max threads to 48

src/population.rs

@@ -81,7 +81,7 @@ impl Population {
         let mut stats: [i32; 4] = [0, 0, 0, 0];
 
         let num_threads = num_threads.unwrap_or(1);
-        if num_threads > 8 {
+        if num_threads > 48 {
             panic!("too many threads")
         }