Merge pull request #1480 from AayushSabharwal/as/fix-mutation

fix: remove mutation of `BasicSymbolic`

Author: ChrisRackauckas

src/latexify_recipes.jl

@@ -216,7 +216,7 @@ function _toexpr(O)
         while num isa Term && num.f isa Differential
             deg += 1
             den *= num.f.x
-            num = num.arguments[1]
+            num = first(arguments(num))
         end
         return :(_derivative($(_toexpr(num)), $den, $deg))
     elseif op isa Integral

src/solver/ia_main.jl

@@ -33,7 +33,12 @@ function isolate(lhs, var; warns=true, conditions=[], complex_roots = true, peri
             for i in eachindex(lhs_roots)
                 for j in eachindex(rhs)
                     if iscall(lhs_roots[i]) && operation(lhs_roots[i]) == RootsOf
-                        lhs_roots[i].arguments[1] = substitute(lhs_roots[i].arguments[1], Dict(new_var=>rhs[j]), fold=false)
+                        _args = copy(parent(arguments(lhs_roots[i])))
+                        _args[1] = substitute(_args[1], Dict(new_var => rhs[j]), fold = false)
+                        T = typeof(lhs_roots[i])
+                        _op = operation(lhs_roots[i])
+                        _meta = metadata(lhs_roots[i])
+                        lhs_roots[i] = maketerm(T, _op, _args, _meta)
                         push!(roots, lhs_roots[i])
                     else
                         push!(roots, substitute(lhs_roots[i], Dict(new_var=>rhs[j]), fold=false))
@@ -86,8 +91,9 @@ function isolate(lhs, var; warns=true, conditions=[], complex_roots = true, peri
             end
 
         elseif oper === (^)
-            if any(isequal(x, var) for x in get_variables(args[1])) &&
-               n_occurrences(args[2], var) == 0 && args[2] isa Integer
+            var_in_base = any(isequal(x, var) for x in get_variables(args[1]))
+            var_in_pow = n_occurrences(args[2], var) != 0
+            if var_in_base && !var_in_pow && args[2] isa Integer
                 lhs = args[1]
                 power = args[2]
                 new_roots = []
@@ -111,11 +117,10 @@ function isolate(lhs, var; warns=true, conditions=[], complex_roots = true, peri
                 end
                 rhs = []
                 append!(rhs, new_roots)
-            elseif any(isequal(x, var) for x in get_variables(args[1])) &&
-                   n_occurrences(args[2], var) == 0
+            elseif var_in_base && !var_in_pow
                 lhs = args[1]
-                s, args[2] = filter_stuff(args[2])
-                rhs = map(sol -> term(^, sol, 1 // args[2]), rhs)
+                s, power = filter_stuff(args[2])
+                rhs = map(sol -> term(^, sol, 1 // power), rhs)
             else
                 lhs = args[2]
                 rhs = map(sol -> term(/, term(slog, sol), term(slog, args[1])), rhs)

src/solver/polynomialization.jl

@@ -43,7 +43,7 @@ function turn_to_poly(expr, var)
     expr = unwrap(expr)
     !iscall(expr) && return (expr, Dict())
 
-    args = arguments(expr)
+    args = copy(parent(arguments(expr)))
 
     sub = 0
     broken = Ref(false)
@@ -53,12 +53,12 @@ function turn_to_poly(expr, var)
         arg_oper = operation(arg)
 
         if arg_oper === (^)
-            tp = trav_pow(args, i, var, broken, sub)
+            args[i], tp = trav_pow(args[i], var, broken, sub)
             sub = isequal(tp, false) ? sub : tp
             continue
         end
         if arg_oper === (*)
-            sub = trav_mult(arg, var, broken, sub)
+            args[i], sub = trav_mult(arg, var, broken, sub)
             continue
         end
         isequal(add_sub(sub, arg, var, broken), false) && continue
@@ -77,16 +77,17 @@ function turn_to_poly(expr, var)
 
     new_var = gensym()
     new_var = (@variables $new_var)[1]
+    expr = maketerm(typeof(expr), operation(expr), args, metadata(expr))
     return ssubs(expr, Dict(sub => new_var)), Dict{Any, Any}(new_var => sub)
 end
 
 """
-    trav_pow(args, index, var, broken, sub)
+    trav_pow(arg, var, broken, sub)
 
-Traverses an argument passed from ``turn_to_poly`` if it
-satisfies ``oper === (^)``. Returns sub if changed from 0
-to a new transcendental function or its value is 
-kept the same, and false if these 2 cases do not occur.
+Traverses an argument `arg` passed from ``turn_to_poly`` if it satisfies
+``oper === (^)``. Returns the new `arg` and `sub` if `sub` is changed from 0 to a new
+transcendental function or its value is kept the same, or else `false` if these 2 cases
+do not occur.
 
 # Arguments
 - args: The original arguments array of the expression passed to ``turn_to_poly``
@@ -97,20 +98,20 @@ kept the same, and false if these 2 cases do not occur.
 
 # Examples
 ```jldoctest
-julia> trav_pow([unwrap(9^x)], 1, x, Ref(false), 3^x)
-3^x
+julia> trav_pow(unwrap(9^x), x, Ref(false), 3^x)
+(9^x, 3^x)
 
-julia> trav_pow([unwrap(x^2)], 1, x, Ref(false), 3^x)
-false
+julia> trav_pow(unwrap(x^2), x, Ref(false), 3^x)
+(x^2, false)
 ```
 """
-function trav_pow(args, index, var, broken, sub)
-    args_arg = arguments(args[index])
+function trav_pow(arg, var, broken, sub)
+    args_arg = arguments(arg)
     base = args_arg[1]
     power = args_arg[2]
 
     # case 1: log(x)^2 .... 9^x = 3^2^x = 3^2x = (3^x)^2
-    !isequal(add_sub(sub, base, var, broken), false) && power isa Integer && return base
+    !isequal(add_sub(sub, base, var, broken), false) && power isa Integer && return arg, base
 
     # case 2: int^f(x)
     # n_func_occ may not be strictly 1, we could attempt attracting it after solving
@@ -122,21 +123,20 @@ function trav_pow(args, index, var, broken, sub)
         sub = isequal(sub, 0) ? new_b : sub
         if !isequal(sub, new_b)
             broken[] = true
-            return false
+            return arg, false
         end
         new_b = term(^, new_b, p)
-        args[index] = new_b
-        return sub
+        return new_b, sub
     end
 
-    return false
+    return arg, false
 end
 
 """
     trav_mult(arg, var, broken, sub)
 
 Traverses an argument passed from ``turn_to_poly`` if it
-satisfies ``oper === (*)``. Returns sub whether its changed from 0
+satisfies ``oper === (*)``. Returns the new `arg` and `sub` if its changed from 0
 to a new transcendental function or its value is 
 kept the same, but changes broken if these 2 cases do not occur. It
 traverses the * argument by sub_arg and compares it to sub using
@@ -151,32 +151,33 @@ the function ``add_sub``
 # Examples
 ```jldoctest
 julia> trav_mult(unwrap(9*log(x)), x, Ref(false), log(x))
-log(x)
+(9log(x), log(x))
 
 julia> trav_mult(unwrap(9*log(x)^2), x, Ref(false), log(x))
-log(x)
+(9(log(x)^2), log(x))
 
 # value of broken is changed here to true
 julia> trav_mult(unwrap(9*log(x+1)), x, Ref(false), log(x))
-log(x)
+(9log(x + 1), log(x))
 ```
 """
 function trav_mult(arg, var, broken, sub)
-    args_arg = arguments(arg)
+    args_arg = copy(parent(arguments(arg)))
     for (i, arg2) in enumerate(args_arg)
         !iscall(arg2) && continue
 
         oper = operation(arg2)
         if oper === (^)
-            tp = trav_pow(args_arg, i, var, broken, sub)
+            args_arg[i], tp = trav_pow(args_arg[i], var, broken, sub)
             sub = isequal(tp, false) ? sub : tp
             continue
         end
 
         isequal(add_sub(sub, arg2, var, broken), false) && continue
         sub = arg2
     end
-    return sub
+    arg = maketerm(typeof(arg), operation(arg), args_arg, metadata(arg))
+    return arg, sub
 end
 
 """

src/solver/preprocess.jl

@@ -116,7 +116,7 @@ function _filter_poly(expr, var)
         return filter_stuff(expr)
     end
 
-    args = arguments(expr)
+    args = copy(parent(arguments(expr)))
     if expr isa ComplexTerm
         subs1, subs2 = Dict(), Dict()
         expr1, expr2 = 0, 0
@@ -165,7 +165,7 @@ function _filter_poly(expr, var)
         end
 
         oper = operation(arg)
-        monomial = arguments(arg)
+        monomial = copy(parent(arguments(arg)))
         if oper === (^)
             if any(arg -> isequal(arg, var), monomial)
                 continue
@@ -175,6 +175,7 @@ function _filter_poly(expr, var)
             subs2, monomial[2] = _filter_poly(monomial[2], var)
 
             merge!(subs, merge(subs1, subs2))
+            args[i] = maketerm(typeof(arg), oper, monomial, metadata(arg))
             continue
         end
 
@@ -196,6 +197,7 @@ function _filter_poly(expr, var)
                 merge!(subs_of_monom, new_subs)
             end
             merge!(subs, subs_of_monom)
+            args[i] = maketerm(typeof(arg), oper, monomial, metadata(arg))
             continue
         end
 
@@ -208,9 +210,9 @@ function _filter_poly(expr, var)
         end
     end
 
-    args = map(unwrap, arguments(expr))
+    args = map(unwrap, args)
     oper = operation(expr)
-    expr = term(oper, args...)
+    expr = maketerm(typeof(expr), oper, args, metadata(expr))
     return subs, expr
 end
 

src/solver/solve_helpers.jl

@@ -116,10 +116,11 @@ function bigify(n)
 
     if n isa SymbolicUtils.BasicSymbolic
         !iscall(n) && return n
-        args = arguments(n)
+        args = copy(parent(arguments(n)))
         for i in eachindex(args)
             args[i] = bigify(args[i])
         end
+        n = maketerm(typeof(n), operation(n), args, metadata(n))
         return n
     end