Variable operations

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