March 2019
Intermediate to advanced
256 pages
4h 57m
French
Content preview from Machine learning : les fondamentauxBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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CHAPITRE 8 Sélection de caractéristiques
La sélection de caractéristiques permet de se concentrer sur celles qui sont utiles au modèle. En effet, les caractéristiques non pertinentes peuvent avoir un effet négatif. Par exemple, les caractéristiques corrélées rendent instables ou difficiles à interpréter les coefficients dans les régressions ou l’importance des caractéristiques dans les modèles arborescents.
Il faut également craindre la malédiction des dimensions. En augmentant le nombre de dimensions dans vos données, vous les rendez moins denses, ce qui rend de plus en plus difficile l’extraction de signaux intéressants, sauf à ajouter encore des données. Les calculs de voisinage deviennent de moins en moins fructueux.
Il faut enfin tenir compte ...
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