E + E

NUMERIC

or

DATETIME

Addition of two expressions. The two arguments can be numeric or fully specified datetime expressions. If numeric expressions are used, they must be of the same unit type. See Mathematical Expressions Involving a Datetime Operand for details on using this operation with datetimes.

NUMERIC

or

DATETIME

Subtraction of two expressions. The two arguments can be numeric or fully specified datetime expressions. If numeric expressions are used, they must be of the same unit type. See Mathematical Expressions Involving a Datetime Operand for details on using this operation with datetimes.

NUMERIC

Multiplication of two numeric expressions.

NUMERIC

Division of two numeric expressions.

NUMERIC

Exponentiation of one numeric expression (the base) to a power of another numeric expression (the exponent). The exponent is truncated to an integer. (For non-integer exponents, use the Exp RPL Predefined Function; see Exp.) The units of the base are raised to the power of the exponent.

BOOLEAN

Logical validity check for numeric data types. The result is TRUE if the numeric expression evaluates to a NaN, i.e. Not a Number. The result is FALSE if the numeric expression has a value.

BOOLEAN

Logical AND comparison of two expressions. The result is TRUE if both expressions are TRUE. The result is FALSE if one expression is TRUE and the other is FALSE.

Note: If the first expression is FALSE, the entire AND is FALSE and the second expression is not evaluated.

BOOLEAN

Logical OR comparison of two expressions. The result is TRUE if either expression is TRUE. Otherwise it is FALSE.

BOOLEAN

Greater than comparison. The result is TRUE if the first expression is strictly greater than the second expression. Otherwise it is FALSE. The two arguments can be numeric expressions of the same unit type or datetime expressions (fully or partially specified). Numeric expressions are automatically converted to common units before comparison. A datetime expression is considered greater if it is later in time.

See below for more information on tolerance during the comparison.

BOOLEAN

Greater than or equal comparison. The result is TRUE if the first expression is greater than or equal to the second expression. Otherwise it is FALSE. The two arguments can be numeric expressions of the same unit type or datetime expressions (fully or partially specified). Numeric expressions are automatically converted to common units before comparison. A datetime expression is considered greater if it is later in time.

See below for more information on tolerance during the comparison.

BOOLEAN

Less than comparison. The result is TRUE if the first expression is strictly less than the second expression. Otherwise it is FALSE. The two arguments can be numeric expressions of the same unit type or datetime expressions (fully or partially specified) Numeric expressions are automatically converted to common units before comparison. A datetime expression is considered less than if it is earlier in time.

See below for more information on tolerance during the comparison.

BOOLEAN

Less than or equal to comparison. The result is TRUE if the first expression is less than or equal to the second expression. Otherwise it is FALSE. The two arguments can be numeric expressions of the same unit type or datetime expressions (fully or partially specified). Numeric expressions are automatically converted to common units before comparison. A datetime expression is considered less than if it is earlier in time.

See below for more information on tolerance during the comparison.

BOOLEAN

Equality comparison. The result is TRUE if the first expression is exactly equal to the second expression. Otherwise it is FALSE. The two arguments can be numeric expressions (not necessarily of the same unit type), fully or partially specified datetime expressions, object expressions, slot expressions, boolean expressions, string expressions, or list expressions. Numeric expressions of the same unit type are automatically converted to common units before comparison. A fully specified datetime expression can be compared to a partially specified datetime expression; in this case, only the largest time unit is compared.

See below for more information on tolerance during the comparison.

BOOLEAN

Inequality comparison. The result is TRUE if the first expression is not equal to the second expression. Otherwise it is FALSE. The two arguments can be numeric expressions of the same unit type, fully or partially specified datetime expressions, object expressions, slot expressions, boolean expressions, string expressions, and list expressions. Numeric expressions are automatically converted to common units before comparison. Datetime expressions are considered greater as they are later in time. A fully specified datetime expression can be compared to a partially specified datetime expression; in this case, only the largest time unit is compared.

See below for more information on tolerance during the comparison.

NUMERIC

Series slot value at a particular timestep or slot value at a particular row. The first unspecified <expr> must be completed by an expression which evaluates to a specific slot on an object. The second <expr> must be a fully specified datetime which lies on an increment of the model run timestep or a row on the slot.

NUMERIC

Table slot value in a particular row and column. The first unspecified <expr> must be completed by an expression which evaluates to a specific table slot on an object. The two comma-separated <expr> are the row and column of the table slot, respectively. The row and column may each be specified as:

OR

Agg series slot or periodic slot value for a particular date and a particular column. The first unspecified <expr> must be completed by an expression that evaluates to a specific slot on an object. The two comma-separated <expr> are the date and column of the slot, respectively. The column may be specified as a zero-based numeric value with units of [NONE] or a string expression which matches the column label. See Referencing Periodic Slots in RPL in User Interface for details.

NUMERIC

Series slot value at the current timestep or scalar slot value. The unspecified <expr> must be completed by an expression which evaluates to a specific slot on an object.

NUMERIC

NaNToZero <expr>

This operator has a single numeric sub expression; if that sub expression is a lookup of an invalid value (NaN), then NaNToZero evaluates to 0.0 in the units of the lookup slot, otherwise it simply returns the value unchanged. This operator provides a simple and efficient way to treat a missing slot value as zero, a common requirement of water accounting policy.

To illustrate, the following expression

is equivalent to

Note: Unlike the IsNaN operator, this operator is only useful when the sub-expression is an object/slot lookup expression; if any other type of numeric sub expression encounters a NaN during evaluation, then evaluation of the entire containing expression will halt as usual. For example, if we assume that "Res A.Outflow" has units of cms but has no valid values, then the expression

would evaluate to 0.0 [cms], but the expression

would not evaluate successfully; it would terminate when the invalid value on Res A was encountered.

SLOT

Object and slot expression. This expression can be used to specify the object and slot required by the three slot lookup/assignment expressions above. The object expression must be an object in the model and the string expression must be the name of a slot, exactly as it appears on the object.

SLOT

Object, account and accounting slot expression. This expression can be used to specify the object, account, and slot required by the three slot lookup/assignment expressions. The object expression must be an object in the model. The account is a string expression that returns the account name, for example “Contractor 1” The slot string expression must be the full name of an accounting slot, for example “Storage”.

This ternary operator is preferred in terms of readability and performance over the Obj ^ Acct & Slot operator listed below.

SLOT

Object and accounting slot expression. This expression can be used to specify the object and slot required by the three slot lookup/assignment expressions above. The object expression must be an object in the model and the string expression must be the full name of an accounting slot, in the form: “account name.slot name”, for example “Contractor 1.Storage”.

This operator was one of the original ways to specify an object, account and slot. Consider using the Obj ^ Acct . Slot ternary operator, described above, for improved performance and readability.

OBJECT

Invokes the object selector dialog.

This button invokes the object selector to choose a single object in the model.

STRING

Invokes the account selector dialog.

This button invokes the account selector to choose a single account as a string.

SLOT or STRING

Invokes the slot selector dialog.

This button invokes the slot selector to choose a slot. The slot can be on an object or on an account where applicable. In some contexts, the button evaluates to a string which represents the name of a slot, for example “Storage”.

NUMERIC

- <numeric expr>

Reverse the sign of a numeric expression. Magnitude and units are maintained, but a positive value becomes negative and a negative value becomes positive.

BOOLEAN

NOT <boolean expr>

Reverse the value of a boolean expression. TRUE becomes FALSE and FALSE becomes TRUE.

any

Adds a conditional expression with NO else clause. If the boolean expression evaluates to TRUE, the expression on the second line is evaluated. Otherwise it is not, and the entire conditional statement does not evaluate to a value.

any

Adds a conditional expression including an else clause. If the boolean expression evaluates to TRUE, the expression on the second line is evaluated. If the boolean expression evaluates to FALSE, the expression on the fourth line is evaluated. The entire conditional statement evaluates to one of the two expressions.

any

Adds an Else branch to a conditional expression. It is generated by highlighting the either the boolean condition <boolean expr> or consequence expression <expr> of an IF expression or ELSE IF expression and selecting the ELSE button.

If the boolean expression evaluates to FALSE, the expression on the fourth line is evaluated. The entire conditional evaluates to one of the two expressions.

any

Adds an ELSE IF branch to a conditional expression. It is generated by highlighting the boolean condition <boolean expr> or consequence <expr> of an IF or ELSE IF and selecting the ELSE IF button. The ELSE IF branch is added immediately after the branch containing the selection.

In the example above, if the first boolean expression evaluates to FALSE, the boolean expression on the third line is evaluated. If that boolean is true, the expression on the fourth line is evaluated. You may add as many ELSE IF branches as needed.

any

Structure for looping over the items in a list. The looping variable, index, is set to the value of the next item in the list expression each time through the loop. The value variable, result, is initialized on the first line of the structure. Each time through the loop, the expression on the second line is evaluated and its value is set on the result variable. The previous value of the result variable may be used inside the expression on the second line. The items in the list and the result may be of any expression type even though the default structure uses the numeric type for the looping variable and the result. To change the type of the looping variable, index, and/or the value variable, result, double-click the NUMERIC element and enter the new expression type. The names of the looping and value variables may also be changed.

There is also a FOR statement used to loop over a list and execute multiple statements. See RPL Statements for details.

any

Structure for defining a variable to be used multiple times within an expression. The variable, var, is set on the first line of the structure. This variable can be used as many times as desired within the expression(s) between the DO and END WITH. Because the variable is not recalculated each time it is used, this structure can make a block more efficient. The variable may be of any expression type even though the default structure uses the numeric type. To change the type of the variable, var, double-click the NUMERIC element and enter the new expression type. The name of the variable may also be changed.

There is also a WITH statement used to set a temporary variable outside of multiple statements. See RPL Statements for details.

any

Structure for looping as long as a condition is TRUE. The conditional boolean expression is evaluated prior to each loop. If the boolean expression is TRUE, the numeric expression on the second line is evaluated. If the boolean expression is FALSE, the structure stops looping and returns the value of the value variable. The value variable, result, is initialized on the first line of the structure. Each time through the loop, the expression on the second line is evaluated and its value is set on the result variable. The previous value of the result variable may be used inside the expression on the second line. The result may be of any expression type even though the default structure uses the numeric type. To change the type of the value variable, result, double-click the NUMERIC element and enter the new expression type. The name of the value variable may also be changed.

When a WHILE expression is executed, it counts the number of times the body is evaluated, and fails with a message if the iteration count ever exceeds the value of the RPL parameter. The default max iterations is 10,000, but may be modified as needed in the RPL Parameters dialog. (From the main workspace, select Policy, then RPL Parameters to open the parameters).

NUMERIC

Specialized FOR loop structure for looping over the items in a list and summing a variable. For each item in the list, the looping variable, index, is set to the value of the next item in the list expression. Next, the expression on the second line is evaluated and its value is added to the result variable. The items in the list may be of any expression type even though the default structure uses the numeric type for the looping variable and the result. To change the type of the looping variable, index, double-click the NUMERIC element and enter the new expression type. The names of the looping variables may also be changed.

NUMERIC

Specialized FOR loop structure for looping over the items in a list and averaging their values. For each item in the list, the looping variable, index, is set to the value of the next item in the list expression. Next, the expression on the second line is evaluated and its value is included in the total resulting average. The items in the list may be of any expression type even though the default structure uses the numeric type for the looping variable and the result. To change the type of the looping variable, index, double-click the NUMERIC element and enter the new expression type. The names of the looping variable may also be changed.

LIST

This button creates a list with a single item of an unspecified type.

any

This button adds a new item of an unspecified type to an existing list. To use it, highlight one item and select the button. The new item is added immediately after the highlighted item in the list.

LIST

The set difference expression takes two lists and returns a single list that contains the items that are in the left hand list but not in the right hand list. Duplicate items are removed.

LIST

The set symmetric difference expression takes two lists and returns a single list that contains the items that are not in both lists. This is equivalent to the expression: (list1 U list2) - (list1 intersect list2). This is also equivalent to the expression: (list1 - list2) U (list2 - list1). Duplicate items are removed.

LIST

The set union expression takes two lists and returns a single list that contains the items that are in either list or both lists. Duplicate items are removed.

LIST

The set intersection expression takes two lists and returns a single list that contains the items that are in both lists. Duplicate items are removed.

any

Evaluates to the expression located at the given numeric index in the given list. The index numeric expression is zero-based and has units of [NONE]. If the item at the given index in the list is not the expected type when the expression is evaluated or if there is no item at the given index in the list, the run aborts with an error.

LIST

Insertion of a new item of unspecified type into the first location of an existing list. If the list is initially empty, the new list contains only one item. If the list initially contains items, all items are shifted down to allow the new item to be inserted at the front of the list.

NUMERIC

Determines the number of items in the list expression. The numeric value has units of [NONE].

LIST

Append a new item of unspecified type onto the end of an existing list. If the list is initially empty, the new list contains only one item. If the list initially contains items, the new item is appended as the last item of the list.

BOOLEAN

Tests for existence of the given expression as a member of the list expression. If the given expression is one of the items in the list, this function evaluates to TRUE. If the expression does not match any of the items of the list, the function is FALSE.

LIST

Creates a list of datetimes beginning with the first datetime expression and ending on or before the second datetime expression. The datetime arguments must be fully specified. The interval between datetime items of the list is equal to the run timestep (or the slot’s timestep for an expression slot). If the second datetime argument does not correspond to a model run timestep, the last item of the list is the last model run timestep before the argument.

LIST

Removes the item at a given index from an existing list. All of the items which followed the removed item in the list are shifted up. If there is no item at the given index when the expression is evaluated, the run aborts with an error.

LIST

Substitutes the item at a given index in an existing list with the given expression. If there is no item at the given index when the expression is evaluated, the run aborts with an error.

NUMERIC

This is used to find the index of a given item in a list. If the item is not contained in the list, -1 (negative one) is returned.

LIST

This expression is used to take a list and perform some action to each element in the list thereby resulting in a new, modified list. This expression was developed primarily for performance reasons. Prior to the existence of this function, the user would use a FOR loop to rotate through the elements of a list, modify them, and create a new list with the modified elements. With the MAP LIST expression, this is much more efficient and more readable.

LIST

or

STRING

Concatenates two expressions into one. If the two expressions are of type LIST, the resulting expression is a single list containing all of the items of the two original lists. The order of the items is preserved, with the first list’s items before the second list’s items. If the two expressions are of any other type, the resulting expression is a string made up by concatenating the STRINGIFY’d second expression onto the end of the STRINGIFY’d first expression. See the description of STRINGIFY below.

Note: It is not necessary to explicitly STRINGIFY an expression before using it in a CONCAT expression. If the expression is not already a STRING, it will be automatically converted. Thus,

is equivalent to

but the first expression is cleaner and more efficient

any

Adds parenthesis around any expression. Parenthesis can make complicated expressions more readable. Parenthesis may also be required to remove ambiguity in the order of expression evaluation.

STRING

Converts any expression into a string. The STRING representations of other expression types are:

Aborts the Run

This operator takes any expression type as an argument. When it is evaluated, it aborts the run with an error message which contains the argument as part of the message. If executed from within an iterative MRM rule, it aborts the MRM run.

comment

Inserts a user specified in-line comment above the selected RPL expression or RPL statement. A separate dialog is opened that allows the user to type in a comment. In the RPL editor, the comment is displayed with # characters on the left, lines wrapped as they were in the comment editor dialog, and text in red (or user-specified comment color; see Colors). Double-clicking the comment reopens the edit dialog.

For a given RPL dialog, the inline comments can be hidden or shown using the View, then Show Comments menu or by checking the Show: Comments toggle at the bottom of the dialog.

Deletes comment

Deletes the selected comment. Comments can also be deleted by selecting the comment, then using the Edit, then Delete menu or pressing Delete.