|
| 1 | +import DynamicExpressions: |
| 2 | + Node, copy_node, set_node!, count_nodes, has_constants, has_operators |
| 3 | + |
| 4 | +# This code is copied from SymbolicRegression.jl and modified |
| 5 | + |
| 6 | +# Return a random node from the tree |
| 7 | +function random_node(tree::Node{T})::Node{T} where {T} |
| 8 | + if tree.degree == 0 |
| 9 | + return tree |
| 10 | + end |
| 11 | + b = 0 |
| 12 | + c = 0 |
| 13 | + if tree.degree >= 1 |
| 14 | + b = count_nodes(tree.l) |
| 15 | + end |
| 16 | + if tree.degree == 2 |
| 17 | + c = count_nodes(tree.r) |
| 18 | + end |
| 19 | + |
| 20 | + i = rand(1:(1 + b + c)) |
| 21 | + if i <= b |
| 22 | + return random_node(tree.l) |
| 23 | + elseif i == b + 1 |
| 24 | + return tree |
| 25 | + end |
| 26 | + |
| 27 | + return random_node(tree.r) |
| 28 | +end |
| 29 | + |
| 30 | +function make_random_leaf(nfeatures::Int, ::Type{T})::Node{T} where {T} |
| 31 | + if rand() > 0.5 |
| 32 | + return Node(; val=randn(T)) |
| 33 | + else |
| 34 | + return Node(T; feature=rand(1:nfeatures)) |
| 35 | + end |
| 36 | +end |
| 37 | + |
| 38 | +# Add a random unary/binary operation to the end of a tree |
| 39 | +function append_random_op( |
| 40 | + tree::Node{T}, operators, nfeatures::Int; makeNewBinOp::Union{Bool,Nothing}=nothing |
| 41 | +)::Node{T} where {T} |
| 42 | + nuna = length(operators.unaops) |
| 43 | + nbin = length(operators.binops) |
| 44 | + |
| 45 | + node = random_node(tree) |
| 46 | + while node.degree != 0 |
| 47 | + node = random_node(tree) |
| 48 | + end |
| 49 | + |
| 50 | + if makeNewBinOp === nothing |
| 51 | + choice = rand() |
| 52 | + makeNewBinOp = choice < nbin / (nuna + nbin) |
| 53 | + end |
| 54 | + |
| 55 | + if makeNewBinOp |
| 56 | + newnode = Node( |
| 57 | + rand(1:nbin), make_random_leaf(nfeatures, T), make_random_leaf(nfeatures, T) |
| 58 | + ) |
| 59 | + else |
| 60 | + newnode = Node(rand(1:nuna), make_random_leaf(nfeatures, T)) |
| 61 | + end |
| 62 | + |
| 63 | + set_node!(node, newnode) |
| 64 | + |
| 65 | + return tree |
| 66 | +end |
| 67 | + |
| 68 | +function gen_random_tree_fixed_size( |
| 69 | + node_count::Int, operators, nfeatures::Int, ::Type{T} |
| 70 | +)::Node{T} where {T} |
| 71 | + tree = make_random_leaf(nfeatures, T) |
| 72 | + cur_size = count_nodes(tree) |
| 73 | + while cur_size < node_count |
| 74 | + if cur_size == node_count - 1 # only unary operator allowed. |
| 75 | + length(operators.unaops) == 0 && break # We will go over the requested amount, so we must break. |
| 76 | + tree = append_random_op(tree, operators, nfeatures; makeNewBinOp=false) |
| 77 | + else |
| 78 | + tree = append_random_op(tree, operators, nfeatures) |
| 79 | + end |
| 80 | + cur_size = count_nodes(tree) |
| 81 | + end |
| 82 | + return tree |
| 83 | +end |
0 commit comments