1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
# TensorFlow evaluation metrics and summary statistics
## Evaluation metrics
Metrics are used in evaluation to assess the quality of a model. Most are
"streaming" ops, meaning they create variables to accumulate a running total,
and return an update tensor to update these variables, and a value tensor to
read the accumulated value. Example:
value, update_op = metrics.streaming_mean_squared_error(
predictions, targets, weight)
Most metric functions take a pair of tensors, `predictions` and ground truth
`targets` (`streaming_mean` is an exception, it takes a single value tensor,
usually a loss). It is assumed that the shape of both these tensors is of the
form `[batch_size, d1, ... dN]` where `batch_size` is the number of samples in
the batch and `d1` ... `dN` are the remaining dimensions.
The `weight` parameter can be used to adjust the relative weight of samples
within the batch. The result of each loss is a scalar average of all sample
losses with non-zero weights.
The result is 2 tensors that should be used like the following for each eval
run:
```python
predictions = ...
labels = ...
value, update_op = some_metric(predictions, labels)
for step_num in range(max_steps):
update_op.run()
print "evaluation score: ", value.eval()
```
|
