Random numbers

Author(s): Daniel Cabeza.

Version: 1.11#222 (2004/5/24, 13:8:7 CEST)

Version of last change: 1.9#275 (2004/1/9, 16:25:9 CET)

This module provides predicates for generating pseudo-random numbers

• Usage and interface (random)
• Documentation on exports (random)

Usage and interface (random)

Documentation on exports (random)

PREDICATE: random/1:

random(Number)

Number is a (pseudo-) random number in the range [0.0,1.0]

Usage:

• The following properties should hold at call time: Number is a free variable. (term_typing:var/1)
• The following properties hold upon exit: Number is currently instantiated to a float. (term_typing:float/1)

PREDICATE: random/3:

random(Low, Up, Number)

Number is a (pseudo-) random number in the range [Low, Up]

Usage 1:

• Description: If Low and Up are integers, Number is an integer.
• The following properties should hold at call time: Low is an integer. (basic_props:int/1) Up is an integer. (basic_props:int/1) Number is a free variable. (term_typing:var/1)
• The following properties hold upon exit: Number is an integer. (basic_props:int/1)

Usage 2:

• The following properties should hold at call time: Low is a float. (basic_props:flt/1) Up is a number. (basic_props:num/1) Number is a free variable. (term_typing:var/1)
• The following properties hold upon exit: Number is a float. (basic_props:flt/1)

Usage 3:

• The following properties should hold at call time: Low is an integer. (basic_props:int/1) Up is a float. (basic_props:flt/1) Number is a free variable. (term_typing:var/1)
• The following properties hold upon exit: Number is a float. (basic_props:flt/1)

PREDICATE: srandom/1:

srandom(Seed)

Changes the sequence of pseudo-random numbers according to Seed. The stating sequence of numbers generated can be duplicated by calling the predicate with Seed unbound (the sequence depends on the OS).

Usage:

• Calls should, and exit will be compatible with: Seed is an integer. (basic_props:int/1)
• The following properties hold upon exit: Seed is an integer. (basic_props:int/1)

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