{"id":4671,"date":"2016-01-22T23:20:49","date_gmt":"2016-01-22T15:20:49","guid":{"rendered":"https:\/\/lttt.vanabel.info\/?p=4671"},"modified":"2016-01-22T23:20:49","modified_gmt":"2016-01-22T15:20:49","slug":"ruhehuaquiver","status":"publish","type":"post","link":"https:\/\/lttt.vanabel.cn\/?p=4671","title":{"rendered":"\u5982\u4f55\u753b Quiver"},"content":{"rendered":"<p><img decoding=\"async\" src=\"\/\/lttt.blog.ustc.edu.cn\/wp-content\/uploads\/2016\/01\/quiver.png\" alt=\"Quiver Example\" \/><br \/>\n<!--more--><\/p>\n<pre class=\"lang:default decode:true \" >\\documentclass{amsart}\n\\usepackage{mpgraphics}\n\\begin{mpdefs}\nu=10pt;\nvardef pst(expr labdr)=\n begingroup\n  os:=.7u;\n  pair odr;\n  if (labdr=\"u\") :  odr:=os*up; fi;\n  if (labdr=\"d\") :  odr:=os*down; fi;\n  if (labdr=\"l\") :  odr:=os*left; fi;\n  if (labdr=\"r\") :  odr:=os*right; fi;\n endgroup;\n odr\nenddef;\n\nvardef quiver(expr P, Q, labP, labQ, labPQ, pstP, pstQ) =\n begingroup\n  os:=0.3u;\n  pair dr;\n  dr:=unitvector(Q-P);\n\n  pickup pencircle scaled 1pt;\n  drawarrow P+os*dr--Q-os*dr;\n\n  pickup pencircle scaled 1pt;\n  label(btex $\\circ$ etex, P);\n  label(labP, pst(pstP)+P);\n  label(btex $\\circ$ etex,Q);\n  label(labQ, pst(pstQ)+ Q);\n  label (labPQ, os*(dr rotated 90)+(P+Q)\/2);\n endgroup;\nenddef;\n\\end{mpdefs}\n\\begin{document}\n  this is a test \\begin{mpdisplay}\n    z1=origin;\n    z2=3u*(down+right);\n    z3=z2+3u*(left+down);\n    z4=z3+6u*(up+left);\n    quiver(z1,z2,\"1\",\"2\", btex $\\alpha_1$ etex, \"u\", \"r\");\n    quiver(z2,z3,\"2\",\"3\", btex $\\alpha_2$ etex, \"r\", \"d\");\n    quiver(z3,z4,\"3\",\"4\", btex $\\alpha_3$ etex, \"d\", \"l\");\n    quiver(z4,z1,\"4\",\"1\", btex $\\alpha_4$ etex, \"l\", \"u\");\n  \\end{mpdisplay} \n  and this is not right\n\\end{document}<\/pre>\n<p>This is just a basic idea, after a while, I find the following complete package <a href=\"http:\/\/vigna.di.unimi.it\/metagraph\/\">METAGRAPH<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[555,599],"class_list":["post-4671","post","type-post","status-publish","format-standard","hentry","category-latex","tag-metapost","tag-quiver"],"_links":{"self":[{"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=\/wp\/v2\/posts\/4671","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4671"}],"version-history":[{"count":0,"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=\/wp\/v2\/posts\/4671\/revisions"}],"wp:attachment":[{"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4671"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4671"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lttt.vanabel.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4671"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}