Revision history [back]

vektor field in ploes go wild with the arrows near the poles - how to fix?

 x,y = var('x y')

f=1/sqrt(x^2+y^2)


gives me this

As you can see the errors very close to the pole "cross out" the whole pic. Obviously they are very large vectors, but they do harm the overall image. i have other plots where its worse. How can i work around that? can i blank out the direkt proximity of the pole, somehow? can i limit the vektors' length? How?

vektor field in ploes go wild with the arrows near the poles - how to fix?

 x,y = var('x y')
y')  f=1/sqrt(x^2+y^2)
gives me this  As you can see the errors arrows very close to the pole "cross out" the whole pic. Obviously they are very large vectors, but they do harm the overall image. i I have other plots where its worse. How can i I work around that? can i Can I blank out the direkt proximity of the pole, somehow? can i Can I limit the vektors' length? How? 


 3 None updated 2019-04-13 11:14:00 +0200 vektor field in ploes go wild with the arrows near the poles - how to fix? x,y = var('x y') f=1/sqrt(x^2+y^2) grad= f.gradient([x,y]) plot_vector_field(grad, (x,-1,1), (y,-1,1)).show() gives me this As you can see the arrows very close to the pole "cross out" the whole pic. Obviously they are very large vectors, but they do harm the overall image. I have other plots where its worse. How can I work around that? Can I blank out the direkt proximity of the pole, somehow? Can I limit the vektors' length? How? 4 None updated 2019-04-13 12:53:16 +0200 slelievre 14559 ●16 ●136 ●287 http://carva.org/samue... vektor field in ploes poles go wild with the arrows near the poles - how to fix? x,y = var('x y') f=1/sqrt(x^2+y^2) grad= f.gradient([x,y]) plot_vector_field(grad, (x,-1,1), (y,-1,1)).show() gives me this As you can see the arrows very close to the pole "cross out" the whole pic. Obviously they are very large vectors, but they do harm the overall image. I have other plots where its worse. How can I work around that? Can I blank out the direkt proximity of the pole, somehow? Can I limit the vektors' length? How? 5 None updated 2019-04-13 23:56:55 +0200 slelievre 14559 ●16 ●136 ●287 http://carva.org/samue... vektor Arrow length goes wild near poles in vector field in poles go wild with the arrows near the poles - how to fix?plot x,y = var('x y')Running this piece of code f=1/sqrt(x^2+y^2) grad= f.gradient([x,y]) x, y = var('x y') f = 1/sqrt(x^2 + y^2) grad = f.gradient([x, y]) plot_vector_field(grad, (x,-1,1), (y,-1,1)).show() (x, -1, 1), (y, -1, 1)).show() gives me this As you can see the arrows very close to the pole "cross out" the whole pic. Obviously they are very large vectors, but they do harm the overall image. I have other plots where its worse. How can I work around that? Can I blank out the direkt direct proximity of the pole, somehow? Can I limit the vektors' vectors' length? How? 


 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license. about | faq | help | privacy policy | terms of service Powered by Askbot version 0.7.59 Please note: Askbot requires javascript to work properly, please enable javascript in your browser, here is how //IE fix to hide the red margin var noscript = document.getElementsByTagName('noscript')[0]; noscript.style.padding = '0px'; noscript.style.backgroundColor = 'transparent'; askbot['urls']['mark_read_message'] = '/s/messages/markread/'; askbot['urls']['get_tags_by_wildcard'] = '/s/get-tags-by-wildcard/'; askbot['urls']['get_tag_list'] = '/s/get-tag-list/'; askbot['urls']['follow_user'] = '/followit/follow/user/{{userId}}/'; askbot['urls']['unfollow_user'] = '/followit/unfollow/user/{{userId}}/'; askbot['urls']['user_signin'] = '/account/signin/'; askbot['urls']['getEditor'] = '/s/get-editor/'; askbot['urls']['apiGetQuestions'] = '/s/api/get_questions/'; askbot['urls']['ask'] = '/questions/ask/'; askbot['urls']['questions'] = '/questions/'; askbot['settings']['groupsEnabled'] = false; askbot['settings']['static_url'] = '/m/'; askbot['settings']['minSearchWordLength'] = 4; askbot['settings']['mathjaxEnabled'] = true; askbot['settings']['sharingSuffixText'] = ''; askbot['settings']['errorPlacement'] = 'after-label'; askbot['data']['maxCommentLength'] = 800; askbot['settings']['editorType'] = 'markdown'; askbot['settings']['commentsEditorType'] = 'rich\u002Dtext'; askbot['messages']['askYourQuestion'] = 'Ask Your Question'; askbot['messages']['acceptOwnAnswer'] = 'accept or unaccept your own answer'; askbot['messages']['followQuestions'] = 'follow questions'; askbot['settings']['allowedUploadFileTypes'] = [ "jpg", "jpeg", "gif", "bmp", "png", "tiff" ]; askbot['data']['haveFlashNotifications'] = true; askbot['data']['activeTab'] = 'questions'; askbot['settings']['csrfCookieName'] = 'asksage_csrf'; askbot['data']['searchUrl'] = ''; /*<![CDATA[*/ $('.mceStatusbar').remove();//a hack to remove the tinyMCE status bar$(document).ready(function(){ // focus input on the search bar endcomment var activeTab = askbot['data']['activeTab']; if (inArray(activeTab, ['users', 'questions', 'tags', 'badges'])) { var searchInput = $('#keywords'); } else if (activeTab === 'ask') { var searchInput =$('#id_title'); } else { var searchInput = undefined; animateHashes(); } var wasScrolled = $('#scroll-mem').val(); if (searchInput && !wasScrolled) { searchInput.focus(); putCursorAtEnd(searchInput); } var haveFullTextSearchTab = inArray(activeTab, ['questions', 'badges', 'ask']); var haveUserProfilePage =$('body').hasClass('user-profile-page'); if ((haveUserProfilePage || haveFullTextSearchTab) && searchInput && searchInput.length) { var search = new FullTextSearch(); askbot['controllers'] = askbot['controllers'] || {}; askbot['controllers']['fullTextSearch'] = search; search.setSearchUrl(askbot['data']['searchUrl']); if (activeTab === 'ask') { search.setAskButtonEnabled(false); } search.decorate(searchInput); } else if (activeTab === 'tags') { var search = new TagSearch(); search.decorate(searchInput); } if (askbot['data']['userIsAdminOrMod']) { $('body').addClass('admin'); } if (askbot['settings']['groupsEnabled']) { askbot['urls']['add_group'] = "/s/add-group/"; var group_dropdown = new GroupDropdown();$('.groups-dropdown').append(group_dropdown.getElement()); } var userRep = $('#userToolsNav .reputation'); if (userRep.length) { var showPermsTrigger = new ShowPermsTrigger(); showPermsTrigger.decorate(userRep); } }); if (askbot['data']['haveFlashNotifications']) {$('#validate_email_alert').click(function(){notify.close(true)}) notify.show(); } var langNav = $('.lang-nav'); if (langNav.length) { var nav = new LangNav(); nav.decorate(langNav); } /*]]>*/ if (typeof MathJax != 'undefined') { MathJax.Hub.Config({ extensions: ["tex2jax.js"], jax: ["input/TeX","output/HTML-CSS"], tex2jax: {inlineMath: [["$","$"],["\$","\$"]]} }); } else { console.log('Could not load MathJax'); } //todo - take this out into .js file$(document).ready(function(){ $('div.revision div[id^=rev-header-]').bind('click', function(){ var revId = this.id.substr(11); toggleRev(revId); }); lanai.highlightSyntax(); }); function toggleRev(id) { var arrow =$("#rev-arrow-" + id); var visible = arrow.attr("src").indexOf("hide") > -1; if (visible) { var image_path = '/m/default/media/images/expander-arrow-show.gif?v=19'; } else { var image_path = '/m/default/media/images/expander-arrow-hide.gif?v=19'; } image_path = image_path + "?v=19"; arrow.attr("src", image_path); \$("#rev-body-" + id).slideToggle("fast"); } for (url_name in askbot['urls']){ askbot['urls'][url_name] = cleanUrl(askbot['urls'][url_name]); }