throw error if early number

src/dense/generic_dense.jl

@@ -103,6 +103,7 @@ times ts (sorted), with values timeseries and derivatives ks
   idx = sortperm(tvals,rev=tdir<0)
   i = 2 # Start the search thinking it's between ts[1] and ts[2]
   tvals[idx[end]] > ts[end] && error("Solution interpolation cannot extrapolate past the final timepoint. Either solve on a longer timespan or use the local extrapolation from the integrator interface.")
+  tvals[idx[1]] < ts[1] && error("Solution interpolation cannot extrapolate before the first timepoint. Either start solving earlier or use the local extrapolation from the integrator interface.")
   if idxs == nothing
     if (eltype(timeseries) <: AbstractArray) && !(eltype(timeseries) <: Array)
       vals = Vector{Vector{eltype(first(timeseries))}}(length(tvals))
@@ -163,6 +164,7 @@ times ts (sorted), with values timeseries and derivatives ks
   idx = sortperm(tvals,rev=tdir<0)
   i = 2 # Start the search thinking it's between ts[1] and ts[2]
   tvals[idx[end]] > ts[end] && error("Solution interpolation cannot extrapolate past the final timepoint. Either solve on a longer timespan or use the local extrapolation from the integrator interface.")
+  tvals[idx[1]] < ts[1] && error("Solution interpolation cannot extrapolate before the first timepoint. Either start solving earlier or use the local extrapolation from the integrator interface.")
   @inbounds for j in idx
     t = tvals[j]
     i = searchsortedfirst(@view(ts[@view(notsaveat_idxs[i:end])]),t,rev=tdir<0)+i-1 # It's in the interval ts[i-1] to ts[i]
@@ -220,6 +222,7 @@ times ts (sorted), with values timeseries and derivatives ks
 @inline function ode_interpolation(tval::Number,id,idxs,deriv)
   @unpack ts,timeseries,ks,f,notsaveat_idxs,cache = id
   tval > ts[end] && error("Solution interpolation cannot extrapolate past the final timepoint. Either solve on a longer timespan or use the local extrapolation from the integrator interface.")
+  tval < ts[1] && error("Solution interpolation cannot extrapolate before the first timepoint. Either start solving earlier or use the local extrapolation from the integrator interface.")
   tdir = sign(ts[end]-ts[1])
   @inbounds i = searchsortedfirst(@view(ts[notsaveat_idxs]),tval,rev=tdir<0) # It's in the interval ts[i-1] to ts[i]
   @inbounds if ts[notsaveat_idxs[i]] == tval
@@ -264,6 +267,7 @@ times ts (sorted), with values timeseries and derivatives ks
 @inline function ode_interpolation!(out,tval::Number,id,idxs,deriv)
   @unpack ts,timeseries,ks,f,notsaveat_idxs,cache = id
   tval > ts[end] && error("Solution interpolation cannot extrapolate past the final timepoint. Either solve on a longer timespan or use the local extrapolation from the integrator interface.")
+  tval < ts[1] && error("Solution interpolation cannot extrapolate before the first timepoint. Either start solving earlier or use the local extrapolation from the integrator interface.")
   tdir = sign(ts[end]-ts[1])
   @inbounds i = searchsortedfirst(@view(ts[notsaveat_idxs]),tval,rev=tdir<0) # It's in the interval ts[i-1] to ts[i]
   @inbounds if ts[notsaveat_idxs[i]] == tval