Mathematical Expressions
ProcessDB supports the mathematics described on this page which include symbolic operators and functions as well as discrete events (which may create discontinuities in variables to represent biological or experimental events).
Operator precedence is the same in ProcessDB as it is in other tools using mathematical expressions. Any ambiguity will be clarified here as it is discovered. Parenthesis may be used in expressions to explicitly control the order of evaluation.
Supported Symbolic Operators and Functions
The following may be used anywhere a mathematical expression may appear in ProcessDB. They may not be used where a numerical constant is required, though a numerical constant may be used where a mathematical expression is required (just like a square is a rectangle but not all rectangles are squares - a constant is a mathematical expression, but not all mathematical expressions are constants).
Some places mathematical expressions may be used are in the Rate Law Dialog, a Model Realization Function, an Event Expression, an MOE Function, to name a few.
| Symbol | Name | Example | Result |
|---|---|---|---|
| + | Addition | NH2 + 3 | |
| - | Subtraction | NH2 - 3 | |
| * | Multiplication | NH2 * 3 | |
| / | Division | NH2 / 3 | |
| ^ | Power | NH2 ^ 3 | |
| ** | Power | NH2 ** 3 | |
| sqrt() | Square Root | sqrt(NH2) | |
| sin() | Sine | sin(NH2) | |
| cos() | Cosine | cos(NH2) | |
| exp() | Exponential (e^x) | exp(NH2) | |
| log() | Natural Logarithm | log(NH2) | |
| log10() | Log base 10 | -log10(Hplus) | |
| abs() | Absolute value | abs(NH2) | |
| int() | Integer part | int(1.5) | 1 |
Discrete Events
Discrete Events may not appear anywhere an expression appears. Instead, their use is restricted to the protocols of experiments. They will appear, however, in the MOE Equations as expressions that will be read by the Simulator and executed.
Most ProcessDB Discrete Events are triggered at a specific time and execute a particular assignment based on the Experimental Protocol at that time. Triggers may also be defined by an arbitrary conditional expression using the following operators, and events may execute an arbitrary mathematical assignment.
Parenthesis may be used to control the order of evaluation. Standard operator precedence is used otherwise.
| Symbol | Name |
|---|---|
| = | Equal To |
| ! | Not |
| < | Less Than |
| <= | Less Than or Equal To |
| > | Greater Than |
| >= | Greater Than or Equal To |
| <> | Not Equal To |