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Math Formula (Variable)

KNIME Math Expression Node version 4.0.0.v201905311239 by KNIME AG, Zurich, Switzerland

This node evaluates a (free-form) mathematical expression based on the values of the flow variables. The computed results can be either appended as new variable or be used to replace an input variable. Commonly used functions are shown in the list "Mathematical Functions". There are also some constants available, such as pi (the ratio of the circumference of a circle to its diameter) and e (the base of the natural logarithms).

This node uses JEP, the Java Math Expression Parser.

You can reference the integer flow variables like this: $${IflowVar}$$, the floating point flow variables like this: $${DflowVar}$$.

NaN values act as value true in boolean expressions and compared to anything (including NaN) in any way (including ==, but not !=, which is like !(... == ...)) is false (0).

Please note the expressions are case sensitive.

Options

Flow Variable List: Available flow variables, which can be used as variables in the expression.
Category: The operator categories.
Function: A list of valid operators in the selected category.
Description: Short help about the operator.
Expression: The mathematical expression editor. You have completion available.
Append Variable: The name of the variable to append.
Replace Variable: The variable to be replaced.
Convert to Int: The result should be converted to an integer, or kept as a floating point number.

Input Ports

: (Optional) input variables

Output Ports

: Input variables with the new or replaced output variable.

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Workflows

Installation

To use this node in KNIME, install KNIME Math Expression (JEP) from the following update site:

KNIME 4.0

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