**Umsebenzi we-sigmoid** uwumqondo wezibalo onokusetshenziswa okubanzi emikhakheni efana nokufunda komshini, ukufunda okujulile, nesayensi yedatha, ngenxa yezici zayo ezihlukile zokwenza okukhiphayo kube okujwayelekile phakathi kwebanga elingu-0-1. Umsebenzi we-sigmoid ubalulekile ikakhulukazi ekuhlehleni kwezinto kanye namanethiwekhi okwenziwa kwemizwa, lapho usiza ukunikeza okungenzeka, usize izibikezelo ezinembe kakhulu.
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Ukuxazulula Inkinga Ngomsebenzi we-Sigmoid
Ukuqonda amandla okuxazulula izinkinga omsebenzi we-sigmoid kudinga ukuqonda okucacile kwejika layo eliyingqayizivele, elibonisa umumo 'S'. Leli jika laziwa ngokuthi ijika le-sigmoid futhi lingakwazi ukubala ngempumelelo okokufaka kwenombolo yangempela kububanzi obuphakathi kuka-0 no-1. Lesi sici siyenza ibe ithuluzi eliwusizo ekubaleni okungenzeka. Kanjalo, lesi sici esiyingqayizivele sivumela umsebenzi we-sigmoid ukuthi uchaze kabusha izinkinga, ikakhulukazi lapho okuphumayo kungase kuguquke kakhulu, ngokukukhawulela kububanzi buka-0 no-1.
function sigmoid($t){ return 1/(1+exp(-$t)); }
Umsebenzi we-PHP ongenhla ubonisa ukuqaliswa komsebenzi we-sigmoid. Umsebenzi `exp()` ku-PHP ubuyisela inombolo ka-Euler ephakanyiswe emandleni okokufaka. Lapha, inani lokufakwayo alinakwa (`-t`) ukuze kuqinisekiswe ukuhlelwa okufanele kwedatha. Umphumela wokugcina ube usujwayeleke ngokungeza u-1 kuwo.
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Ukuchaza Ikhodi: Isinyathelo ngesinyathelo
Ikhodi yokusebenza ye-sigmoid ku-PHP iqondile:
function sigmoid($x){ return 1/(1+exp(-$x)); }
Uma ubiza lo msebenzi, dlulisa okokufaka okufunayo njengepharamitha yomsebenzi we-sigmoid. Ukusetshenziswa kokuthi `exp(-$x)` kubala ukumelwa kwe-exponential yenani lokokufaka elingavunyelwe. Umphumela ube usufingqwa ngokuthi 1, `(1+exp(-$x))`, okuhlinzeka idinominetha yengxenye. Ekugcineni, isinyathelo sokugcina, `1/(1+exp(-$x))`, sinikeza okukhiphayo komsebenzi we-sigmoid.
Kuyathakazelisa ukuqaphela ukuthi okokufaka kungaba inoma iyiphi inombolo yangempela, futhi okukhiphayo kuzohlala kukhawulela phakathi kuka-0 no-1 โ isici esenza umsebenzi we-sigmoid ube ukukhetha okuvamile ekubalweni kwamathuba kanye namamodeli okuhlehla kwempahla.
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Imisebenzi kanye Nokuzibandakanya Kwemitapo yolwazi
Ngokuyinhloko, umsebenzi owakhelwe ngaphakathi we-PHP `exp()` usetshenziswa kukhodi engenhla. Lo msebenzi uyingxenye ye-**PHP Math library**, okuhloswe ngayo ukwenza imisebenzi yezibalo.
- Imisebenzi yezibalo ze-PHP: I-PHP inikeza uchungechunge olubanzi lwemisebenzi yezibalo. Ayidingi ukufakwa, futhi singayisebenzisa ngokuqondile. Ekhodini enikeziwe, umsebenzi `exp()` uvela kulo mtapo.
Ukuqonda umsebenzi we-sigmoid nokusebenzisa kwayo ku-PHP kungaba nezithelo ezinhlelweni eziningi zokusebenza, ikakhulukazi lapho uphatha imisebenzi ehlobene nokufunda komshini noma ukuhlukaniswa kwedatha. Ikhono layo eliyingqayizivele lokuchaza kabusha okuphumayo phakathi kwebanga elijwayelekile yilona eliqhuba ukusetshenziswa kwayo okubanzi ezizindeni ezihlukahlukene.