fix: fix values being promoted to Float64 in problem construction

src/systems/abstractsystem.jl

@@ -733,11 +733,11 @@ function add_initialization_parameters(sys::AbstractSystem)
     defs = copy(get_defaults(sys))
     for ivar in initials
         if symbolic_type(ivar) == ScalarSymbolic()
-            defs[ivar] = zero_var(ivar)
+            defs[ivar] = false
         else
             defs[ivar] = collect(ivar)
             for scal_ivar in defs[ivar]
-                defs[scal_ivar] = zero_var(scal_ivar)
+                defs[scal_ivar] = false
             end
         end
     end

src/systems/diffeqs/abstractodesystem.jl

@@ -1541,32 +1541,6 @@ function InitializationProblem{iip, specialize}(sys::AbstractSystem,
     filter_missing_values!(parammap)
     u0map = merge(ModelingToolkit.guesses(sys), todict(guesses), u0map)
 
-    fullmap = merge(u0map, parammap)
-    u0T = Union{}
-    for sym in unknowns(isys)
-        val = fixpoint_sub(sym, fullmap)
-        symbolic_type(val) == NotSymbolic() || continue
-        u0T = promote_type(u0T, typeof(val))
-    end
-    for eq in observed(isys)
-        # ignore HACK-ed observed equations
-        symbolic_type(eq.lhs) == ArraySymbolic() && continue
-        val = fixpoint_sub(eq.lhs, fullmap)
-        symbolic_type(val) == NotSymbolic() || continue
-        u0T = promote_type(u0T, typeof(val))
-    end
-    if u0T != Union{}
-        u0T = eltype(u0T)
-        u0map = Dict(k => if v === nothing
-                         nothing
-                     elseif symbolic_type(v) == NotSymbolic() && !is_array_of_symbolics(v)
-                         v isa AbstractArray ? u0T.(v) : u0T(v)
-                     else
-                         v
-                     end
-        for (k, v) in u0map)
-    end
-
     TProb = if neqs == nunknown && isempty(unassigned_vars)
         if use_scc && neqs > 0
             if is_split(isys)

src/systems/nonlinear/initializesystem.jl

@@ -8,7 +8,7 @@ function generate_initializesystem(sys::AbstractTimeDependentSystem;
         pmap = Dict(),
         initialization_eqs = [],
         guesses = Dict(),
-        default_dd_guess = 0.0,
+        default_dd_guess = Bool(0),
         algebraic_only = false,
         check_units = true, check_defguess = false,
         name = nameof(sys), extra_metadata = (;), kwargs...)
@@ -646,10 +646,12 @@ function SciMLBase.remake_initialization_data(
 
     op, missing_unknowns, missing_pars = build_operating_point!(sys,
         u0map, pmap, defs, cmap, dvs, ps)
+    floatT = float_type_from_varmap(op)
     kws = maybe_build_initialization_problem(
         sys, op, u0map, pmap, t0, defs, guesses, missing_unknowns;
-        use_scc, initialization_eqs, allow_incomplete = true)
-    return get(kws, :initialization_data, nothing)
+        use_scc, initialization_eqs, floatT, allow_incomplete = true)
+
+    return SciMLBase.remake_initialization_data(sys, kws, newu0, t0, newp, newu0, newp)
 end
 
 function SciMLBase.late_binding_update_u0_p(

src/systems/parameter_buffer.jl

@@ -1,6 +1,6 @@
 symconvert(::Type{Symbolics.Struct{T}}, x) where {T} = convert(T, x)
-symconvert(::Type{T}, x) where {T} = convert(T, x)
-symconvert(::Type{Real}, x::Integer) = convert(Float64, x)
+symconvert(::Type{T}, x::V) where {T, V} = convert(promote_type(T, V), x)
+symconvert(::Type{Real}, x::Integer) = convert(Float16, x)
 symconvert(::Type{V}, x) where {V <: AbstractArray} = convert(V, symconvert.(eltype(V), x))
 
 struct MTKParameters{T, I, D, C, N, H}
@@ -28,7 +28,7 @@ the default behavior).
 """
 function MTKParameters(
         sys::AbstractSystem, p, u0 = Dict(); tofloat = false,
-        t0 = nothing, substitution_limit = 1000)
+        t0 = nothing, substitution_limit = 1000, floatT = nothing)
     ic = if has_index_cache(sys) && get_index_cache(sys) !== nothing
         get_index_cache(sys)
     else
@@ -56,6 +56,10 @@ function MTKParameters(
         op[get_iv(sys)] = t0
     end
 
+    if floatT === nothing
+        floatT = float(float_type_from_varmap(op))
+    end
+
     isempty(missing_pars) || throw(MissingParametersError(collect(missing_pars)))
     evaluate_varmap!(op, ps; limit = substitution_limit)
 
@@ -111,6 +115,9 @@ function MTKParameters(
         if ctype <: FnType
             ctype = fntype_to_function_type(ctype)
         end
+        if ctype == Real && floatT !== nothing
+            ctype = floatT
+        end
         val = symconvert(ctype, val)
         done = set_value(sym, val)
         if !done && Symbolics.isarraysymbolic(sym)

src/systems/problem_utils.jl

@@ -247,25 +247,6 @@ function recursive_unwrap(x::AbstractDict)
     return anydict(unwrap(k) => recursive_unwrap(v) for (k, v) in x)
 end
 
-"""
-    $(TYPEDSIGNATURES)
-
-Return the appropriate zero value for a symbolic variable representing a number or array of
-numbers. Sized array symbolics return a zero-filled array of matching size. Unsized array
-symbolics return an empty array of the appropriate `eltype`.
-"""
-function zero_var(x::Symbolic{T}) where {V <: Number, T <: Union{V, AbstractArray{V}}}
-    if Symbolics.isarraysymbolic(x)
-        if is_sized_array_symbolic(x)
-            return zeros(eltype(T), size(x))
-        else
-            return T[]
-        end
-    else
-        return zero(T)
-    end
-end
-
 """
     $(TYPEDSIGNATURES)
 
@@ -362,7 +343,7 @@ Keyword arguments:
 - `is_initializeprob, guesses`: Used to determine whether the system is missing guesses.
 """
 function better_varmap_to_vars(varmap::AbstractDict, vars::Vector;
-        tofloat = true, container_type = Array,
+        tofloat = true, container_type = Array, floatT = Nothing,
         toterm = default_toterm, promotetoconcrete = nothing, check = true,
         allow_symbolic = false, is_initializeprob = false)
     isempty(vars) && return nothing
@@ -385,6 +366,9 @@ function better_varmap_to_vars(varmap::AbstractDict, vars::Vector;
             is_initializeprob ? throw(MissingGuessError(missingsyms, missingvals)) :
             throw(UnexpectedSymbolicValueInVarmap(missingsyms[1], missingvals[1]))
         end
+        if tofloat && !(floatT == Nothing)
+            vals = floatT.(vals)
+        end
     end
 
     if container_type <: Union{AbstractDict, Tuple, Nothing, SciMLBase.NullParameters}
@@ -533,12 +517,12 @@ function (f::UpdateInitializeprob)(initializeprob, prob)
     f.setvals(initializeprob, f.getvals(prob))
 end
 
-function get_temporary_value(p)
+function get_temporary_value(p, floatT = Float64)
     stype = symtype(unwrap(p))
     return if stype == Real
-        zero(Float64)
+        zero(floatT)
     elseif stype <: AbstractArray{Real}
-        zeros(Float64, size(p))
+        zeros(floatT, size(p))
     elseif stype <: Real
         zero(stype)
     elseif stype <: AbstractArray
@@ -648,15 +632,32 @@ All other keyword arguments are forwarded to `InitializationProblem`.
 """
 function maybe_build_initialization_problem(
         sys::AbstractSystem, op::AbstractDict, u0map, pmap, t, defs,
-        guesses, missing_unknowns; implicit_dae = false, u0_constructor = identity, kwargs...)
+        guesses, missing_unknowns; implicit_dae = false,
+        u0_constructor = identity, floatT = Float64, kwargs...)
     guesses = merge(ModelingToolkit.guesses(sys), todict(guesses))
 
     if t === nothing && is_time_dependent(sys)
-        t = 0.0
+        t = zero(floatT)
     end
 
     initializeprob = ModelingToolkit.InitializationProblem{true, SciMLBase.FullSpecialize}(
         sys, t, u0map, pmap; guesses, kwargs...)
+    if state_values(initializeprob) !== nothing
+        initializeprob = remake(initializeprob; u0 = floatT.(state_values(initializeprob)))
+    end
+    initp = parameter_values(initializeprob)
+    if is_split(sys)
+        buffer, repack, _ = SciMLStructures.canonicalize(SciMLStructures.Tunable(), initp)
+        initp = repack(floatT.(buffer))
+        buffer, repack, _ = SciMLStructures.canonicalize(SciMLStructures.Initials(), initp)
+        initp = repack(floatT.(buffer))
+    elseif initp isa AbstractArray
+        initp′ = similar(initp, floatT)
+        copyto!(initp′, initp)
+        initp = initp′
+    end
+    initializeprob = remake(initializeprob; p = initp)
+
     meta = get_metadata(initializeprob.f.sys)
 
     if is_time_dependent(sys)
@@ -692,7 +693,7 @@ function maybe_build_initialization_problem(
         get(op, p, missing) === missing || continue
         p = unwrap(p)
         stype = symtype(p)
-        op[p] = get_temporary_value(p)
+        op[p] = get_temporary_value(p, floatT)
         if iscall(p) && operation(p) === getindex
             arrp = arguments(p)[1]
             op[arrp] = collect(arrp)
@@ -701,7 +702,7 @@ function maybe_build_initialization_problem(
 
     if is_time_dependent(sys)
         for v in missing_unknowns
-            op[v] = zero_var(v)
+            op[v] = get_temporary_value(v, floatT)
         end
         empty!(missing_unknowns)
     end
@@ -712,6 +713,26 @@ function maybe_build_initialization_problem(
             initializeprobpmap))
 end
 
+"""
+    $(TYPEDSIGNATURES)
+
+Calculate the floating point type to use from the given `varmap` by looking at variables
+with a constant value.
+"""
+function float_type_from_varmap(varmap, floatT = Bool)
+    for (k, v) in varmap
+        symbolic_type(v) == NotSymbolic() || continue
+        is_array_of_symbolics(v) && continue
+
+        if v isa AbstractArray
+            floatT = promote_type(floatT, eltype(v))
+        elseif v isa Real
+            floatT = promote_type(floatT, typeof(v))
+        end
+    end
+    return float(floatT)
+end
+
 """
     $(TYPEDSIGNATURES)
 
@@ -815,12 +836,19 @@ function process_SciMLProblem(
     op, missing_unknowns, missing_pars = build_operating_point!(sys,
         u0map, pmap, defs, cmap, dvs, ps)
 
+    floatT = Bool
+    if u0Type <: AbstractArray && eltype(u0Type) <: Real
+        floatT = float(eltype(u0Type))
+    else
+        floatT = float_type_from_varmap(op, floatT)
+    end
+
     if !is_time_dependent(sys) || is_initializesystem(sys)
         add_observed_equations!(u0map, obs)
     end
     if u0_constructor === identity && u0Type <: StaticArray
         u0_constructor = vals -> SymbolicUtils.Code.create_array(
-            u0Type, eltype(vals), Val(1), Val(length(vals)), vals...)
+            u0Type, floatT, Val(1), Val(length(vals)), vals...)
     end
     if build_initializeprob
         kws = maybe_build_initialization_problem(
@@ -830,7 +858,7 @@ function process_SciMLProblem(
             warn_cyclic_dependency, check_units = check_initialization_units,
             circular_dependency_max_cycle_length, circular_dependency_max_cycles, use_scc,
             force_time_independent = force_initialization_time_independent, algebraic_only, allow_incomplete,
-            u0_constructor)
+            u0_constructor, floatT)
 
         kwargs = merge(kwargs, kws)
     end
@@ -858,7 +886,7 @@ function process_SciMLProblem(
     evaluate_varmap!(op, dvs; limit = substitution_limit)
 
     u0 = better_varmap_to_vars(
-        op, dvs; tofloat,
+        op, dvs; tofloat, floatT,
         container_type = u0Type, allow_symbolic = symbolic_u0, is_initializeprob)
 
     if u0 !== nothing
@@ -882,7 +910,7 @@ function process_SciMLProblem(
     end
     evaluate_varmap!(op, ps; limit = substitution_limit)
     if is_split(sys)
-        p = MTKParameters(sys, op)
+        p = MTKParameters(sys, op; floatT = floatT)
     else
         p = better_varmap_to_vars(op, ps; tofloat, container_type = pType)
     end
@@ -898,6 +926,16 @@ function process_SciMLProblem(
         du0 = nothing
     end
 
+    if build_initializeprob
+        t0 = t
+        if is_time_dependent(sys) && t0 === nothing
+            t0 = zero(floatT)
+        end
+        initialization_data = SciMLBase.remake_initialization_data(
+            kwargs.initialization_data, kwargs, u0, t0, p, u0, p)
+        kwargs = merge(kwargs,)
+    end
+
     f = constructor(sys, dvs, ps, u0; p = p,
         eval_expression = eval_expression,
         eval_module = eval_module,

test/initial_values.jl

@@ -252,3 +252,16 @@ end
     ps = [p => [4.0, 5.0]]
     @test_nowarn NonlinearProblem(nlsys, u0, ps)
 end
+
+@testset "Issue#3553: Retain `Float32` initial values" begin
+    @parameters p d
+    @variables X(t)
+    eqs = [D(X) ~ p - d * X]
+    @mtkbuild osys = ODESystem(eqs, t)
+    u0 = [X => 1.0f0]
+    ps = [p => 1.0f0, d => 2.0f0]
+    oprob = ODEProblem(osys, u0, (0.0f0, 1.0f0), ps)
+    sol = solve(oprob)
+    @test eltype(oprob.u0) == Float32
+    @test eltype(eltype(sol.u)) == Float32
+end