<SYSTEM_TASK:>
Given the following text description, write Python code to implement the functionality described below step by step
<END_TASK>
<USER_TASK:>
Description:
 Multi-label classification
Step1:  Multi-label versus single-label classification
Step2:  In single-label classification each sample belongs to one class. In the previous example, each image is either a dog or a cat.
Step3:  In multi-label classification each sample can belong to one or more clases. In the previous example, the first images belongs to two clases
Step4:  We use a different set of data augmentations for this dataset - we also allow vertical flips, since we don't expect vertical orientation of satellite images to change our classifications.
<ASSISTANT_TASK:>
Python Code:
%reload_ext autoreload
%autoreload 2
%matplotlib inline
from fastai.conv_learner import *
PATH = 'data/planet/'
# Data preparation steps if you are using Crestle:
os.makedirs('data/planet/models', exist_ok=True)
os.makedirs('/cache/planet/tmp', exist_ok=True)
!ln -s /datasets/kaggle/planet-understanding-the-amazon-from-space/train-jpg {PATH}
!ln -s /datasets/kaggle/planet-understanding-the-amazon-from-space/test-jpg {PATH}
!ln -s /datasets/kaggle/planet-understanding-the-amazon-from-space/train_v2.csv {PATH}
!ln -s /cache/planet/tmp {PATH}
ls {PATH}
Explanation: Multi-label classification
End of explanation
from fastai.plots import *
def get_1st(path): return glob(f'{path}/*.*')[0]
dc_path = "data/dogscats/valid/"
list_paths = [get_1st(f"{dc_path}cats"), get_1st(f"{dc_path}dogs")]
plots_from_files(list_paths, titles=["cat", "dog"], maintitle="Single-label classification")
Explanation: Multi-label versus single-label classification
End of explanation
list_paths = [f"{PATH}train-jpg/train_0.jpg", f"{PATH}train-jpg/train_1.jpg"]
titles=["haze primary", "agriculture clear primary water"]
plots_from_files(list_paths, titles=titles, maintitle="Multi-label classification")
Explanation: In single-label classification each sample belongs to one class. In the previous example, each image is either a dog or a cat.
End of explanation
from planet import f2
metrics=[f2]
f_model = resnet34
label_csv = f'{PATH}train_v2.csv'
n = len(list(open(label_csv)))-1
val_idxs = get_cv_idxs(n)
Explanation: In multi-label classification each sample can belong to one or more clases. In the previous example, the first images belongs to two clases: haze and primary. The second image belongs to four clases: agriculture, clear, primary and  water.
Multi-label models for Planet dataset
End of explanation
def get_data(sz):
    tfms = tfms_from_model(f_model, sz, aug_tfms=transforms_top_down, max_zoom=1.05)
    return ImageClassifierData.from_csv(PATH, 'train-jpg', label_csv, tfms=tfms,
                    suffix='.jpg', val_idxs=val_idxs, test_name='test-jpg')
data = get_data(256)
x,y = next(iter(data.val_dl))
y
list(zip(data.classes, y[0]))
plt.imshow(data.val_ds.denorm(to_np(x))[0]*1.4);
sz=64
data = get_data(sz)
data = data.resize(int(sz*1.3), 'tmp')
learn = ConvLearner.pretrained(f_model, data, metrics=metrics)
lrf=learn.lr_find()
learn.sched.plot()
lr = 0.2
learn.fit(lr, 3, cycle_len=1, cycle_mult=2)
lrs = np.array([lr/9,lr/3,lr])
learn.unfreeze()
learn.fit(lrs, 3, cycle_len=1, cycle_mult=2)
learn.save(f'{sz}')
learn.sched.plot_loss()
sz=128
learn.set_data(get_data(sz))
learn.freeze()
learn.fit(lr, 3, cycle_len=1, cycle_mult=2)
learn.unfreeze()
learn.fit(lrs, 3, cycle_len=1, cycle_mult=2)
learn.save(f'{sz}')
sz=256
learn.set_data(get_data(sz))
learn.freeze()
learn.fit(lr, 3, cycle_len=1, cycle_mult=2)
learn.unfreeze()
learn.fit(lrs, 3, cycle_len=1, cycle_mult=2)
learn.save(f'{sz}')
multi_preds, y = learn.TTA()
preds = np.mean(multi_preds, 0)
f2(preds,y)
Explanation: We use a different set of data augmentations for this dataset - we also allow vertical flips, since we don't expect vertical orientation of satellite images to change our classifications.
End of explanation
<END_TASK>