https://svn.boost.org/trac10/ticket/11335 <p> See attached patch. </p> <p> The conversion factor used by the existing code only used three decimal places. However, the standardised conversion factor is 9 decimal places, and is also used in GNU units. Changing to use the full 133.322387415 significantly improves accuracy. </p> <p> I can't put a link in the report since it makes the ticket get rejected as spam, but see the first paragraph of the "Millimeter of mercury" wikepedia page, and GNU units for reference. </p> <p> Defect is in the latest boost back to at least 1.55. </p> <p> Please consider applying the attached patch. </p> <p> Thanks, Roger </p> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/11335 Trac 1.4.3 Roger Leigh <rleigh@…> Fri, 22 May 2015 20:14:16 GMT https://svn.boost.org/trac10/ticket/11335 https://svn.boost.org/trac10/ticket/11335 <ul> <li><strong>attachment</strong> → <span class="trac-field-new">0001-base_units-mmHg-Improve-precision-for-Pascal-convers.patch</span> </li> </ul> <p> Patch to improve accuracy of mmHg to Pascal conversion </p> Ticket