message: Replace text explanation with pseudo equation
diff: @@ -770,10 +770,10 @@ class CategoricalAccuracy(MeanMetricWrapper):
  class SparseCategoricalAccuracy(MeanMetricWrapper):
  """Calculates how often predictions matches integer labels.
  - For example, if `y_true` is `[[2], [1]]` and `y_pred` is
  - `[[0.1, 0.6, 0.3], [0.05, 0.95, 0]]` then the categorical accuracy is 1/2 or .5.
  - If the weights were specified as `[0.7, 0.3]` then the categorical accuracy
  - would be .3. You can provide logits of classes as `y_pred`, since argmax of
  + `acc = dot(sample_weight, (y_true == argmax(y_pred)) / n_pred`
  + where `n_pred = len(y_true)`
  +
  + You can provide logits of classes as `y_pred`, since argmax of
  logits and probabilities are same.
  This metric creates two local variables, `total` and `count` that are used to
  