18477 2012-08-02 21:44:18 +0000 [QT3] different results for some atan2 test cases 2012-09-25 20:24:56 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XQuery 3 & XPath 3 Test Suite Last Call drafts PC Windows XP CLOSED INVALID P2 normal --- 1 andrew.eisenberg oneil public-qt-comments oldest_to_newest 71787 0 andrew.eisenberg 2012-08-02 21:44:18 +0000 I am seeing different results for a number of atan2 test cases: - math-atan2-005 math:atan2(-1, -0.0e0) actual: 3.14159265358979 expected: -math:pi() div 2 excel: 3.141592654 - math-atan2-006 math:atan2(+1, 0.0e0) actual: 0 expected: +math:pi() div 2 excel: 0 - math-atan2-007 math:atan2(-0.0e0, -1) actual: -1.5707963267949 expected: -math:pi() excel: -1.570796327 - math-atan2-008 math:atan2(+0.0e0, -1) actual: -1.5707963267949 expected: +math:pi() excel: -1.570796327 - math-atan2-009 math:atan2(-0.0e0, +1) actual: 1.5707963267949 expected: -0.0e0 excel: 1.570796327 - math-atan2-010 math:atan2(+0.0e0, +1) actual: 1.5707963267949 expected: +0.0e0 excel: 1.570796327 74425 1 oneil 2012-09-25 14:17:56 +0000 Please may you check your implementation. Some libraries including excel use atan2(x,y) where as our specification uses atan2(y,x). Does this account for the discrepancies? 74463 2 andrew.eisenberg 2012-09-25 20:24:42 +0000 As you had guessed, the library that I am using defines atan2(x,y). Thanks for pointing this out to me.