diff --git a/ho_basis.jl b/ho_basis.jl
index 3944eae..84c56f8 100644
--- a/ho_basis.jl
+++ b/ho_basis.jl
@@ -71,7 +71,7 @@ function sp_T_matrix(ns, ls; mask=trues(length(ns),length(ns)), μω_gen=1.0, μ
     return (μω_gen / μ) .* mat
 end
 
-function sp_V_matrix(V_l, ns, ls; mask=trues(length(ns),length(ns)), dtype=Float64, cache=fill(NaN, 1+maximum(ls), 1+maximum(ns), 1+maximum(ns)))
+function sp_V_matrix(V_l, ns, ls; mask=trues(length(ns),length(ns)), dtype=Float64, cache=fill(convert(dtype, NaN), 1+maximum(ls), 1+maximum(ns), 1+maximum(ns)))
     mat = zeros(dtype, length(ns), length(ns))
     Threads.@threads for idx in CartesianIndices(mat) 
         if !mask[idx]; continue; end