<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">I'd really dislike any solution that makes Swift programming worse than where it currently is. </div><div class=""><br class=""></div><div class="">-- E</div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On Feb 27, 2016, at 6:28 PM, Howard Lovatt <<a href="mailto:howard.lovatt@gmail.com" class="">howard.lovatt@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">I think you have raised a valid concern. But would suggest a simpler solution, remove stride for floating point. You can always write:</span><div style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br class=""></div><div style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">100.stride(through: 200, by 25).map { $0 / 100.0 }<br class=""><br class="">On Sunday, 28 February 2016, Erica Sadun via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;"><div style="word-wrap: break-word;" class=""><div class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word;" class=""><div class="">As implemented, `stride` is broken for floating-point numbers. Instead of repeatedly adding the `by` interval, it should multiply the interval by successive integral values and add that to the base to avoid accruing error. Your proposal only papers over the problem.</div><div class=""><br class=""></div><div class="">-Joe</div></div></div></blockquote></div><br class=""><div class="">Agreed. This is "papering over the problem" of accumulated floating point error. There are two issues being addressed:</div><div class=""><br class=""></div><div class="">1. Semantics of `through` do not match their promise of going through the end point rather than stopping at it or before.</div><div class="">2. Floating point strides accumulate errors by repeatedly adding the `by` interval.</div><div class=""><br class=""></div><div class="">I mention issue 2 in the alternative implementations: <a href="https://gist.github.com/erica/03c398c06f6c47824429" target="_blank" class="">https://gist.github.com/erica/03c398c06f6c47824429</a></div><div class=""><br class=""></div><div class=""><ul style="padding: 0px 0px 0px 2em; margin-top: 0px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255); margin-bottom: 0px !important;" class=""><li class="">Counting expected iterations by forming <code style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">(max - min) / by</code>, e.g. <code style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">(2.0 - 1.0) / 0.1</code>, which is 10, and performing each step as a pro-rated progression along those steps, which would remove most of the accumulated floating point errors along the way.</li></ul><div class=""><br class=""></div><div class="">If you were addressing issue 2, what approach would you suggest:</div></div><div class=""><br class=""></div><div class="">* Differentiating integer strides from floating point, and minimizing floating point errors?</div><div class="">* Leaving the tech as-is with minimal code change with a relatively high benefit?</div><div class=""><br class=""></div><div class="">In both cases, I'd still prefer the semantics to *go through* the end point, not just stop at it, which is issue 1.</div><div class=""><br class=""></div><div class="">-- E</div><div class=""><br class=""></div></div></blockquote></div><br style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">--<span class="Apple-converted-space"> </span></span><br style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Palatino-Roman; font-size: 14px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">-- Howard.</span></div></blockquote></div><br class=""></body></html>