Akoranga TensorFlow mō ngā Tīmatanga
Ko TensorFlow tētahi o ngā anga ako tino rongonui mō te ako hōhonu me te ako mīhini. Nā te tīma Google Brain i whakawhanake, kua whānuitia te whakamahinga o TensorFlow i roto i ngā kaupapa rangahau me ngā tono ahumahi maha. Kei roto i tēnei tuhinga he akoranga taahiraa-i-te-taahiraa hei āwhina i a koe, hei tīmatanga, ki te tīmata ki a TensorFlow.
1. Te Mārama ki ngā Kaupapa Taketake o TensorFlow
I mua i te tīmatanga o te tāuta me te whakamahi i a TensorFlow, he mea nui kia mārama tātou he aha a TensorFlow me ngā ariā taketake kei muri. He anga tuwhera a TensorFlow mō te tatau tau me te ako mīhini. Ka whakamahia e ia ngā kauwhata rere raraunga hei mahi i ngā mahi tau, ko ngā pona i roto i te kauwhata e tohu ana i ngā mahi pāngarau, ā, ko ngā tapa e tohu ana i ngā huinga raraunga maha-ahu (tensor) e hono ana i waenganui i a rātou.
2. Tāutanga o TensorFlow
Ko te taahiraa tuatahi ki te whakamahi i a TensorFlow ko te tāuta. Anei me pēhea te tāuta i a TensorFlow mā te whakamahi i te pip, te kaiwhakahaere mōkihi Python.
1. Tāutanga Python:
Kia tino tāutahia te Python ki tō pūnaha. Kei te hototahi a TensorFlow ki te Python 3.6 ki te 3.9 i te wā e tuhia ana tēnei. Ka taea e koe te tango i te Python mai i te paetukutuku Python mana.
2. Taiao Mariko:
He tino taunaki kia waihangahia he taiao mariko hei wehe i tō kaupapa TensorFlow:
"sh"
python -m venv myenv
pūtake myenv/bin/activate Mō ngā kaiwhakamahi Mac/Linux
myenv\Scripts\activate Mō ngā kaiwhakamahi Windows
""
3. Tāutanga o TensorFlow:
Inaianei, tāutahia a TensorFlow mā te whakamahi i te pip:
"sh"
te tāuta paipa tensorflow
""
3. Kia ora te ao me te TensorFlow
Nā te mea kua tāutahia a TensorFlow, me waihanga he tuhinga Python māmā hei manatoko i te tāutanga. Waihangahia he kōnae Python hou, ka tapaina ko `hello_tensorflow.py`.
"`Pitoni
kawemai te tensorflow hei tf
Waihangahia he pūmau
kia ora = tf.constant('Kia ora, TensorFlow!')
Tīmatahia te wātū
me tf.Session() hei sess:
hua = sess.run(kia ora)
tā(hua)
""
Whakarerekētia te waehere kia rite ki te putanga 2.x o TensorFlow:
"`Pitoni
kawemai te tensorflow hei tf
Waihangahia he pūmau
kia ora = tf.constant('Kia ora, TensorFlow!')
Whakahaerehia mā te whakamahi i te eager execution (e whakahohea ana mā te taunoa)
tā(kia ora.numpy())
""
Tiakina te kōnae, kātahi ka whakahaere:
"sh"
python hello_tensorflow.py
""
4. Te Mārama ki ngā Tensor me ngā Mahi Taketake
Ko ngā Tensor te hanganga raraunga matua i roto i te TensorFlow, he huinga maha-ahu. Anei ētahi tauira hei āwhina i a koe ki te mārama ki ngā tensor:
"`Pitoni
kawemai te tensorflow hei tf
Te waihanga i ngā tensor
tauine = tf. pūmau(7) tauine
te whārite = tf. pūmau([1, 2, 3]) te whārite
matihiko = tf. matihiko pūmau([[1, 2], [3, 4]])
tensor3d = tf.pūmau([[[1, 2, 3], [4, 5, 6]], [[7, 8, 9], [10, 11, 12]]]) tensor 3D
tā(f'Tauine: {tauine}')
tā(f'Huarahi: {huarahi}')
tā(f'Matrix: {matrix}')
tā(f'Tensor 3D: {tensor3d}')
""
Hei mahi i ngā mahi taketake i runga i ngā tensor:
"`Pitoni
a = tf.pūmau([[1, 2], [3, 4]])
b = tf.pūmau([[5, 6], [7, 8]])
Te mahi tāpiri
tāpiri = tf.tāpiri(a, b)
Ngā mahi whakarea matihiko
mul = tf.matmul(a, b)
tā(f'Tāpiri: {tāpiri}')
tā(f'Whakareatanga Matrix: {mul}')
""
5. Te Waihanga i tētahi Tauira Whatunga Io Māmā
Ko te mahi e whai ake nei ko te waihanga i tētahi tauira whatunga io māmā. Ka hangaia e mātou he tauira whakarōpūtanga whakaahua mā te whakamahi i te huinga raraunga MNIST, he pātengi raraunga o ngā whakaahua mati kua tuhia ā-ringa. Me tīmata tātou:
"`Pitoni
kawemai te tensorflow hei tf
mai i tensorflow.keras kawemai i ngā huinga raraunga, ngā paparanga, ngā tauira
Te tango i te huinga raraunga MNIST
(whakaahua_tereina, tapanga_tereina), (whakaahua_whakamātautau, tapanga_whakamātautau) = huinga raraunga.mnist.uta_raraunga()
Whakaōritenga ahua
whakaahua_tereina, whakaahua_whakamātautau = whakaahua_tereina / 255.0, whakaahua_whakamātautau / 255.0
Te hanga tauira
tauira = tauira.Raupapa([
ngā paparanga.Whakapapatahi(āhua_whakauru=(28, 28)),
layers.Dense(128, activation='relu'),
ngā paparanga.Kīkī(10)
])
Te whakahiato tauira
tauira.whakahiato(kaiwhakapaipai='atama',
ngaronga=tf.keras.ngaronga.SparseCategoricalCrossentropy(from_logits=Tino),
inenga=['tika'])
Te whakangungu i te tauira
tauira.taurite(whakaahua_tereina, tapanga_tereina, wā=5)
Te whakamātautau i te tauira
ngaromanga_whakamātautau, whakamātautau_acc = tauira.arotake(whakamātautau_whakaahua, tapanga_whakamātautau)
tā(f'Te tika o te whakamātautau: {test_acc}')
""
Whakamārama:
– Huinga Raraunga: Ka kawemai mātou, ka utaina hoki te huinga raraunga MNIST.
– Te Tukatuka-mua: Whakaōritehia te huinga raraunga mā te wehewehe i ngā uara pika mā te 255.
– Tauira: Ka tautuhia e mātou he tauira māmā me ngā paparanga e rua. Ko te paparanga tuatahi he paparanga `Whakapapa` hei huri i te ahua 2D ki te rarangi 1D. Ko te paparanga tuarua he paparanga `Kīkī` me ngā neuron 128 me te `relu` hei mahi whakahohe, ā, ko te mea whakamutunga he paparanga `Kīkī` me ngā neuron 10 e tohu ana i ngā akomanga 10.
– Whakahiato: Ka whakahiatohia e mātou te tauira mā te whakamahi i te `adam` optimizer me te `SparseCategoricalCrossentropy` hei mahi ngaronga.
– Whakangungu: Whakangunguhia te tauira mō ngā wā e 5.
– Aromātai: Aromātaihia te tauira ki ngā raraunga whakamātautau.
6. Te Tiaki me te Utaina o ngā Tauira
I muri i te whakangungu i tētahi tauira, ka hiahia pea koe ki te tiaki mō te whakamahinga ā muri ake nei, me te kore e hiahiatia kia whakangungua anō. Anei me pēhea te tiaki me te uta i tētahi tauira:
"`Pitoni
Te tiaki i te tauira
tauira.tiaki('taku_tauira.h5')
Tauira utaina
tauira_hou = tf.keras.tauira.uta_tauira('taku_tauira.h5′)
Te manatoko i te tauira kua utaina
ngaronga, pūkete = tauira_hou.aromatawai(whakamātautau_whakaahua, tapanga_whakamātautau)
tā(f'Te tika o te tauira kua utaina: {acc}')
""
Whakamutunga
Kei roto i tēnei aratohu he whakataki taipitopito mō te tīmatanga ki a TensorFlow mō ngā tīmatanga. Kua hipokina e mātou te tāutanga, ngā mahi tensor taketake, me te hanga i tētahi tauira whatunga io māmā mā te whakamahi i te huinga raraunga MNIST. He maha ngā āheinga matatau a TensorFlow hei tūhura, pērā i te tukatuka raraunga matatau, ngā tauira uaua ake, me te whakamahi i a TensorFlow i runga i ngā taputapu pēnei i ngā TPU me ngā GPU. Ko te tumanako ka āwhina tēnei akoranga i a koe ki te tīmata i te ao o te ako mīhini me TensorFlow.
