{"id":3757,"date":"2018-02-20T06:00:06","date_gmt":"2018-02-20T04:00:06","guid":{"rendered":"http:\/\/www.glc.us.es\/~jalonso\/exercitium\/?p=3757"},"modified":"2018-02-27T07:29:24","modified_gmt":"2018-02-27T05:29:24","slug":"representacion-reducida-de-matrices-dispersas","status":"publish","type":"post","link":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/representacion-reducida-de-matrices-dispersas\/","title":{"rendered":"Representaci\u00f3n reducida de matrices dispersas"},"content":{"rendered":"<p>Una representaci\u00f3n reducida de una matriz dispersa es una lista de listas donde cada una de las listas representa una fila de la matriz mediante listas de pares correspondientes a las sn\u00fameros de columnas con valores no nulos de la matriz. Por ejemplo, la representacio\u0144 reducida de la matriz<\/p>\n<pre lang=\"text\">\n   ( 0 0 4 )\n   ( 0 5 0 )\n   ( 0 0 0 )\n<\/pre>\n<p>es [[(3,4)],[(2,5)],[]].<\/p>\n<p>Definir la funci\u00f3n<\/p>\n<pre lang=\"text\">\n   reducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]]\n<\/pre>\n<p>tal que (reducida p) es la representaci\u00f3n reducida de la matriz p. Por ejemplo,<\/p>\n<pre lang=\"text\">\n   reducida (fromList 3 3 [0,0,4,0,5,0,0,0,0])  ==  [[(3,4)],[(2,5)],[]]\n   reducida (identity 3)  ==  [[(1,1)],[(2,1)],[(3,1)]]\n   reducida (zero 9 3)    ==  [[],[],[],[],[],[],[],[],[]]\n   reducida (zero 9 4)    ==  [[],[],[],[],[],[],[],[],[]]\n<\/pre>\n<h4>Soluciones<\/h4>\n<pre lang=\"haskell\">\nimport Data.Matrix (Matrix, (!), nrows, ncols)\n\nreducida :: (Num a, Eq a) => Matrix a -> [[(Int,a)]]\nreducida p =\n  [[(j,x) | j <- [1..n], let x = p!(i,j), x \/= 0] | i <- [1..m]] \n  where m = nrows p\n        n = ncols p\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Una representaci\u00f3n reducida de una matriz dispersa es una lista de listas donde cada una de las listas representa una fila de la matriz mediante listas de pares correspondientes a las sn\u00fameros de columnas con valores no nulos de la matriz. Por ejemplo, la representacio\u0144 reducida de la matriz ( 0 0 4 ) (&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"footnotes":"","_jetpack_memberships_contains_paid_content":false},"categories":[5],"tags":[8,42,99,98],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/3757"}],"collection":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/comments?post=3757"}],"version-history":[{"count":3,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/3757\/revisions"}],"predecessor-version":[{"id":3825,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/posts\/3757\/revisions\/3825"}],"wp:attachment":[{"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/media?parent=3757"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/categories?post=3757"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.glc.us.es\/~jalonso\/exercitium\/wp-json\/wp\/v2\/tags?post=3757"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}