VALUE TYPES

Integer

• Numeric for whole numbers
• Range: -billion to billion (normal 32 bits)
• Held as: 32 bits
• Coding: simple signed binary number

Floating point

• Numeric for floating point numbers
• Range: normal 32 bits
• Held as: 32 bits
• Coding: normal exponent and mantissa

Ratio

• Numerator and denominator, both can be signed
• Used for any ratio
• Range: Each part has range of full integer.
• The ratio can represent infinity by holding denominator = 0
• Held as: Two 32 bit integers
• Coding: Two simple signed binary numbers; Infinity when denominator = 0
• In most manipulations, the greatest common divisor is removed (so if you multiply 4/7 by 14/15 you get 8/15)

Odds

• Numerator and denominator, both positive
• Used especially for odds and conversions to and from probability
• Used for bayesian multipliers
• Range: Each part has range 0 to 65k
• Held as: Two unsigned 16 bit words
• Coding: Two simple unsigned binary numbers; Infinity when denominator = 0
• In most manipulations the greatest common divisor is removed

String

• Any string
• Range: up to 200 characters in length at present
• Held as: child 'Sysatt' block with as much space as needed
• Coding: ASCII

Boolean

• Truth value: yes or no, true or false
• Range: true or false
• Held as: unsigned 16 bit word
• Coding: 0 = false, anything else = true

Probability

• 0 to 1 (0 to 100%) for soft truth value
• Range: 0 to 1
• Held as: Unsigned 16 bit word
• Coding: 0x0000 means 0, 0xffff means 1

Bayesian

• Probability used for evidential reasoning
• Has a-priori and lower and upper cut-offs
• Range: Part as probability
• Held as: Four probabilities
• Coding: As probability, four times

Proportion

• Represents a proportion 0 to 100%
• Used for anything that requires a limit of 100%
• Range: 0 to 100%
• Held as: Unsigned 16 bit word
• Coding: 0xffff means 100%
• In many things proportion and probability are interchangeable

OZMO

(one-zero-minus-one, e.g. result of cosine)
• Like a proportion that can go negative as well as positive
• Used for e.g. degrees of belief, degrees of dislike
• Range: -1 to 0 to 1
• Held as: Signed 32 bit word,
• Coding: 0x80000000 means -1, 0 means 0, 0x7fFFffFF means 1

Direction/Angle

(0 to 360 degrees)
• A circular value which represents proportion round a circle
• Used for angles, directions, etc.
• Range: 0 to 360 degrees (2.pi radians)
• Held as: Unsigned 16 bit word
• Coding: 0x0000 = 0 and 360 degrees. 0xffff = just before 360, 90 degrees = 0x4000, 180 degrees = 0x8000, etc.

Enumerated Type

• An index number for selecting an entity from a set
• See also Ordinal, which is ordered
• Strictly, numeric comparisons and operations meaningless, but in practice allowed as for Ordinal
• Range: strictly meaningless
• Each value is expected to have an attached string name
• Held as: Unsigned 16 bit word
• Coding: 0 means 'nothing selected', 1 upwards shows selection

Ordinal

• An index number for selecting an entiry from a list
• See also Enum, which is unordered
• Numeric comparisons and operations meaningful
• Range: 1 to 65k
• Each value can be linked to an attached string name
• Held as: Unsigned 16 bit word
• Coding: 1 = first in list, 2 = second, etc. 0 = 'nothing selected'

Block

• The DSAP of a block in the KB
• Used for identifying things in the KB and e.g. getting name of it
• Its value must never be altered as it is like a pointer
• Range: strictly meaningless
• Coding: 32 bit relative pointer