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Standard Mangrove operators

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map

Use map as a lookup node in nexus_nodes_attributes: the child gives the lookup key, and the map node resolves that key through a resource parameter table. 
- name: Some mapped value
  operator: map
  nexus_resources_library: My Library
  nexus_resources_parameter: My Parameter
  nexus_nodes_attributes:
    - name: Lookup key input
      data_point_type: some-key-slug

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Complex expressions

Mangrove uses the Keisan expression language to evaluate mathematical and logical expressions within model nodes. This allows you to write complex formulas directly in the operator field of a node.

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Basic Syntax

Expressions are written as strings in the operator field of a calculated node. Child node values are referenced by their slugified names (lowercase, underscores instead of spaces). 
- name: Calculated Value
  operator: "child_a * child_b + 100"
  nexus_nodes_attributes:
  - name: Child A
    data_point_type: input-a-slug
  - name: Child B
    data_point_type: input-b-slug

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Notable Operators

Standard operators supported in the equations are listed here. These include:
  • Arithmetic operators
  • Comparison operators
  • Logical operators (e.g. &&)
  • Built-in mathematical functions (e.g. the below list)
    • abs(x): Absolute value
      Example: abs(-5) → 5
    • sqrt(x): Square root
      Example: sqrt(16) → 4
    • exp(x): Exponential (e^x)
      Example: exp(1) → 2.718...
    • log(x): Natural logarithm
      Example: log(10) → 2.302...
    • sin(x), cos(x), tan(x): Trigonometric functions
      Example: sin(0) → 0
    • round(x): Rounds a value. Use round(x) for nearest integer or round(x, n) for n decimal places.
      Example: round(10/2, 2) → 5.00
  • Conditional logic Example: if(condition, value_if_true, value_if_false)
  • List functions that work with arrays of values
    • max(list) — Maximum value in a list
    • min(list) — Minimum value in a list
    • range(n) — Generate list [0, 1, ..., n-1]
    • range(start, end) — Generate list from start to end-1
    • round — Rounds a value. Use round(x) for nearest integer or round(x, n) for n decimal places.
    • map — Maps a value from a linked library
    • duration — Converts the time range of the incoming datapoint into a duration
    • data_point_proportion — Extracts the allocation proportion from an allocated node

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When to Use Mangrove Operators vs Keisan Expressions

Use Mangrove operators when…Use Keisan expressions when…
Simple arithmetic on all childrenComplex multi-step formulas
Standard aggregations (sum, avg, max)Conditional logic (if/else)
Clearer, more readable modelsCustom rounding or transformations

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Best Practices

  1. Keep expressions simple — Break complex calculations into multiple nodes rather than one long expression. This improves readability and makes debugging easier.
  2. Use explicit unit conversions — Create separate nodes for unit conversions rather than embedding them in expressions.
  3. Name child nodes clearly — Since expressions reference child nodes by slugified name, use descriptive names that make the expression readable.
  4. Test your expressions — Use the Model Editor’s test functionality to verify calculations with sample inputs before saving.

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Further Reading