Αποτελέσματα Αναζήτησης
Python does not have built-in support for trees, I have supplied a module for use in the course. This document provides background on the types of trees supported by the module as well as speci cs of the methods and functions provided.
A tree T is a set of nodes storing elements such that the nodes have a parent-child relationship that satisfies the following properties: • If T is nonempty, it has a special node, called the root of T ,
current_tree.set_root_val(i) current_tree.insert_right('') p_stack.push(current_tree) current_tree = current_tree.get_right_child() elif i == ")": current_tree = p_stack.pop() else: raise ValueError("invalid expression given!") return e_tree pt = buildParseTree("( ( 10 + 5 ) * 3 )")
These three exercises cover three very common ROOT usage scenarios: 1. Processing data from a TTree, lling a histogram, and writing the results to an output. 2. Reading a. 3. Reading a le that contains a histogram and tting the histogram in di erent ways, writing the results to a pdf.
Like the other data structures we've discussed, trees are mutable- they can be changed. But we don't have built-in methods to make these changes, so we have to modify the structure ourselves. First, updating a value in the tree is easy; just find the node you want to change and update t["value"] for that node.
Any node within a tree can be viewed as a root of its own subtree - just take any node, cut of the branch/edge that connects above to the rest of a tree, and it becomes a root with a smaller (possibly empty) tree of its own.
Toytree includes functions to generate random trees in the .rtree submodule, and to modify trees in the .mod submodule. The .rtree functions can generate trees that are balanced or imbalanced, with equal or random branch lengths, and as coalescent trees. The .mod functions can be used to scale node heights by a constant, to ran‐
