optimized covariance script;

added 'nan' output to diff;
added ':' output delimiter to lin_reg and quad_reg;
fixed broken r^2 calc in quad_reg;

1 files changed, 1 insertions, 1 deletions

diff --git a/diff.awk b/diff.awk
index 721aac6..d39b654 100644
--- a/diff.awk
+++ b/diff.awk
@@ -55,7 +55,7 @@ NF {
             continue
         if ($y ~ number) {
             data[y] = $y
-            (data_prev[y] ~ number) ? diff[y] = data[y] - data_prev[y] : diff[y] = ""
+            (data_prev[y] ~ number) ? diff[y] = data[y] - data_prev[y] : diff[y] = "nan"
             data_prev[y] = data[y]
             printf(OFMT, diff[y])
         }