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Comparison tolerance: Difference between revisions
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(Created page with "'''Tolerant comparison''' is an inexact form of comparison used to mitigate the impact of floating-point rounding error on programs. It considers two numbers equal when their relative difference is smaller than a parameter called the '''comparison tolerance''', and accessed with the system variable <syntaxhighlight lang=apl inline>⎕CT</syntaxhighlight>. In addition to the comparison functions, tolerance applies to Match and Not Match, Floor, C...") |
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'''Tolerant comparison''' is an inexact form of [[comparison]] used to mitigate the impact of floating-point rounding error on programs. It considers two [[number]]s equal when their relative difference is smaller than a parameter called the '''comparison tolerance''', and accessed with the [[system variable]] <syntaxhighlight lang=apl inline>⎕CT</syntaxhighlight>. In addition to the comparison functions, tolerance applies to [[Match]] and [[Not Match]], [[Floor]], [[Ceiling]], and [[Modulus]], and [[search | '''Tolerant comparison''' is an inexact form of [[comparison]] used to mitigate the impact of floating-point rounding error on programs. It considers two [[number]]s equal when their relative difference is smaller than a parameter called the '''comparison tolerance''', and accessed with the [[system variable]] <syntaxhighlight lang=apl inline>⎕CT</syntaxhighlight>. In addition to the comparison functions, tolerance applies to [[Match]] and [[Not Match]], [[Floor]], [[Ceiling]], and [[Modulus]], and [[search function]]s defined in terms of Match (not [[Interval Index]]). | ||
{{quote|In an early talk Ken was explaining the advantages of tolerant comparison. A member of the audience asked incredulously, "Surely you don't mean that when <nowiki>A=B and B=C</nowiki>, A may not equal C?" Without skipping a beat, Ken replied, "Any carpenter knows that!" and went on to the next question.|—Paul Berry<ref>[[Roger Hui]]. [https://keiapl.org/anec/ Ken Iverson Quotations and Anecdotes]. 2005-09-30.</ref>}} | {{quote|In an early talk Ken was explaining the advantages of tolerant comparison. A member of the audience asked incredulously, "Surely you don't mean that when <nowiki>A=B and B=C</nowiki>, A may not equal C?" Without skipping a beat, Ken replied, "Any carpenter knows that!" and went on to the next question.|—Paul Berry<ref>[[Roger Hui]]. [https://keiapl.org/anec/ Ken Iverson Quotations and Anecdotes]. 2005-09-30.</ref>}} | ||
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== References == | == References == | ||
<references/> | <references/> | ||
{{APL built-ins}}[[Category:Function characteristics]][[Category:System constants]] | |||