Merge pull request #50 from SymbolicML/lighter-types

Switch to UInt8/UInt16 for Node fields

Author: MilesCranmer

Project.toml

@@ -1,7 +1,7 @@
 name = "DynamicExpressions"
 uuid = "a40a106e-89c9-4ca8-8020-a735e8728b6b"
 authors = ["MilesCranmer <miles.cranmer@gmail.com>"]
-version = "0.12.3"
+version = "0.13.0"
 
 [deps]
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"

benchmark/benchmark_utils.jl

@@ -8,13 +8,11 @@ function random_node(tree::Node{T})::Node{T} where {T}
     if tree.degree == 0
         return tree
     end
-    b = 0
-    c = 0
-    if tree.degree >= 1
-        b = count_nodes(tree.l)
-    end
-    if tree.degree == 2
-        c = count_nodes(tree.r)
+    b = count_nodes(tree.l)
+    c = if tree.degree == 2
+        count_nodes(tree.r)
+    else
+        0
     end
 
     i = rand(1:(1 + b + c))
@@ -27,7 +25,7 @@ function random_node(tree::Node{T})::Node{T} where {T}
     return random_node(tree.r)
 end
 
-function make_random_leaf(nfeatures::Int, ::Type{T})::Node{T} where {T}
+function make_random_leaf(nfeatures::Integer, ::Type{T})::Node{T} where {T}
     if rand() > 0.5
         return Node(; val=randn(T))
     else
@@ -37,7 +35,7 @@ end
 
 # Add a random unary/binary operation to the end of a tree
 function append_random_op(
-    tree::Node{T}, operators, nfeatures::Int; makeNewBinOp::Union{Bool,Nothing}=nothing
+    tree::Node{T}, operators, nfeatures::Integer; makeNewBinOp::Union{Bool,Nothing}=nothing
 )::Node{T} where {T}
     nuna = length(operators.unaops)
     nbin = length(operators.binops)
@@ -66,7 +64,7 @@ function append_random_op(
 end
 
 function gen_random_tree_fixed_size(
-    node_count::Int, operators, nfeatures::Int, ::Type{T}
+    node_count::Integer, operators, nfeatures::Integer, ::Type{T}
 )::Node{T} where {T}
     tree = make_random_leaf(nfeatures, T)
     cur_size = count_nodes(tree)

docs/src/eval.md

@@ -90,7 +90,7 @@ all variables (or, all constants). Both use forward-mode automatic, but use
 `Zygote.jl` to compute derivatives of each operator, so this is very efficient.
 
 ```@docs
-eval_diff_tree_array(tree::Node{T}, cX::AbstractMatrix{T}, operators::OperatorEnum, direction::Int) where {T<:Number}
+eval_diff_tree_array(tree::Node{T}, cX::AbstractMatrix{T}, operators::OperatorEnum, direction::Integer) where {T<:Number}
 eval_grad_tree_array(tree::Node{T}, cX::AbstractMatrix{T}, operators::OperatorEnum; turbo::Bool=false, variable::Bool=false) where {T<:Number}
 ```
 

docs/src/types.md

@@ -55,8 +55,8 @@ There are a variety of constructors for `Node` objects, including:
 
 ```@docs
 Node(::Type{T}; val=nothing, feature::Integer=nothing) where {T}
-Node(op::Int, l::Node)
-Node(op::Int, l::Node, r::Node)
+Node(op::Integer, l::Node)
+Node(op::Integer, l::Node, r::Node)
 Node(var_string::String)
 ```
 

ext/DynamicExpressionsSymbolicUtilsExt.jl

@@ -27,9 +27,9 @@ function parse_tree_to_eqs(
         return SymbolicUtils.Sym{LiteralReal}(Symbol("x$(tree.feature)"))
     end
     # Collect the next children
-    children = tree.degree >= 2 ? (tree.l, tree.r) : (tree.l,)
+    children = tree.degree == 2 ? (tree.l, tree.r) : (tree.l,)
     # Get the operation
-    op = tree.degree > 1 ? operators.binops[tree.op] : operators.unaops[tree.op]
+    op = tree.degree == 2 ? operators.binops[tree.op] : operators.unaops[tree.op]
     # Create an N tuple of Numbers for each argument
     dtypes = map(x -> Number, 1:(tree.degree))
     #
@@ -228,7 +228,7 @@ function multiply_powers(
         @return_on_false complete eqn
         @return_on_false isgood(l) eqn
         n = args[2]
-        if typeof(n) <: Int
+        if typeof(n) <: Integer
             if n == 1
                 return l, true
             elseif n == -1

src/Equation.jl

@@ -5,6 +5,7 @@ import ..UtilsModule: @memoize_on, @with_memoize, deprecate_varmap
 
 const DEFAULT_NODE_TYPE = Float32
 
+#! format: off
 """
     Node{T}
 
@@ -15,16 +16,16 @@ nodes, you can evaluate or print a given expression.
 
 # Fields
 
-- `degree::Int`: Degree of the node. 0 for constants, 1 for
+- `degree::UInt8`: Degree of the node. 0 for constants, 1 for
     unary operators, 2 for binary operators.
 - `constant::Bool`: Whether the node is a constant.
 - `val::T`: Value of the node. If `degree==0`, and `constant==true`,
     this is the value of the constant. It has a type specified by the
     overall type of the `Node` (e.g., `Float64`).
-- `feature::Int` (optional): Index of the feature to use in the
+- `feature::UInt16`: Index of the feature to use in the
     case of a feature node. Only used if `degree==0` and `constant==false`. 
     Only defined if `degree == 0 && constant == false`.
-- `op::Int`: If `degree==1`, this is the index of the operator
+- `op::UInt8`: If `degree==1`, this is the index of the operator
     in `operators.unaops`. If `degree==2`, this is the index of the
     operator in `operators.binops`. In other words, this is an enum
     of the operators, and is dependent on the specific `OperatorEnum`
@@ -36,36 +37,32 @@ nodes, you can evaluate or print a given expression.
     argument to the binary operator.
 """
 mutable struct Node{T}
-    degree::Int  # 0 for constant/variable, 1 for cos/sin, 2 for +/* etc.
+    degree::UInt8  # 0 for constant/variable, 1 for cos/sin, 2 for +/* etc.
     constant::Bool  # false if variable
     val::Union{T,Nothing}  # If is a constant, this stores the actual value
     # ------------------- (possibly undefined below)
-    feature::Int  # If is a variable (e.g., x in cos(x)), this stores the feature index.
-    op::Int  # If operator, this is the index of the operator in operators.binary_operators, or operators.unary_operators
+    feature::UInt16  # If is a variable (e.g., x in cos(x)), this stores the feature index.
+    op::UInt8  # If operator, this is the index of the operator in operators.binops, or operators.unaops
     l::Node{T}  # Left child node. Only defined for degree=1 or degree=2.
     r::Node{T}  # Right child node. Only defined for degree=2. 
 
     #################
     ## Constructors:
     #################
-    Node(d::Int, c::Bool, v::_T) where {_T} = new{_T}(d, c, v)
-    Node(::Type{_T}, d::Int, c::Bool, v::_T) where {_T} = new{_T}(d, c, v)
-    Node(::Type{_T}, d::Int, c::Bool, v::Nothing, f::Int) where {_T} = new{_T}(d, c, v, f)
-    function Node(d::Int, c::Bool, v::Nothing, f::Int, o::Int, l::Node{_T}) where {_T}
-        return new{_T}(d, c, v, f, o, l)
-    end
-    function Node(
-        d::Int, c::Bool, v::Nothing, f::Int, o::Int, l::Node{_T}, r::Node{_T}
-    ) where {_T}
-        return new{_T}(d, c, v, f, o, l, r)
-    end
+    Node(d::Integer, c::Bool, v::_T) where {_T} = new{_T}(UInt8(d), c, v)
+    Node(::Type{_T}, d::Integer, c::Bool, v::_T) where {_T} = new{_T}(UInt8(d), c, v)
+    Node(::Type{_T}, d::Integer, c::Bool, v::Nothing, f::Integer) where {_T} = new{_T}(UInt8(d), c, v, UInt16(f))
+    Node(d::Integer, c::Bool, v::Nothing, f::Integer, o::Integer, l::Node{_T}) where {_T} = new{_T}(UInt8(d), c, v, UInt16(f), UInt8(o), l)
+    Node(d::Integer, c::Bool, v::Nothing, f::Integer, o::Integer, l::Node{_T}, r::Node{_T}) where {_T} = new{_T}(UInt8(d), c, v, UInt16(f), UInt8(o), l, r)
+
 end
 ################################################################################
+#! format: on
 
 include("base.jl")
 
 """
-    Node([::Type{T}]; val=nothing, feature::Int=nothing) where {T}
+    Node([::Type{T}]; val=nothing, feature::Union{Integer,Nothing}=nothing) where {T}
 
 Create a leaf node: either a constant, or a variable.
 
@@ -115,18 +112,18 @@ function Node(
 end
 
 """
-    Node(op::Int, l::Node)
+    Node(op::Integer, l::Node)
 
 Apply unary operator `op` (enumerating over the order given) to `Node` `l`
 """
-Node(op::Int, l::Node{T}) where {T} = Node(1, false, nothing, 0, op, l)
+Node(op::Integer, l::Node{T}) where {T} = Node(1, false, nothing, 0, op, l)
 
 """
-    Node(op::Int, l::Node, r::Node)
+    Node(op::Integer, l::Node, r::Node)
 
 Apply binary operator `op` (enumerating over the order given) to `Node`s `l` and `r`
 """
-function Node(op::Int, l::Node{T1}, r::Node{T2}) where {T1,T2}
+function Node(op::Integer, l::Node{T1}, r::Node{T2}) where {T1,T2}
     # Get highest type:
     if T1 != T2
         T = promote_type(T1, T2)
@@ -141,7 +138,7 @@ end
 
 Create a variable node, using the format `"x1"` to mean feature 1
 """
-Node(var_string::String) = Node(; feature=parse(Int, var_string[2:end]))
+Node(var_string::String) = Node(; feature=parse(UInt16, var_string[2:end]))
 
 """
     Node(var_string::String, variable_names::Array{String, 1})
@@ -261,7 +258,7 @@ Convert an equation to a string.
 
 # Keyword Arguments
 - `bracketed`: (optional) whether to put brackets around the outside.
-- `f_variable`: (optional) function to convert a variable to a string, of the form `(feature::Int, variable_names)`.
+- `f_variable`: (optional) function to convert a variable to a string, of the form `(feature::UInt8, variable_names)`.
 - `f_constant`: (optional) function to convert a constant to a string, of the form `(val, bracketed::Bool)`
 - `variable_names::Union{Array{String, 1}, Nothing}=nothing`: (optional) what variables to print for each feature.
 """

src/EquationUtils.jl

@@ -46,15 +46,15 @@ has_constants(tree::Node) = any(is_node_constant, tree)
 
 Check if a tree has any operators.
 """
-has_operators(tree::Node) = tree.degree !== 0
+has_operators(tree::Node) = tree.degree != 0
 
 """
     is_constant(tree::Node)::Bool
 
 Check if an expression is a constant numerical value, or
 whether it depends on input features.
 """
-is_constant(tree::Node) = all(t -> t.degree !== 0 || t.constant, tree)
+is_constant(tree::Node) = all(t -> t.degree != 0 || t.constant, tree)
 
 """
     get_constants(tree::Node{T})::Vector{T} where {T}
@@ -92,25 +92,25 @@ end
 # This will mirror a Node struct, rather
 # than adding a new attribute to Node.
 mutable struct NodeIndex
-    constant_index::Int  # Index of this constant (if a constant exists here)
+    constant_index::UInt16  # Index of this constant (if a constant exists here)
     l::NodeIndex
     r::NodeIndex
 
     NodeIndex() = new()
 end
 
 function index_constants(tree::Node)::NodeIndex
-    return index_constants(tree, 0)
+    return index_constants(tree, UInt16(0))
 end
 
-function index_constants(tree::Node, left_index::Int)::NodeIndex
+function index_constants(tree::Node, left_index)::NodeIndex
     index_tree = NodeIndex()
     index_constants!(tree, index_tree, left_index)
     return index_tree
 end
 
 # Count how many constants to the left of this node, and put them in a tree
-function index_constants!(tree::Node, index_tree::NodeIndex, left_index::Int)
+function index_constants!(tree::Node, index_tree::NodeIndex, left_index)
     if tree.degree == 0
         if tree.constant
             index_tree.constant_index = left_index + 1

src/EvaluateEquationDerivative.jl

@@ -18,7 +18,7 @@ function assert_autodiff_enabled(operators::OperatorEnum)
 end
 
 """
-    eval_diff_tree_array(tree::Node{T}, cX::AbstractMatrix{T}, operators::OperatorEnum, direction::Int; turbo::Bool=false)
+    eval_diff_tree_array(tree::Node{T}, cX::AbstractMatrix{T}, operators::OperatorEnum, direction::Integer; turbo::Bool=false)
 
 Compute the forward derivative of an expression, using a similar
 structure and optimization to eval_tree_array. `direction` is the index of a particular
@@ -31,7 +31,7 @@ respect to `x1`.
 - `cX::AbstractMatrix{T}`: The data matrix, with each column being a data point.
 - `operators::OperatorEnum`: The operators used to create the `tree`. Note that `operators.enable_autodiff`
     must be `true`. This is needed to create the derivative operations.
-- `direction::Int`: The index of the variable to take the derivative with respect to.
+- `direction::Integer`: The index of the variable to take the derivative with respect to.
 - `turbo::Bool`: Use `LoopVectorization.@turbo` for faster evaluation.
 
 # Returns
@@ -43,7 +43,7 @@ function eval_diff_tree_array(
     tree::Node{T},
     cX::AbstractMatrix{T},
     operators::OperatorEnum,
-    direction::Int;
+    direction::Integer;
     turbo::Bool=false,
 )::Tuple{AbstractVector{T},AbstractVector{T},Bool} where {T<:Number}
     assert_autodiff_enabled(operators)
@@ -57,7 +57,7 @@ function eval_diff_tree_array(
     tree::Node{T1},
     cX::AbstractMatrix{T2},
     operators::OperatorEnum,
-    direction::Int;
+    direction::Integer;
     turbo::Bool=false,
 ) where {T1<:Number,T2<:Number}
     T = promote_type(T1, T2)
@@ -71,7 +71,7 @@ function _eval_diff_tree_array(
     tree::Node{T},
     cX::AbstractMatrix{T},
     operators::OperatorEnum,
-    direction::Int,
+    direction::Integer,
     ::Val{turbo},
 )::Tuple{AbstractVector{T},AbstractVector{T},Bool} where {T<:Number,turbo}
     evaluation, derivative, complete = if tree.degree == 0
@@ -102,7 +102,7 @@ function _eval_diff_tree_array(
 end
 
 function diff_deg0_eval(
-    tree::Node{T}, cX::AbstractMatrix{T}, direction::Int
+    tree::Node{T}, cX::AbstractMatrix{T}, direction::Integer
 )::Tuple{AbstractVector{T},AbstractVector{T},Bool} where {T<:Number}
     const_part = deg0_eval(tree, cX)[1]
     derivative_part = if ((!tree.constant) && tree.feature == direction)
@@ -119,7 +119,7 @@ function diff_deg1_eval(
     op::F,
     diff_op::dF,
     operators::OperatorEnum,
-    direction::Int,
+    direction::Integer,
     ::Val{turbo},
 )::Tuple{AbstractVector{T},AbstractVector{T},Bool} where {T<:Number,F,dF,turbo}
     (cumulator, dcumulator, complete) = _eval_diff_tree_array(
@@ -144,7 +144,7 @@ function diff_deg2_eval(
     op::F,
     diff_op::dF,
     operators::OperatorEnum,
-    direction::Int,
+    direction::Integer,
     ::Val{turbo},
 )::Tuple{AbstractVector{T},AbstractVector{T},Bool} where {T<:Number,F,dF,turbo}
     (cumulator, dcumulator, complete) = _eval_diff_tree_array(
@@ -200,7 +200,7 @@ function eval_grad_tree_array(
 )::Tuple{AbstractVector{T},AbstractMatrix{T},Bool} where {T<:Number}
     assert_autodiff_enabled(operators)
     n_gradients = variable ? size(cX, 1) : count_constants(tree)
-    index_tree = index_constants(tree, 0)
+    index_tree = index_constants(tree, UInt16(0))
     return eval_grad_tree_array(
         tree,
         Val(n_gradients),

src/OperatorEnumConstruction.jl

@@ -7,7 +7,7 @@ import ..EvaluateEquationDerivativeModule: eval_grad_tree_array, _zygote_gradien
 import ..EvaluationHelpersModule: _grad_evaluator
 
 """Used to set a default value for `operators` for ease of use."""
-@enum AvailableOperatorTypes begin
+@enum AvailableOperatorTypes::UInt8 begin
     IsNothing
     IsOperatorEnum
     IsGenericOperatorEnum
@@ -19,8 +19,8 @@ end
 
 const LATEST_OPERATORS = Ref{Union{Nothing,AbstractOperatorEnum}}(nothing)
 const LATEST_OPERATORS_TYPE = Ref{AvailableOperatorTypes}(IsNothing)
-const LATEST_UNARY_OPERATOR_MAPPING = Dict{Function,Int}()
-const LATEST_BINARY_OPERATOR_MAPPING = Dict{Function,Int}()
+const LATEST_UNARY_OPERATOR_MAPPING = Dict{Function,fieldtype(Node{Float64}, :op)}()
+const LATEST_BINARY_OPERATOR_MAPPING = Dict{Function,fieldtype(Node{Float64}, :op)}()
 const ALREADY_DEFINED_UNARY_OPERATORS = (;
     operator_enum=Dict{Function,Bool}(), generic_operator_enum=Dict{Function,Bool}()
 )

src/base.jl

@@ -52,9 +52,9 @@ julia> tree_mapreduce(t -> 1, (p, c...) -> p + max(c...), tree)  # compute depth
 5
 
 julia> tree_mapreduce(vcat, tree) do t
-    t.degree == 2 ? [t.op] : Int[]
+    t.degree == 2 ? [t.op] : UInt8[]
 end  # Get list of binary operators used. (regular mapreduce also works)
-2-element Vector{Int64}:
+2-element Vector{UInt8}:
  1
  2