Ask for clarification on comments in the aggregate function

[giuseppefutia]

First of all, thank you for this wonderful resource. Could you please clarify the following part of the comment in the aggregate function?

inputs: (e, d) - messages `m_ij` from destination to source nodes

If I understood the logic, I would expect that the defined messages would go from sources (j nodes) to destination (i nodes). Could you elaborate more this point?

Here is the code of the aggregate function:

def aggregate(self, inputs, index):
        """Step (2) Aggregate

        The `aggregate` function aggregates the messages from neighboring nodes,
        according to the chosen aggregation function ('sum' by default).

        Args:
            inputs: (e, d) - messages `m_ij` from destination to source nodes
            index: (e, 1) - list of source nodes for each edge/message in `input`

        Returns:
            aggr_out: (n, d) - aggregated messages `m_i`
        """
        return scatter(inputs, index, dim=self.node_dim, reduce=self.aggr)

Thank you!