Math Operations

Name	Math Operations
Version	v1.0.2
DockerHub	weevenetwork/math-operations
Authors	Jakub Grzelak

• Math Operations
  • Description
  • Supported Operations
  • Environment Variables
    • Module Specific
    • Set by the weeve Agent on the edge-node
  • Dependencies
  • Input
  • Output

Description

This module enables performing math operations on the data. Supported operations: + - * / % ^ ceil abs floor sqrt sin cos tan exp. Negative numbers must be put in brackets, i.e. (-9) or (-1.34). If you want to use received data, then refer to them in your calculations formula by placing their label in double curly brackets, i.e. if your data is { 'temperature': 12, 'volume': 3 } and want to use temperature in your calculations then refer to it as {{temperature}}

Sample calculations:

• {{temperature}} * 9 / 5 + 32
• 1/2 + (2 + 3) / (sin((-9) - 2)^2 - 6/7) - cos(1) + {{temperature}}
• {{temperature}} * {{volume}} / (-12)

Supported Operations

Operand	Description
+	Sum of two numbers.
-	Subtraction of two numbers.
*	Multiplication of two numbers.
/	Division of two numbers.
%	Modulus.
^	Power.
ceil(x)	Return the ceiling of x, the smallest integer greater than or equal to x.
abs(x)	Return the absolute value of x.
floor(x)	Return the floor of x, the largest integer less than or equal to x.
sqrt(x)	Return the square root of x.
sin(x)	Return the sine of x radians.
cos(x)	Return the cosine of x radians.
tan(x)	Return the tangent of x radians.
exp(x)	Return e raised to the power x, where e = 2.718281… is the base of natural logarithms.

Environment Variables

Module Specific

The following module configurations can be provided in a data service designer section on weeve platform:

Name	Environment Variables	type	Description
Formula	FORMULA	string	Build a mathematics formula using supported operations. To use data in your calculations refer to their labels in double curly brackets {{...}}.
Result Label	RESULT_LABEL	string	Assign calculations results to this label.
Action on Result	NEW_RESULT	string	What to do with the calculated results? Update result label? Output as stand alone data? Options: update or stand-alone. If selected update then calculated value will update value assigned to Result Label or append to the data object received by the module if Result Label is not present. If selected stand-alone then data received by the module will be disregarded and the module will output a new JSON object holding calculated value and assigned to Result Label

Set by the weeve Agent on the edge-node

Other features required for establishing the inter-container communication between modules in a data service are set by weeve agent.

Environment Variables	type	Description
MODULE_NAME	string	Name of the module
MODULE_TYPE	string	Type of the module (Input, Processing, Output)
EGRESS_URLS	string	HTTP ReST endpoints for the next module
INGRESS_HOST	string	Host to which data will be received
INGRESS_PORT	string	Port to which data will be received

Dependencies

bottle
requests

Input

Input to this module is:

• JSON body single object, example:

{
    "temperature": 12,
    "volume": 3
}

• array of JSON body objects, example:

[
    {
        "temperature": 12,
        "volume": 3
    },
    {
        "temperature": 10,
        "volume": 4
    },
    {
        "temperature": 1.3234,
        "volume": 3
    }
]

Output

If the following module configuration is provided FORMULA = {{temperature}} * 9/5 + 32, RESULT_LABEL = temperatureFahrenheit, NEW_RESULT = update then output of this module to the above input data will be:

• JSON body single object, example:

{
    "temperature": 12,
    "volume": 3,
    "temperatureFahrenheit": 53.6
}

• array of JSON body objects, example:

[
    {
        "temperature": 12,
        "volume": 3,
        "temperatureFahrenheit": 53.6
    },
    {
        "temperature": 10,
        "volume": 4,
        "temperatureFahrenheit": 50
    },
    {
        "temperature": 1.3234,
        "volume": 3,
        "temperatureFahrenheit": 34.38212
    }
]