Language Reference 1

+

DESCRIPTION: The addition operator, "+"

USAGE:

  x=Expr+Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value of the expression is the sum of two expressions

Example 1:

  x=1+2
   =3

SAMPLE MODELS: <links to sample models where this function is used>

-

DESCRIPTION: The subtraction operator

USAGE:

  x=Expr-Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value of the first expression minus the value of the second expression

Example 1:

  x=15-2
   =13

SAMPLE MODELS: <links to sample models where this function is used>

*

DESCRIPTION: The multiplication operator

USAGE:

  x=Expr*Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value is the product of two expressions

Example 1:

  x=5*4
   =20

SAMPLE MODELS: <links to sample models where this function is used>

/

DESCRIPTION: The division operator

USAGE:

  x=Expr/Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value of the first expression divided by value of the second expression

Example 1:

  x=60/6
   =10

SAMPLE MODELS: <links to sample models where this function is used>

^

DESCRIPTION: The power operator

USAGE:

  x=Expr^Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: The first expression to the power of the value of the second expression

Example 1:

  x=7^3
   =343

SAMPLE MODELS: <links to sample models where this function is used>

%

DESCRIPTION: The percentage operator

USAGE:

      x=Expr % Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value of the first expression modulo the value of the second expression(assumes that the values of the expression are integers

SEE ALSO: <a link to the composite functions section of seles modellers guide>

Example 1:

          x=19 % 12
           =7

Example 2:

          x=10 % 20
           =10

Example 3:

          x=10 % 10
           =0

SAMPLE MODELS: <links to sample models where this function is used> Model Builder's Guide Chapter 9#Continuous Functions (Arithmetic Functions)

==

DESCRIPTION: The EQ operator or the alternate form of EQ comparison (Note: two equal signs distinguish this from an assignment). This is a Boolean function operator.

USAGE:

  x=(Expr)==(Expr)=(Expr)EQ(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value on the left of the == or the EQ sign must equal to the value on the right of the == or the EQ sign.

Example 1:

  x=(|-9|)==(9) (TRUE)
   =1

Example 2:

  x=(2*8)==(4*4) (TRUE)
   =1

Example 3:

  x=(2*0)==(-1)  (FALSE)
   =0

Example 4:

x=(|-9|)EQ(9) (TRUE)
 =1

Example 5:

  x=(2*6)EQ(4*4) (FALSE)
   =0

SAMPLE MODELS: <links to sample models where this function is used>

!=

DESCRIPTION: The not equal operator or the alternate form of NOT EQUAL comparison. This is a Boolean function operator.

USAGE:

  x=(Expr)!=(Expr)=(Expr)NEQ(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value on the left of the != or NEQ sign does not equal to the value on the right of the != or NEQ sign.

Example 1:

  x=(|-9|)!=(-9)(TRUE)
   =1

Example 2:

  x=(2*8)!=(4*3) (TRUE)
   =1

Example 3:

  x=(2*8)!=(2*8) (FALSE)
   =0

Example 4:

x=(1+7)NEQ(8)(FALSE)
 =0

SAMPLE MODELS: <links to sample models where this function is used>

<

DESCRIPTION: A Boolean function operator that returns TRUE(1) if the value of the first expression is less than the value of the second expression; otherwise FALSE(0).

USAGE:

  x=(Expr)<(Expr)=(Expr)LESS THAN(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value on the left of the < or the LESS THAN is less than the value on the right of the < or LESS THAN sign

Example 1:

  x=(17)<(21) (TRUE)
   =1

Example 2:

  x=(-17)LESS THAN(-17) (FALSE)    
   =0

SAMPLE MODELS: <links to sample models where this function is used>

<=

DESCRIPTION: A Boolean function operator that returns TRUE(1) if the value of the first expression is less than or equal to the value of the second expression; otherwise FALSE(0).

USAGE:

  x=(Expr)<=(Expr)=(Expr)LESS OR EQUAL(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value on the left of the <= or LESS OR EQUAL sign is less or equal to the value on the right of the <= or LESS OR EQUAL sign

Example 1:

  x=17<=21 (TRUE)
   =1

Example 2:

  x=(-17)LESS OR EQUAL(|-17|) (TRUE)    
   =1

Example 3:

  x=-17<=-18 (FALSE)
   =0

SAMPLE MODELS: <links to sample models where this function is used>

>

DESCRIPTION: A Boolean function operator that returns TRUE(1) if the value of the first expression is greater than the value of the second expression; otherwise FALSE(0).

USAGE:

  x=(Expr)>(Expr)=(Expr)GREATER THAN(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value on the left of the > or GREATER THAN sign is greater than the value on the right of the > or GREATER THAN sign

Example 1:

  x=5>2 (TRUE)
   =1

Example 2:

  x=(5)GREATER THAN(5) (FALSE)
   =0

SAMPLE MODELS: <links to sample models where this function is used>

>=

DESCRIPTION: A Boolean function operator that returns TRUE(1) if the value of the first expression is greater than or equal to the value of the second expression; otherwise FALSE(0).

USAGE:

  x=(Expr)>=(Expr)=(Expr)GREATER OR EQUAL(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Value on the left of the >= or GREATER OR EQUAL sign is greater or equal to the value on the right of the >= or GREATER OR EQUAL sign

Example 1:

  x=5>=2 (TRUE)
   =1

Example 2:

  x=(5)GREATER OR EQUAL(5) (TRUE)
   =1

Example 3:

  x=5>=6 (FALSE)
   =0

SAMPLE MODELS: <links to sample models where this function is used>

!

DESCRIPTION: A Boolean function operator that negates the expression Boolean value.

USAGE:

  x=!Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Negates the expression Boolean value

Example 1:

  y = TRUE x=IF !y THEN 3 ELSE 4
    =4

SAMPLE MODELS: <links to sample models where this function is used>

ABS(Expr)

DESCRIPTION: The absolute value operator

USAGE:

  x=ABS(Expr)=|Expr|=ABSOLUTE(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Absolute value of the expression

Example 1:

  x=ABS(-12)==12 (TRUE)
   =1

Example 2:

  x=|-12|==12 (TRUE)
   =1

Example 3:

x=ABSOLUTE(-12)==12 (TRUE)
 =1

Example 4:

x=ABS(12)==57 (FALSE)
 =0

SAMPLE MODELS: <links to sample models where this function is used>

AND

DESCRIPTION: A boolean operator that returns TRUE if two expressions are both TRUE, and FALSE otherwise.

USAGE:

  x= Expr AND Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: TRUE (1) if all sub-expressions evaluate to TRUE and FALSE (0) otherwise

NOTES:

Example 1:

  x=(3>6) AND (14>9)
   =FALSE(0)

Example 2:

  x=(6>3) AND (14>9)
   =TRUE(1)

Example 3:

  x=10 AND (9<14)
   =10

Example 4:

  x=10 AND -5
   =-50

SAMPLE MODELS: <links to sample models where this function is used> Model Builder's Guide Chapter 9#Composite Functions

==ARCCOS==(Expr) inverse cos of the value of the expression Model Builder's Guide Chapter 9#Continuous Functions (Trigonometric Functions)

ARCCOS

DESCRIPTION: The arccos function operator

USAGE:

  x=ARCCOS(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Inverse cos of the value of the expression

Example 1:

  x=ARCCOS(0.5)
   =59.9999999999998

SAMPLE MODELS: <links to sample models where this function is used>

ARCSIN

DESCRIPTION: The arcsin function operator

USAGE:

  x=ARCSIN(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Inverse sine of the value of the expression

Example 1:

  x=ARCSIN(1)
   =89.9999999999998

SAMPLE MODELS: <links to sample models where this function is used>

ARCTAN(Expr)

DESCRIPTION: The arctan function operator

USAGE:

  x=ARCTAN(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Inverse tan of the value of the expression

Example 1:

  x=ARCTAN(1)
   =44.9999999999999

SAMPLE MODELS: <links to sample models where this function is used>

ARCTAN(Expr,Expr)

DESCRIPTION: The arcsin quadrant function operator

USAGE:

  x=ARCTAN(Expr,Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Inverse tan where first expression is x offset and second is y offset. Provideing two expressions gives more infomation about the quadrant

Example 1:

   x=ARCTAN(5,9)
    =60.9453959009227

SAMPLE MODELS: <links to sample models where this function is used>

BITWISE OR

(Expr, Expr) Bitwise OR of two valuesModel Builder's Guide Chapter 9#Bit-Vector Functions

BITWISE AND

(Expr, Expr) Bitwise AND of two valuesModel Builder's Guide Chapter 9#Bit-Vector Functions

BITWISE XOR

(Expr, Expr) Bitwise exclusive-OR of two valuesModel Builder's Guide Chapter 9#Bit-Vector Functions

BITWISE NOT

Expr	Bitwise NOT of a valueModel Builder's Guide Chapter 9#Bit-Vector Functions

CEILING(Expr)

DESCRIPTION: The ceiling operator

USAGE:

  x=CEILING(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Smallest integer larger than the expression value

Example 1:

  x=CEILING(0.01)
   =1

SAMPLE MODELS: <links to sample models where this function is used>

CLAMP

(Expr, MinExpr, MaxExpr)

DESCRIPTION: The clamp operator

USAGE:

  x=(Expr, MinExpr, MaxExpr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Clamp the value X of the expression to the range [Min, Max]: if X<Min then return Min; if X<Max return Max. Otherwise return X.

Example 1:

SAMPLE MODELS: <links to sample models where this function is used>

CLASSIFY

(X) if the value of the variable X is equal to one of CLASS Number: Expr the classes listed, then return the result of the. : associated expression. Otherwise return 0. Model Builder's Guide Chapter 9#Classified and Discrete Functions ENDFN Model Builder's Guide Chapter 9#Classified and Discrete Functions

CLASSIFY

(X) return the result of the kth expression in the list, Expr where k = X – minimum value of the variables

  :	(this may be non-0 only for layers)
  :

Model Builder's Guide Chapter 9#Classified and Discrete Functions ENDFN Model Builder's Guide Chapter 9#Classified and Discrete Functions

CLASSIFY

(X): ( Number+) return the kth number in the list, where k = X – minimum value of the variable (this may be non-0 only for layers)Model Builder's Guide Chapter 9#Classified and Discrete Functions

CLASSIFY

(X): Filename uses the table in the named file, which is assumed to consist of class:value pairs. Rarely used. Model Builder's Guide Chapter 9#Classified and Discrete Functions

CLASSIFY

(X): Filename Key uses the table in the named file, which is assumed to consist of class:value pairs. The key is used to specify a sub-table in a multi-table file. Rarely used.

Classified functions use the variable as an index into the list of numbers or expressions that follow. The “CLASS” keyword is optional. This variable must be non-negative. If “CLASS # :” is used, then the number refers to the value of the indexing variable. If a class is not specified for a given value, its expression is implicitly ZERO. Interpolation tables are very similar except that the variable is assumed to be continuous instead of classified. An interpolated value between classes is returned. Lookup tables are also similar, except that both the variable and classes are assumed to be continuous values. An interpolated value between classes is also returned. Rarely used. Model Builder's Guide Chapter 9#Classified and Discrete Functions

CLASSIFIED_DIST

draw a value from a discrete distribution, where CLASS Number: Expr each expression determines the relative : probability of its associated class being drawn. ENDFN The CLASS keyword is optional.

CLASSIFIED_DIST

( Number+) in this form, the classes are assumed to start at zero. Only constant probabilities can be given.

CLASSIFIED_DIST

in this form, the classes are assumed to start at Expr zero : ENDFN

CLASSIFIED_DIST[M]

In this form, the classes in a one-dimensional array M, and so start at zero.

COS

DESCRIPTION: The cos function operator

USAGE:

  x=COS(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Inverse cos of the value of the expression

Example 1:

  x=COS(0.5)
   =0.99996192306417

SAMPLE MODELS: <links to sample models where this function is used>

CRITICAL SECTION

(Flag) Enter (if Flag is TRUE) or exit (if Flag is FALSE) a critical section. A critical section gives priority to this application, and is used for synchronizing access to shared variables (i.e. shared with another application).Model Builder's Guide Chapter 9#Control Expressions

DEBUG

Update the simulation probe, if it is loaded and The event is selected. Used to debug/verify event behaviour.Model Builder's Guide Chapter 9#Control Expressions

DECISION

Expr approximation of line between end cells Cost surface and least-cost path regions are advanced features that are best understood with an example model. Model Builder's Guide Chapter 9#Region Functions

DECISION

Expr known location indices. If there is a decision expression, then only those cells for which this expression returns TRUE will be included. Model Builder's Guide Chapter 9#Region Functions

==DECISION== Expr location indices stored in one-dimensional X. Model Builder's Guide Chapter 9#Region Functions

==DECISION== Expr location index. If there is a decision expression, then only those cells for which this expression returns TRUE will be included. Model Builder's Guide Chapter 9#Region Functions

DECISION

Expr defines a region centred on the current cell. If there is a decision expression, then only those cells for which this expression returns TRUE will be included.

DistanceType is either CARDINAL or EUCLIDEAN (the default). Cardinal distance between two cells is the minimum number of cardinal steps (up, down, left, right) to reach one cell from the other. Euclidean distance is the straight-line distance between two points. The WRAPPED flag, if present indicates that the region wraps around the sides (vertically and horizontally) of the landscape (e.g. a location x positions beyond the right-hand side of a raster will be mapped to x positions in from the left-hand side of the raster). If not present, the landscape does not wrap. Model Builder's Guide Chapter 9#Region Functions DESCRIPTION: Defines a region centred on the current cell. If there is a decision expression, then only those cells for which this expression returns TRUE will be included.

USAGE:

  x= Expr AND Expr

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: TRUE (1) if all sub-expressions evaluate to TRUE and FALSE (0) otherwise

NOTES:

Example 1:

  x=(3>6) AND (14>9)
   =FALSE(0)

Example 2:

  x=(6>3) AND (14>9)
   =TRUE(1)

Example 3:

  x=10 AND (9<14)
   =10

Example 4:

  x=10 AND -5
   =-50

SAMPLE MODELS: <links to sample models where this function is used>

DIRECTION

(Expr, Expr) angle in degrees between two location indices Model Builder's Guide Chapter 9#Continuous Functions (Miscellaneous)

==DISPLAY== Display on the screen the labelled Label: Expr values computed with the expressions listed. …. If no label is given, the expression must ENDFN be a variable, and this is used for the label. Model Builder's Guide Chapter 9#Output Expressions DESCRIPTION: The clamp operator

DESCRIPTION: The clamp operator

USAGE:

  x=(Expr, MinExpr, MaxExpr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Clamp the value X of the expression to the range [Min, Max]: if X<Min then return Min; if X<Max return Max. Otherwise return X.

Example 1:

SAMPLE MODELS: <links to sample models where this function is used>

==DISPLAY== Same as above, but only display if the DECISION Expr decision expression evaluates to TRUE Label: Expr The keyword DECISION can be replaced by …. a “?” ENDFN Model Builder's Guide Chapter 9#Output Expressions OUTPUT RECORD(OutputVar) Output to the record file of output variable the labelled values computed with the Label: Expr expressions listed. If no label is given, the …. Expression must be a variable and this is ENDFN used as label. Model Builder's Guide Chapter 9#Output Expressions OUTPUT RECORD(OutputVar) Same as above, but only output if the DECISION Expr decision expression evaluates to TRUE Label: Expr …. ENDFN

DISTANCE

(Expr, Expr) distance between two location indices (normally obtained using the Location variable). Thus, DISTANCE(loc1, loc2) is sqrt(sqr(loc1.x – loc2.x) + sqr(loc1.y – loc2.y)) Model Builder's Guide Chapter 9#Continuous Functions (Miscellaneous)

ELSE

DESCRIPTION: A control expression that evaluates to TRUE and the set of sub-expressions after the ELSE otherwise.

USAGE:

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Expression evaluates to TRUE and the set of sub-expressions after the ELSE otherwise. Note that "ELSE IF expr" forms can be strung together.

Example 1:

SAMPLE MODELS: <links to sample models where this function is used>

EQUAL TRUE

(1) if the sub-expressions all evaluate to the same value and FALSE (0) otherwise Model Builder's Guide Chapter 9#Composite Functions

EXP(Expr)

DESCRIPTION: (Expr) base of the natural logarithm (e) to the power of the expression

USAGE:

  x=EXP(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Base of the natural logarithm (e) to the power of the expression

SEE ALSO: <a link to the composite functions section of seles modellers guide>

Example 1:

          x=EXP(3)
           =20.08553692

SAMPLE MODELS: <links to sample models where this function is used> Model Builder's Guide Chapter 9#Expressions:

FLOOR(Expr)

DESCRIPTION: The flooring operator

USAGE:

  x=FLOOR(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Largest integer smaller than the expression value

Example 1:

  x=FLOOR(0.99)
   =0

SAMPLE MODELS: <links to sample models where this function is used>

GEOMETRIC MEAN

geometric mean of the sub-expressions (nth root of the product for n expressions)

Model Builder's Guide Chapter 9#Composite Functions

GREATER OR EQUAL

TRUE (1) if the sub-expression evaluations are all ordered according to the relation >=, and FALSE (0) otherwise Model Builder's Guide Chapter 9#Composite Functions

GREATER THAN

TRUE (1) if the sub-expression evaluations are all ordered according to the relation >, and FALSE (0) otherwise

Model Builder's Guide Chapter 9#Composite Functions

File:Logarithms.png

Logarithms to various bases: red is to base e, green is to base 10, and purple is to base 1.7. Each tick on the axis is one unit. Note how logarithms of all bases pass through the point (1, 0). (This is so because any (nonzero) number raised to the power 0 is 1.)

The logarithm is the mathematical operation that is the inverse of exponentiation (raising a constant, the base, to a power). The logarithm of a number x in base b is the number n such that x = bⁿ. It is usually written as

\log_{b} (x) = n .

LOG(Expr)

DESCRIPTION: The logarithm operator

USAGE:

  x=LOG(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE:

3^{4} = 3 \times 3 \times 3 \times 3 = 81.

Natural logarithm of the value of the expression. This is a mathematical operation that is the inverse of exponentiation(raising a constant, the base, to a power) Ex:

\log_{3} (81) = 4,

Failed to parse (syntax error): {\displaystyle \4^3=81\,\! }

In this program, it is assumed that the base is 10, ie:

\log (10) = l o g_{1} 0 (10)

Note that the natural Logarithm is the inverse of the natural exponential function, ie: (x), which is the same as In(x) for all positive x and

Failed to parse (unknown function "\In"): {\displaystyle \In(e^x)=x \,\! }

for all real x. The only difference between Log and natural Log is their bases that Log uses 10 and natural Log uses e. For convenience,

\log_{e} (x)

is usually written in a different notation: In(x). SEE ALSO: Model Builder's Guide Chapter 9#Expressions:

Example 1:

  x=LOG(0.773)
   =-0.111820506

SAMPLE MODELS: <links to sample models where this function is used>

ROUND(Expr)

DESCRIPTION: The rounding operator

USAGE:

  x=ROUND(Expr)

REQUIRED ARGUMENTS: Expr is any expression that evaluates to single numeric value

VALUE: Expression value rounded to the nearest integer

Example 1:

  x=ROUND(0.773)
   =1

SAMPLE MODELS: <links to sample models where this function is used>