recursionDown uses the function updateDown to compute
daughters rows of matrix param.
recursionDown(phy, params, updateDown, ...)Matrix of parameters updated.
Input tree, in cladewise order.
Matrix of parameters to update by the recursion
Function to be used for the update
Arguments to be used by the function updateDown
This function is to be used in other more complex function that need to update a quantity from the root to the tips of a tree. Note that the input tree must be in cladewise order.