{"id":407201,"date":"2025-01-27T13:32:25","date_gmt":"2025-01-27T13:32:25","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/why-ansys-mechanical-is-single-precision-only\/"},"modified":"2025-02-19T14:15:28","modified_gmt":"2025-02-19T14:15:28","slug":"why-ansys-mechanical-is-single-precision-only","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/why-ansys-mechanical-is-single-precision-only\/","title":{"rendered":"Why Ansys Mechanical is single precision only?"},"content":{"rendered":"

<p><p>I have a little example with simple beam bending. One side is clamped, on the other side a single node undergoes a z-displacement of 1.23456789 mm:<\/p><p>\"\"<\/p><p>After calculation, the maximum displacement at this node is 1.2345678<span style=”text-decoration: underline;”><span style=”color: #ba372a; text-decoration: underline;”>81<\/span><\/strong><\/span> only. If you read this displacement with Python console inside Mechanical you get also a value of 1.2345678<span style=”text-decoration: underline;”><span style=”color: #ba372a; text-decoration: underline;”>8063<\/span><\/strong><\/span>. This is exactly the value that you get if you store 1.23456789 in a single-precision floating point number (can be tried out with any programming language). This shows me that Ansys Mechanical works internally with single-precision numbers.<\/p><p>\"\"<\/p><p>But the displacement values are stored inside the RST file with double-precision! If you open Ansys Classic an load that RST from the Workbench file structure, the you can get the exact displacement (Classic only):<\/p><\/p><\/p>\n

\/post1<\/strong><br>file,' c:\\scratch\\test\\dp0\\SYS\\MECH\\file',rst<\/strong><br>set,1<\/strong><br>\/format,7,f,16<\/strong><br>prnsol,u,z<\/strong><\/pre>\n
<p><p>And the list you get is:<\/p><\/p><\/p>\n
NODE               UZ<\/strong><br> ...<\/strong><br>121   <span style=\"color: #169179;\">1.234567890000<\/span><\/strong><\/pre>\n
<p><p>Or can I change the behavior of Mechanical to get the exact displacements? We have large numbers with large displacements, so this inaccuracy is a problem for a very specific use case.<\/p><p>Thanks!<\/p><\/p><\/p>\n","protected":false},"template":"","class_list":["post-407201","topic","type-topic","status-closed","hentry","topic-tag-ansys-mechanical","topic-tag-AnsysMechanical2021R2-1","topic-tag-displacement","topic-tag-precision"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27791"],"_bbp_topic_id":["407201"],"_bbp_subscription":["507715","58821"],"_bbp_author_ip":["2a02:810a:8601:9600:8c29:18cc:2c35:b2d3"],"_bbp_last_reply_id":["422372"],"_bbp_last_active_id":["422372"],"_bbp_last_active_time":["2025-02-19 14:15:20"],"_bbp_reply_count":["5"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["507715","58821"],"_btv_view_count":["404"],"_bbp_topic_status":["unanswered"],"_edit_last":["52629"],"_bbp_revision_log":["a:1:{i:407208;a:2:{s:6:\"author\";i:52629;s:6:\"reason\";s:0:\"\";}}"],"_edit_lock":["1737987238:52629"],"_bbp_status":["publish"]},"test":"82dc02165941b2d28fe4a8a42d410c611c438a6f"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/407201","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":1,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/407201\/revisions"}],"predecessor-version":[{"id":407208,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/407201\/revisions\/407208"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=407201"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}