Allowed Operators

This article explains the allowed operators in Model Reef formulas.

You will learn:

• Which operators you can use.

• Which constructs are not supported.

• How to express logic using arithmetic only.

Model Reef uses an arithmetic only formula engine to keep models deterministic and vector friendly.

1

Supported operators

You can use the following operators:

• Addition: a + b

• Subtraction: a - b

• Multiplication: a * b

• Division: a / b

• Parentheses: (a + b) * c

These operators work on complete time series, not single cells. The engine applies them period by period across the model timeline.

2

Supported operands

Formulas can reference:

• Variables.

• Drivers (economic, operational, modifier).

• Imported series exposed in sidebars.

• Sometimes report lines or categories, depending on context.

All operands represent time series, so the operations are vectorised automatically.

3

Not supported

The following are not supported in formulas:

• IF statements or any conditional logic.

• Logical operators such as AND, OR or NOT.

• Cell style references like A1 or B5.

• Text functions or string concatenation.

• Aggregation functions over time such as SUM over a range, moving averages or lags.

This design avoids circular references and hidden complexity.

4

Expressing logic with arithmetic only

Common patterns expressed with arithmetic only include:

• Percentage based calculations

  • Margin % = (Revenue - COGS) / Revenue

• Growth or escalation

  • Future value = Base value * (1 + Growth driver)

• FX conversion

  • Local value = Foreign value * FX driver

• Scenario scaling

  • Scenario B = Scenario A * Scenario modifier driver

Careful structuring of variables and drivers lets you build complex models without conditional formulas.

5

Validation of operator use

The Formula editor validates:

• That only supported operators are used.

• That parentheses are balanced.

• That all references are to known series.

If an unsupported operator or construct appears, you will see an error message before saving.

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