def build(self, predictions, targets, inputs):
        self.built = True
        self.tensor = r2_op(predictions, targets, inputs)
        # Add a special name to that tensor, to be used by monitors
        self.tensor.m_name = self.name


# ----------
# Metric ops
# ----------
Build standard error tensor.
dataset/ETHPy150Open tflearn/tflearn/tflearn/metrics.py/R2.build