wip: better parameter indexing

Author: AayushSabharwal

docs/src/api.md

@@ -32,6 +32,20 @@ allvariables
 observed
 ```
 
+#### Parameter timeseries
+
+If the index provider contains parameters that change during the course of the simulation
+at discrete intervals, it must implement the following methods to ensure correct
+functioning of [`getu`](@ref) and [`getp`](@ref) for value providers that save the parameter
+timeseries. Note that there can be multiple parameter timeseries, in case different parameters
+change at different times.
+
+```@docs
+is_timeseries_parameter
+timeseries_parameter_index
+ParameterTimeseriesIndex
+```
+
 ## Value provider interface
 
 ### State indexing
@@ -67,8 +81,8 @@ correct functioning of [`getu`](@ref) and [`getp`](@ref).
 ```@docs
 is_parameter_timeseries
 parameter_timeseries
-parameter_values_at_time
 parameter_values_at_state_time
+parameter_timeseries_at_state_time
 ```
 
 ### Batched Queries and Updates

src/SymbolicIndexingInterface.jl

@@ -12,19 +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, 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,
-       state_values, set_state!, current_time
+       parameter_values_at_state_time, parameter_timeseries,
+       parameter_timeseries_at_state_time, state_values, set_state!, current_time
 include("value_provider_interface.jl")
 
 export getp, setp
@@ -39,6 +39,9 @@ include("batched_interface.jl")
 export ProblemState
 include("problem_state.jl")
 
+export ParameterTimeseriesCollection
+include("parameter_timeseries_collection.jl")
+
 export ParameterIndexingProxy
 include("parameter_indexing_proxy.jl")
 

src/index_provider_interface.jl

@@ -53,6 +53,51 @@ 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
+        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
+        nothing
+    end
+end
+
 """
     parameter_symbols(indp)