use readdlm instead of read_file

Author: warisa-r

src/auxiliary/auxiliary.jl

@@ -346,20 +346,6 @@ function register_error_hints()
     return nothing
 end
 
-function read_file(file_path::AbstractString, data_type::Type = Float64)
-    @assert isfile(file_path) "Couldn't find file"
-    data = zeros(data_type, 0)
-    open(file_path, "r") do file
-        while !eof(file)
-            line_content = readline(file)
-            append!(data, parse(data_type, line_content))
-        end
-    end
-    num_lines = length(data)
-
-    return num_lines, data
-end
-
 """
     Trixi.download(src_url, file_path)
 

src/time_integration/paired_explicit_runge_kutta/methods_PERK2.jl

@@ -2,6 +2,8 @@
 # Since these FMAs can increase the performance of many numerical algorithms,
 # we need to opt-in explicitly.
 # See https://ranocha.de/blog/Optimizing_EC_Trixi for further details.
+using DelimitedFiles
+
 @muladd begin
 #! format: noindent
 
@@ -78,7 +80,10 @@ function compute_PERK2_butcher_tableau(num_stages, base_path_mon_coeffs::Abstrac
     a_matrix[:, 1] = c[3:end]
 
     path_mon_coeffs = base_path_mon_coeffs * "gamma_" * string(num_stages) * ".txt"
-    num_mon_coeffs, mon_coeffs = read_file(path_mon_coeffs, Float64)
+    @assert isfile(path_mon_coeffs) "Couldn't find file"
+    mon_coeffs = readdlm(path_mon_coeffs, Float64)
+    num_mon_coeffs = size(mon_coeffs, 1)
+
     @assert num_mon_coeffs == coeffs_max
     A = compute_a_coeffs(num_stages, bc_factors, mon_coeffs)
 
@@ -281,7 +286,7 @@ function solve!(integrator::PERK2Integrator)
             end
 
             # Higher stages
-            for stage in 3:alg.num_stages
+            for stage in 3:(alg.num_stages)
                 # Construct current state
                 @threaded for i in eachindex(integrator.du)
                     integrator.u_tmp[i] = integrator.u[i] +