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#70196 - 2002-09-24 03:42 PM Floating Point - Should this simple expression work ?
Shawn Shawn Administrator Registered: 1999-08-13 Posts: 8611	Probably going to make an ass of myself here - and I know (think) this has been discussed before, but I just want to nail these floating point rules down ... Shouldn't this expression produce the number 300: ? 600 * 0.5 I know theres a bunch of funky rules about this ... but thought (intuitively) that this would have worked. -Shawn
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#70197 - 2002-09-24 03:45 PM Re: Floating Point - Should this simple expression work ?
Sealeopard Sealeopard KiX Master Registered: 2001-04-25 Posts: 11165 Loc: Boston, MA, USA	Nope, since the first value is integer, the second value will betreated as integer, too. So, since the integer value of 0.5 is 0, you'll get 0 as answer. However if you try 0.5 * 600 you'll get 300 because the first number is a float. In this case, the results are actually consistent with the KiXtart documentation. _________________________ There are two types of vessels, submarines and targets.
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#70198 - 2002-09-24 03:46 PM Re: Floating Point - Should this simple expression work ?
Lonkero Lonkero KiX Master Guru Registered: 2001-06-05 Posts: 22346 Loc: OK	still, jens is right but the integer value of 0.5 should be turned to 1... according to math rules... _________________________ ! download KiXnet
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#70199 - 2002-09-24 03:47 PM Re: Floating Point - Should this simple expression work ?
Shawn Shawn Administrator Registered: 1999-08-13 Posts: 8611	So then why does this not work: ? 0.0 + (600 * 0.5)
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#70200 - 2002-09-24 03:48 PM Re: Floating Point - Should this simple expression work ?
Jack Lothian Jack Lothian MM club member Registered: 1999-10-22 Posts: 1169 Loc: Ottawa,Ontario, Canada	If I understand the rules, kixtart looks at the type of first variable & this sets the tone for processing the statement. Thus it does integer math here. Reverse the order & it will do floating point. PS: The second formula doesn't work because as jooel says inside brackets the rules get applied from scratch. (I guess I should take time to read.) [ 24. September 2002, 15:56: Message edited by: Jack Lothian ] _________________________ Jack
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#70201 - 2002-09-24 03:49 PM Re: Floating Point - Should this simple expression work ?
Lonkero Lonkero KiX Master Guru Registered: 2001-06-05 Posts: 22346 Loc: OK	shawn, because it first count the stuff in paranthesis. jack, getting slow today? {edit} shawn, try it with: ? (0.0 + 600) * 0.5 [ 24. September 2002, 15:51: Message edited by: Lonkero ] _________________________ ! download KiXnet
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#70202 - 2002-09-24 03:51 PM Re: Floating Point - Should this simple expression work ?
Jack Lothian Jack Lothian MM club member Registered: 1999-10-22 Posts: 1169 Loc: Ottawa,Ontario, Canada	I am drinking coffee, & relaxing at this moment any small delay gets allows you guys to respond 10 times. _________________________ Jack
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#70203 - 2002-09-24 03:54 PM Re: Floating Point - Should this simple expression work ?
Sealeopard Sealeopard KiX Master Registered: 2001-04-25 Posts: 11165 Loc: Boston, MA, USA	Lonkero: The conversion will go towards the nearest even integer for exact fractions of .5. Try this: code: ? 0 + 0.5 ? 0 + 1.5 ? 0 + 2.5 ? 0 + 3.5 the results will be 0,2,2,4 This is documented in the KiXtart 4.11 Manual under CINT(). _________________________ There are two types of vessels, submarines and targets.
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#70204 - 2002-09-24 03:55 PM Re: Floating Point - Should this simple expression work ?
Shawn Shawn Administrator Registered: 1999-08-13 Posts: 8611	yes - reversing the order works nicely with numbers returned from COM objects: $DomainList.Right = 0.30 * $Form.ClientWidth thanks guys.
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#70205 - 2002-09-24 03:55 PM Re: Floating Point - Should this simple expression work ?
Sealeopard Sealeopard KiX Master Registered: 2001-04-25 Posts: 11165 Loc: Boston, MA, USA	Math Rules don't apply in the KiXtart Universe This might actually imply that we can develop a working warp drive if we stay within the KiXtart Universe _________________________ There are two types of vessels, submarines and targets.
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#70206 - 2002-09-24 03:56 PM Re: Floating Point - Should this simple expression work ?
Richard H. Richard H. Administrator Registered: 2000-01-24 Posts: 4946 Loc: Leatherhead, Surrey, UK	Because each expression is considered on it's own merits, and the 6000.5 expression will be evaluated before the 0.0+() expression. (0.0+600)0.5 should give you 300 though. We went through this pretty exhaustively with some good examples, but for the life of me I can't get the search engine to turn them up Beware however that one of the release candidates had a bug in the precedence when using "NOT" {edit} Good grief! a veritable flood! {/edit} [ 24. September 2002, 15:58: Message edited by: Richard Howarth ]
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#70207 - 2002-09-24 03:58 PM Re: Floating Point - Should this simple expression work ?
Jack Lothian Jack Lothian MM club member Registered: 1999-10-22 Posts: 1169 Loc: Ottawa,Ontario, Canada	Shawn, You notice the attention you get! Moth's to a flame. _________________________ Jack
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#70208 - 2002-09-24 03:59 PM Re: Floating Point - Should this simple expression work ?
Shawn Shawn Administrator Registered: 1999-08-13 Posts: 8611	yeah - my take was that if an expression starts with a floating point number - it would return a floating point - and likewise, if it started with an integer, return a integer (yada-yada). But what I didn't understand was that if an expression starts with an integer - any floating point number contained within are rounded up. -Shawn [ 24. September 2002, 16:01: Message edited by: Shawn ]
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#70209 - 2002-09-24 04:02 PM Re: Floating Point - Should this simple expression work ?
Lonkero Lonkero KiX Master Guru Registered: 2001-06-05 Posts: 22346 Loc: OK	btw, noticed that shawn is again the #1 poster on this board... MCA's vacation had some influence after all _________________________ ! download KiXnet
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#70210 - 2002-09-24 04:04 PM Re: Floating Point - Should this simple expression work ?
Jack Lothian Jack Lothian MM club member Registered: 1999-10-22 Posts: 1169 Loc: Ottawa,Ontario, Canada	Kixtart processes math expressions in a strictly left to right progression & at each step it converts the rightmost to variable type of the leftmost but as Jooel says brackets are processed first & inside the brackets the same left to right rules are followed & after the bracket is evaluated it returns to its left to right processing. PS: I thought kixtart followed the standard rules for conversion from floating point to integer - it truncates. Sorry I am so slow, but I am at work & distractions keep coming along. [ 24. September 2002, 16:12: Message edited by: Jack Lothian ] _________________________ Jack
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#70211 - 2002-09-24 04:14 PM Re: Floating Point - Should this simple expression work ?
Richard H. Richard H. Administrator Registered: 2000-01-24 Posts: 4946 Loc: Leatherhead, Surrey, UK	quote: Kixtart processes math expressions in a strictly left to right progression Not quite right, this is only true where the operators have the same precedence. KiXtart obeys standard operator preference, so in the expression: code: "10" + 5 * 2.5 = "1010" Will give the result "1010", as the multiplication will be evaluated first due to operator precedence. As the first number is an integer "5", the "2.5" is converted to an integer and the multiplication takes place, resulting in an integer "10". Now, the addition may take place and the result is a string, because the first element in the expression is a string. This means a catenation "10" + "10" = "1010"
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#70212 - 2002-09-24 04:29 PM Re: Floating Point - Should this simple expression work ?
Jack Lothian Jack Lothian MM club member Registered: 1999-10-22 Posts: 1169 Loc: Ottawa,Ontario, Canada	True, the complexities of precedence can seriously complicate an expression. _________________________ Jack
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#70213 - 2002-09-24 04:33 PM Re: Floating Point - Should this simple expression work ?
Bryce Bryce KiX Supporter Registered: 2000-02-29 Posts: 3167 Loc: Houston TX	Since it was not mentioned.... Use the command CDBL to convert a single int to a double. ? cdbl(2) * 3.2 ? cdbl(600) * 0.5
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#70214 - 2002-09-24 05:10 PM Re: Floating Point - Should this simple expression work ?
Shawn Shawn Administrator Registered: 1999-08-13 Posts: 8611	Bryce - good one - I was trying this: ? cdbl(600 * 0.5) Well, I appreciate the rational and justification Ruud used in building these rules - the jist of which is to maintain 100% backward compatibility with older scripts. The goal i guess was to insure that legacy scripts would never return a float - under any circumstance. But having said that - i don't see the harm in relaxing the rules so that if an expression "CONTAINED" a float - that the float wouldn't be rounded up. But I guess older scripts could potentially accidently read a float within an expression ... say, a string from a text file or from the registry ... not too sure about that. [ 24. September 2002, 17:11: Message edited by: Shawn ]
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#70215 - 2002-09-24 05:29 PM Re: Floating Point - Should this simple expression work ?
Jack Lothian Jack Lothian MM club member Registered: 1999-10-22 Posts: 1169 Loc: Ottawa,Ontario, Canada	You are starting to track into one of the key issues in Golf24 - ensuring kixtart consistently used floating point. It is a complex issue. _________________________ Jack
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