refactor: rewrite parameter timeseries interface, indexing

- some new, some deleted interface methods
- extensive validation for input values
- consistency with getu and getp
- proper error messages

Author: AayushSabharwal

src/SymbolicIndexingInterface.jl

@@ -12,18 +12,19 @@ export ScalarSymbolic, ArraySymbolic, NotSymbolic, symbolic_type, hasname, getna
 include("trait.jl")
 
 export is_variable, variable_index, variable_symbols, is_parameter, parameter_index,
+       is_timeseries_parameter, timeseries_parameter_index, ParameterTimeseriesIndex,
        parameter_symbols, is_independent_variable, independent_variable_symbols,
-       is_observed,
-       observed, is_time_dependent, constant_structure, symbolic_container,
-       all_variable_symbols,
-       all_symbols, solvedvariables, allvariables, default_values, symbolic_evaluate
+       is_observed, observed, parameter_observed, ParameterObservedFunction,
+       is_time_dependent, constant_structure, symbolic_container,
+       all_variable_symbols, all_symbols, solvedvariables, allvariables, default_values,
+       symbolic_evaluate
 include("index_provider_interface.jl")
 
 export SymbolCache
 include("symbol_cache.jl")
 
 export parameter_values, set_parameter!, finalize_parameters_hook!,
-       parameter_values_at_time, parameter_values_at_state_time, parameter_timeseries,
+       get_parameter_timeseries_collection, with_updated_parameter_timeseries_values,
        state_values, set_state!, current_time
 include("value_provider_interface.jl")
 

src/index_provider_interface.jl

@@ -53,6 +53,66 @@ Return the index of the given parameter `sym` in `indp`, or `nothing` otherwise.
 """
 parameter_index(indp, sym) = parameter_index(symbolic_container(indp), sym)
 
+"""
+    is_timeseries_parameter(indp, sym)
+
+Check whether the given `sym` is a timeseries parameter in `indp`.
+"""
+function is_timeseries_parameter(indp, sym)
+    if hasmethod(symbolic_container, Tuple{typeof(indp)})
+        is_timeseries_parameter(symbolic_container(indp), sym)
+    else
+        return false
+    end
+end
+
+"""
+    struct ParameterTimeseriesIndex
+    function ParameterTimeseriesIndex(timeseries_idx, parameter_idx)
+
+A struct storing the index of the timeseries of a timeseries parameter in a parameter
+timeseries object. `timeseries_idx` refers to an index that identifies the timeseries
+that the parameter belongs to. `parameter_idx` refers to the index of the parameter's
+timeseries in that timeseries object. Note that `parameter_idx` may be different from
+the object returned by [`parameter_index`](@ref) for a given parameter. The two fields in
+this struct are `timeseries_idx` and `parameter_idx`.
+"""
+struct ParameterTimeseriesIndex{T, I}
+    timeseries_idx::T
+    parameter_idx::I
+end
+
+"""
+    timeseries_parameter_index(indp, sym)
+
+Return the index of timeseries parameter `sym` in `indp`. Must return this index as a
+[`ParameterTimeseriesIndex`](@ref) object. Return `nothing` if `sym` is not a timeseries
+parameter in `indp`. Defaults to returning `nothing`. Respects the
+[`symbolic_container`](@ref) fallback for `indp` if present.
+"""
+function timeseries_parameter_index(indp, sym)
+    if hasmethod(symbolic_container, Tuple{typeof(indp)})
+        timeseries_parameter_index(symbolic_container(indp), sym)
+    else
+        return nothing
+    end
+end
+
+struct ParameterObservedFunction{I, F <: Function}
+    timeseries_idx::I
+    observed_fn::F
+end
+
+"""
+    parameter_observed(indp, sym)
+
+Return the observed function of `sym` in `indp`. The returned function must have the
+signature `(p, t) -> [values...]` where `p` is the parameter object and `t` is the
+current time. If `!is_time_dependent(indp)` then the returned function must have the
+signature `(p) -> [values...]`.
+"""
+parameter_observed(indp, sym) = parameter_observed(symbolic_container(indp), sym)
+
 """
     parameter_symbols(indp)
 
@@ -88,7 +148,7 @@ is_observed(indp, sym) = is_observed(symbolic_container(indp), sym)
 
 Return the observed function of the given `sym` in `indp`. The returned function should
 have the signature `(u, p) -> [values...]` where `u` and `p` is the current state and
-parameter vector, respectively. If `istimedependent(indp) == true`, the function should
+parameter object, respectively. If `istimedependent(indp) == true`, the function should
 accept the current time `t` as its third parameter. If `constant_structure(indp) == false`,
 `observed` accepts a third parameter, which can either be a vector of symbols indicating
 the order of states or a time index, which identifies the order of states. This function