https://bugzilla.wikimedia.org/show_bug.cgi?id=235
tahrey <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #35 from tahrey <[email protected]> 2011-03-24 15:12:52 UTC --- Guys ... the feature is a good idea, but I've hit upon an issue with it, and I think it's one that can only have been caused by manual tampering, as a properly written algorithm to deal with the situation I'm about to describe, even I could program, reliably, in about 5 lines of BASIC (bite me if you must - I don't know any other languages). Essentially, it's autoconverting 70 MPH to 110 km/h. Which is both wrong, and inexplicable. It's off by almost 3 km/h (or, almost 2 mph), or about 2.5% - NOT good for an encyclopaedic converter. It's not an instance of anything that's a multiple of 10 (or 5) in the source units being similarly rounded in the output, because 50, 60, 75, 80 work fine (80, 97, 121, 129 km/h). And it's not the converter being just generally "off" by a certain amount, or using the wrong conversion factor, or even being locally skewed. It must have been manually poked to output that MPH as that km/h, unless something very wierd is going on. To test it I threw this code into the sandbox: {{convert|67|mph|abbr=on}} {{convert|68|mph|abbr=on}} {{convert|69|mph|abbr=on}} {{convert|69.9|mph|abbr=on}} {{convert|70|mph|abbr=on}} {{convert|70.1|mph|abbr=on}} {{convert|71|mph|abbr=on}} {{convert|72|mph|abbr=on}} {{convert|73|mph|abbr=on}} ...and this is what I got back. 67 mph (108 km/h) 68 mph (109 km/h) 69 mph (111 km/h) 69.9 mph (112.5 km/h) 70 mph (110 km/h) 70.1 mph (112.8 km/h) 71 mph (114 km/h) 72 mph (116 km/h) 73 mph (117 km/h) Yes, 70mph is less in km/h than both 69 and 69.9mph. And 70.1mph is 2.8km/h higher; 71mph is 4km/h higher. Pretty impressive when there's usually only a 1.6093 ratio between the two units. I don't know if it happens with any other speed, or any other units conversion, but if this one has been distorted, who knows how many others may also be? Please, look into this ASAP. First of all I'm getting tired of manually changing all the misconverted 70s (and can't possibly FIND them all anyway - I picked up on it through a discussion about speed limits, but it's a figure that could easily figure in a lot of other areas ... say, flight speed of a bird or whatever), and secondly it indicates non mathematical tampering in the tool itself that could extend to a lot of other areas. Yeah, 113 km/h isn't a "neat" or "tidy" figure, but none of the others are either. Unit conversions often aren't. The goal of programming one shouldn't be even to DO that, but to return truthful output. You wouldn't accept a calculator that gave you prettified results but then you found it meant your woodwork project didn't match up, would you? If this is an inappropriate place to put this report - i.e. if it would be better as an all new, seperate bug report - please either move it for me, or email me and I'll do it myself. Thanks, T -- Configure bugmail: https://bugzilla.wikimedia.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. You are on the CC list for the bug. _______________________________________________ Wikibugs-l mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/wikibugs-l
