make indicators nothing instead of tuple of nothing

src/analysis/sliding_window.jl

@@ -67,7 +67,9 @@ function SlidingWindowConfig(
     )
     indicators, change_metrics = sanitycheck_metrics(indicators, change_metrics)
     # Last step: precomputable functions, if any
-    indicators = map(f -> precompute(f, 1:T(width_ind)), indicators)
+    if !isnothing(indicators)
+        indicators = map(f -> precompute(f, 1:T(width_ind)), indicators)
+    end
     change_metrics = map(f -> precompute(f, 1:T(width_cha)), change_metrics)
 
     return SlidingWindowConfig(
@@ -77,13 +79,13 @@ function SlidingWindowConfig(
 end
 
 function sanitycheck_metrics(indicators, change_metrics)
-    if !(indicators isa Tuple)
-        indicators = (indicators,)
-    end
     if !(change_metrics isa Tuple)
         change_metrics = (change_metrics,)
     end
-    if length(change_metrics) ≠ length(indicators) && indicators !== (nothing, )
+    if indicators isa Function
+        indicators = (indicators, )
+    end
+    if !isnothing(indicators) && (length(change_metrics) ≠ length(indicators))
         throw(ArgumentError("The amount of change metrics and indicators must match."))
     end
     return indicators, change_metrics
@@ -97,7 +99,7 @@ end
 function estimate_indicator_changes(config::SlidingWindowConfig, x, t = eachindex(x))
     (; indicators, change_metrics) = config
     # initialize time vectors
-    if indicators === (nothing, )
+    if isnothing(indicators)
         # Skip indicators if they are nothing
         t_indicator = t
     else
@@ -118,7 +120,7 @@ function estimate_indicator_changes(config::SlidingWindowConfig, x, t = eachinde
 
     for i in 1:n_metrics
         # estimate indicator timeseries
-        if indicators !== (nothing, )
+        if !isnothing(indicators)
             z = view(x_indicator, :, i)
             windowmap!(indicators[i], z, x;
                 width = config.width_ind, stride = config.stride_ind

src/significance/surrogates_significance.jl

@@ -62,7 +62,7 @@ function significant_transitions(res::SlidingWindowResults, signif::SurrogatesSi
     (; x, x_indicator, x_change) = res
     (; indicators, change_metrics, width_ind, stride_ind, width_cha, stride_cha) = res.config
     (; surrogate, n, tail, rng, p, pvalues) = signif
-    n_ind = length(indicators)
+    n_ind = length(change_metrics)
     sanitycheck_tail(tail, n_ind)
 
     # Init pvalues
@@ -75,15 +75,14 @@ function significant_transitions(res::SlidingWindowResults, signif::SurrogatesSi
     seeds = rand(rng, 1:typemax(Int), Threads.nthreads())
     sgens = [surrogenerator(x, surrogate, Xoshiro(seed)) for seed in seeds]
     # Dummy vals for surrogate parallelization
-    if indicators !== (nothing, )
+    if !isnothing(indicators)
         indicator_dummys = [x_indicator[:, 1] for _ in 1:Threads.nthreads()]
     else
         indicator_dummys = [copy(x) for _ in 1:Threads.nthreads()]
     end
     change_dummys = [x_change[:, 1] for _ in 1:Threads.nthreads()]
 
     Threads.@threads for _ in 1:n
-
         id = Threads.threadid()
         s = sgens[id]()
         change_dummy = change_dummys[id]
@@ -172,8 +171,8 @@ function sanitycheck_tail(tail, n_ind)
     end
 end
 
-function choose_metrics(indicators::Tuple, change_metrics, tail, i::Int)
-    ind = indicators === (nothing, ) ? nothing : indicators[i]
+function choose_metrics(indicators, change_metrics, tail, i::Int)
+    ind = isnothing(indicators) ? nothing : indicators[i]
     tai = tail isa Symbol ? tail : tail[i]
     return ind, change_metrics[i], tai
 end