Available Expressions

This page provides the complete syntax reference for writing metric formulas, guard conditions, and parameter expressions in Jupiter.

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Numbers and Literals

• Use standard decimal digits with a period (.) as the separator: 5, 0.643, 1250.0.
• Do not use commas for decimals (0,5 triggers a syntax error).
• Do not use scientific notation: Forms like 1e-6 are not accepted. Write full decimal values: 0.000001.

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Place and Parameter Identifiers

• Places: Prefix the place name with # (e.g., #Queue, #InService, #Slots).
• Parameters: Enter the parameter name directly without symbols (e.g., SERVICE_TIME, WORKERS).
• Case Sensitivity: Identifiers are case-sensitive (Queue and queue refer to different nodes).

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Arithmetic Operators

Operator	Operation	Example
+	Addition	E{#Queue} + E{#InService}
-	Subtraction and negation	CAPACITY - E{#Queue}, -RATE
*	Multiplication	E{#Rate} * 100
/	Division	E{#InService} / SERVICE_TIME
( )	Grouping parentheses	(E{#Queue} + E{#InService}) * ARRIVAL_DELAY

Unsupported Math Operators

Exponents (^), square roots (sqrt), and modulo (%) are not supported. To calculate the square of a quantity $A$, multiply it by itself: A * A.

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Relational and Logical Operators

Used inside P{ }, within conditional IF blocks, and in transition guards:

Operator	Meaning	Example
> and >=	Greater than, greater or equal	#Queue > 0
< and <=	Less than, less or equal	#Slots <= 5
= or ==	Equal to	#Worker = 0
!=	Not equal to	#Queue != 0
AND	Logical AND (both must hold)	(#Queue > 0) AND (#Worker = 0)
OR	Logical OR (at least one holds)	(#Error > 0) OR (#Timeout > 0)
NOT	Logical NOT (inverts boolean value)	NOT (#Slots > 0)

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Conditional Expressions (IF ... THEN ... ELSE)

The ternary conditional structure dynamically selects values based on conditions:

IF condition THEN value_if_true ELSE value_if_false

This is the standard technique for guarding divisions against potential zeros:

IF E{#Completed} > 0 THEN E{#Queue} / E{#Completed} ELSE 0

Conditional blocks may be nested:

IF A > 10 THEN 100 ELSE IF A > 5 THEN 50 ELSE 0

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Built-in Mathematical Functions

The calculation engine provides three core utility functions:

Function	Behavior	Example
abs(x)	Returns absolute value of $x$	abs(E{#QueueA} - E{#QueueB})
min(a, b)	Returns the lesser of $a$ and $b$	min(E{#Queue}, ALERT_LIMIT)
max(a, b)	Returns the greater of $a$ and $b$	max(E{#Queue} - CAPACITY, 0)

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Handling Division by Zero

When a formula denominator evaluates to zero, the engine halts with:

NON_FINITE_METRIC: metric 'X' produced a non-finite value (Infinity/NaN)

This prevents corrupted metrics from silently polluting results.

Prevention Strategies

1. Guard with IF:

   IF throughput > 0 THEN items_in_system / throughput ELSE 0

2. Rewrite with Known Parameters: Instead of dividing by an instantaneous measured throughput that might fluctuate near zero during transient startup, multiply by the known arrival delay parameter:

   (E{#Queue} + E{#InService}) * ARRIVAL_DELAY

   Because ARRIVAL_DELAY is a strictly positive constant, this formulation is mathematically immune to division-by-zero errors.

Next steps

Explore the four core performance metrics, starting with Throughput.