

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Complex Module Structures

Models with deeply nested modules are supported but may require verification after import. Check the stock-flow diagram in the Model Playground to confirm connections are correct.

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XMILE Standard Reference

For technical details about the XMILE format, see the official OASIS specification: XMILE v1.0 Specification