tf.summary.scalar

Write a scalar summary.

name A name for this summary. The summary tag used for TensorBoard will be this name prefixed by any active name scopes.
data A real numeric scalar value, convertible to a float32 Tensor.
step Explicit int64-castable monotonic step value for this summary. If omitted, this defaults to tf.summary.experimental.get_step(), which must not be None.
description Optional long-form description for this summary, as a constant str. Markdown is supported. Defaults to empty.

True on success, or false if no summary was written because no default summary writer was available.

ValueError if a default writer exists, but no step was provided and tf.summary.experimental.get_step() is None.