 YAP 7.1.0
Predicates that perform arithmetic

## ◆ is/2

 class is/2

is( X:number, + Y:ground)

properties: deterministic

This predicate succeeds iff the result of evaluating the expression Y unifies with X This is the predicate normally used to perform evaluation of arithmetic expressions:

X is 2+3*4

succeeds with `X = 14`

Consult Arithmetic Functions for the complete list of arithmetic_operators

## ◆ isnan/1

 class isnan/1

isnan(? X:float)

properties: deterministic

Interface to the IEE754 `isnan` test

## ◆ isinf/1

 class isinf/1

isinf(? X:float)

properties: deterministic

Interface to the IEE754 `isinf` test

## ◆ logsum/3

 class logsum/3

logsum(+ Log1:float, + Log2:float, - Out:float )

properties: deterministic

True if Log1 is the logarithm of the positive number A1, Log2 is the logarithm of the positive number A2, and Out is the logarithm of the sum of the numbers A1 and A2 Useful in probability computation

## ◆ between/3

 class between/3

between(+ Low:int, + High:int, ? Value:int)

properties: nondeterministic

Low and High are integers, High >= Low If Value is an integer, Low =< Value =< High When Value is a variable it is successively bound to all integers between Low and High If High is inf or infinite between/3 is true iff Value >= Low, a feature that is particularly interesting for generating integers from a certain value

## ◆ Yap_EvalError__()

 void Yap_EvalError__ ( const char * file, const char * function, int lineno, yap_error_number type, Term where, ... )

Definition at line 364 of file eval.c.

## ◆ Yap_InitEval()

 void Yap_InitEval ( void )

Definition at line 528 of file eval.c.

## ◆ Yap_InnerEval__()

 Term Yap_InnerEval__ ( Term t USES_REGS )

Definition at line 164 of file eval.c.

## Functions

Term Yap_InnerEval__ (Term t USES_REGS)

void Yap_EvalError__ (const char *file, const char *function, int lineno, yap_error_number type, Term where,...)

void Yap_InitEval (void)