In addition to basic arithmetic operations like adding, subtracting, multiplying, and dividing, there are several advanced functions that can be used in the equation editor. They are described in detail below.
| Function | Description | Syntax | Notes | Examples |
|---|---|---|---|---|
| max of 2 | Returns the largest value in a set of arguments | maximum(a_1, a_2) | Arguments can be a variable, a constant, or a mathematical function of two or more variables | MAX (variable1, variable2) MAX (variable1, 100) MAX (variable1 - variable2, 0) |
| min of 2 | Returns the smallest value in a set of arguments | minimum(a_1, a_2) | Arguments can be a variable, a constant, or a mathematical function of two or more variables | MIN (variable1, variable2) MIN (variable1, 100) MIN (variable1 - variable2, 0) |
| frequency (s) | Returns the frequency of the variable in seconds | frequency |
The frequency of the variable is set in the "Edit" menu and can have values of 1 minute, five minutes, quarter hourly, etc. Mathematical operations can be performed on the frequency function. For example, 2*frequency will double the result of the frequency function. |
If the virtual variable has a Frequency set to 1 minute, the frequency function will return 60. If the virtual variable has a Frequency set to hourly, the frequency function will return 3600. |
| abs | Returns the absolute value of the expression | abs(a_1) | Arguments can be variables, constants, or mathematical functions of two or more variables | ABS (variable1) ABS (variable1 - variable2) ABS (variable1 - 500) |
| clip | Removes the values outside a specified boundary defined by a minimum and maximum limit | clip(a_1, a_min, a_max) | Argument a_1 is the variable of interest. Arguments a_min and a_max represent the upper and lower bounds to restrict argument a_1. Arguments a_min and a_max can be variables or constants. | CLIP (variable1, 25, 50) CLIP (variable1, variable2, 100) |
| sign | Evaluates the sign of an argument. Returns a 1 for positive values, returns a -1 for negative values, returns a 0 for zero values |
sign(a_1) | Arguments can be a variable, a constant, or a mathematical function. When the argument is a variable, the SIGN function is only valid when the display Frequency matches the variable Frequency |
SIGN (variable1) SIGN (variable1 + 1,000,000) SIGN (variable1 - variable2) SIGN (8.6) = 1 SIGN (-12) = -1 |
| ceil | Returns the next integer, rounded up. Positive numbers round up away from zero; negative numbers round up toward zero | ceil(a_1) | Arguments can be a variable, a constant, or an equation. | CEIL (variable1) CEIL (2*variable1 + variable2) CEIL (2.001) = 3 CEIL (-2.1) = -2 CEIL (-10.9) = -10 |
| round | Returns the rounded values of an argument to a specified number of decimal places | round(a_1,num_digits) | Arguments can be a variable, a constant, or an equation. The second argument, num_digits, specifies the number of decimal points to be kept when rounding. The default number is zero. | ROUND (variable1) ROUND (2*variable1 + variable2, 1) ROUND (15.21654984, 3) = 15.217 ROUND (2.8) = 3 |
| floor | Returns the next integer, rounded down. Positive numbers round down toward zero; negative numbers round down away from zero | floor(a_1) | Arguments can be a variable, a constant, or an equation. | FLOOR (variable1) FLOOR (2*variable1 - variable2) FLOOR (6.5) = 6 FLOOR (-6.5) = -7 |
| gradient | Returns a partial derivative at each point | gradient(a_1) | Arguments can be variables or equations containing variables. The gradient is calculated using the central finite difference model, which takes the difference in the two y-axis values on either side of the point of interest divided by the difference between the two x-axis values on either side of the point of interest. Gradient at x2 = (y3 - y1) / (x3 - x1) |
GRADIENT (variable1) |
| exp | Returns the value of the natural exponential function raised to the power of the argument. | exp(a_1) | Arguments can be a variable or a constant. The constant e equals approximately 2.718, the base of the natural logarithm. |
EXP (variable1) EXP (1) = 2.718 EXP (0) = 1 |
| log | Returns the value of the logarithm of the argument | exp(a_1, [a_2]) | Arguments can be a variable or a constant. Argument a_2 sets the base of the log function. An argument for the base is optional, and if omitted, it is assumed to be e. |
LOG (variable1) LOG (variable1, 10) LOG (EXP (variable1)) = variable1 LOG (1) = 0 LOG (10) = 2.3 LOG (10, 10) = 1 |