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For a given score-label-distribution the required precision might not be achievable, in this case 0.0 is returned as recall.

This metric creates four local variables, true_positives, true_negatives, false_positives and false_negatives that are used to compute the recall at the given precision. The threshold for the given precision value is computed and used to evaluate the corresponding recall.

If sample_weight is NULL, weights default to 1. Use sample_weight of 0 to mask values.

If class_id is specified, we calculate precision by considering only the entries in the batch for which class_id is above the threshold predictions, and computing the fraction of them for which class_id is indeed a correct label.

Usage

metric_recall_at_precision(
  ...,
  precision,
  num_thresholds = 200L,
  class_id = NULL,
  name = NULL,
  dtype = NULL
)

Arguments

...

For forward/backward compatability.

precision

A scalar value in range [0, 1].

num_thresholds

(Optional) Defaults to 200. The number of thresholds to use for matching the given precision.

class_id

(Optional) Integer class ID for which we want binary metrics. This must be in the half-open interval [0, num_classes), where num_classes is the last dimension of predictions.

name

(Optional) string name of the metric instance.

dtype

(Optional) data type of the metric result.

Value

a Metric instance is returned. The Metric instance can be passed directly to compile(metrics = ), or used as a standalone object. See ?Metric for example usage.

Usage

Standalone usage:

m <- metric_recall_at_precision(precision = 0.8)
m$update_state(c(0,   0,   1,   1),
               c(0, 0.5, 0.3, 0.9))
m$result()

## tf.Tensor(0.5, shape=(), dtype=float32)

m$reset_state()
m$update_state(c(0,   0,   1,   1),
               c(0, 0.5, 0.3, 0.9),
               sample_weight = c(1, 0, 0, 1))
m$result()

## tf.Tensor(1.0, shape=(), dtype=float32)

Usage with compile() API:

model |> compile(
  optimizer = 'sgd',
  loss = 'binary_crossentropy',
  metrics = list(metric_recall_at_precision(precision = 0.8))
)