Indices: ice_differential: Refactor ($n_infreq - 1)

This is re-used many times in the calculations
shawnlaffan · Feb 19, 2024 · 0f84deb · 0f84deb
1 parent 8e77c16
commit 0f84deb
Showing 1 changed file with 12 additions and 11 deletions.
diff --git a/lib/Biodiverse/Indices/RichnessEstimation.pm b/lib/Biodiverse/Indices/RichnessEstimation.pm
@@ -773,6 +773,7 @@ sub _get_ice_differential {
     my $t_1 = $t - 1;  #  used many times below
 
     if ($CV_infreq_h != 0) {
+        my $n_infreq_1 = $n_infreq - 1;
         if ($q == 1) {
             $dc_infreq =
               -1 * (
@@ -783,17 +784,17 @@ sub _get_ice_differential {
 
             $d = ($C_infreq - $D_infreq * $dc_infreq) / $C_infreq ** 2
                 + $t / $t_1
-                  * ($C_infreq**2*$n_infreq*($n_infreq - 1)
+                  * ($C_infreq**2*$n_infreq*$n_infreq_1
                         * ($D_infreq * $si + $Q1 * $si)
                         - $Q1 * $D_infreq * $si *
                         (2 * $C_infreq * $dc_infreq
-                         * $n_infreq * ($n_infreq - 1)
+                         * $n_infreq * $n_infreq_1
                          + $C_infreq ** 2
-                         * ($n_infreq - 1)
+                         * $n_infreq_1
                          + $C_infreq ** 2
                          * $n_infreq
                          )
-                    ) / $C_infreq ** 4 / $n_infreq ** 2 / ($n_infreq - 1) ** 2
+                    ) / $C_infreq ** 4 / $n_infreq ** 2 / $n_infreq_1 ** 2
                 - ($C_infreq - $Q1 * $dc_infreq) / $C_infreq**2;
         }
         elsif ($q == 2){
@@ -807,10 +808,10 @@ sub _get_ice_differential {
             $d = ($C_infreq - $D_infreq * $dc_infreq)
                 / $C_infreq**2
               + $t / $t_1
-              * ($C_infreq**2 * $n_infreq * ($n_infreq - 1) * $Q1 * ($si + 2 * $D_infreq) - $Q1 * $D_infreq * $si *
-                             (2 * $C_infreq * $dc_infreq * $n_infreq * ($n_infreq - 1) + $C_infreq**2 * 2 * ($n_infreq - 1) + $C_infreq**2 * $n_infreq * 2)
+              * ($C_infreq**2 * $n_infreq * $n_infreq_1 * $Q1 * ($si + 2 * $D_infreq) - $Q1 * $D_infreq * $si *
+                             (2 * $C_infreq * $dc_infreq * $n_infreq * $n_infreq_1 + $C_infreq**2 * 2 * $n_infreq_1 + $C_infreq**2 * $n_infreq * 2)
                 )
-              / $C_infreq**4 / $n_infreq**2 / ($n_infreq - 1)**2
+              / $C_infreq**4 / $n_infreq**2 / $n_infreq_1**2
               - ( -$Q1 * $dc_infreq) / $C_infreq**2;
         }
         else {
@@ -820,13 +821,13 @@ sub _get_ice_differential {
 
             $d = ($C_infreq - $D_infreq * $dc_infreq) / $C_infreq**2
               + $t/$t_1
-              * ($C_infreq**2 * $n_infreq * ($n_infreq - 1) * $Q1 * ($si + $q * ($q - 1) * $D_infreq) - $Q1 * $D_infreq * $si
-                * (2 * $C_infreq * $dc_infreq * $n_infreq * ($n_infreq - 1)
-                   + $C_infreq**2 * $q * ($n_infreq - 1)
+              * ($C_infreq**2 * $n_infreq * $n_infreq_1 * $Q1 * ($si + $q * ($q - 1) * $D_infreq) - $Q1 * $D_infreq * $si
+                * (2 * $C_infreq * $dc_infreq * $n_infreq * $n_infreq_1
+                   + $C_infreq**2 * $q * $n_infreq_1
                    + $C_infreq**2 * $n_infreq * $q
                   )
               )
-              / $C_infreq**4 / $n_infreq**2 / ($n_infreq - 1)**2
+              / $C_infreq**4 / $n_infreq**2 / $n_infreq_1**2
               - ( - $Q1 * $dc_infreq) / $C_infreq**2;
         }
     }