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------- Additional comments from [EMAIL PROTECTED] Thu Feb 1 09:37:21 -0800 2007 ------- AW->richlv: Thanks for Your comments. Well, Yes, it goes in the right direction (so, no, no crap at all :-). Unfortunately, it's not about 'slightly deviate' but 'completely wrong' when calculations exceed the displayable limit. Let's make a decimal example. When You add any 2 single-digit numbers, the result may at maximum need two digits (9 + 9 -> 18). When You have three slots to remember the result, You may add up to (999 / 9) -> 111 single-digit numbers without danger. If You add more, Your result may be wrong (overrun), depending on the added numbers (not all need to be 9, but maybe). When multiplying, it gets worse. Potentially in binary space, You need double the space to be on the safe side. What happens often is something like scaling all values of e.g. a polygon. With integer numbers, the factor is normally a fraction, e.g. x / y. Multiplying with this fraction is: a = a * x / y Now an example with numbers, a = 250, x = 10, y = 3 (multiply with 3.333...). Expected integer-result is 833. But that's not what You get with limit to 3 digits: a * x -> 250 * 10 -> 2500, three digits -> truncated to 500 500 / 3 -> 166 The in-between result does not fit in the choosen number space. Dividing before multiplying looks like a good idea, but will make the result more unprecise: 250 / 3 -> 83, * 10 -> 830, three off from the expected result. For addition this means: errors with less numbers involved (e.g. center of polygon, all points get added and divided by count -> errors will happen with polygons which work today) For multiplication this means: The chance to get completely wrong results increases by the given factors. HTH. Comments? --------------------------------------------------------------------- Please do not reply to this automatically generated notification from Issue Tracker. Please log onto the website and enter your comments. http://qa.openoffice.org/issue_handling/project_issues.html#notification --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
