X-Git-Url: http://git.shiar.nl/barcat.git/blobdiff_plain/13fb03e4b877662289ca3395ce81f7a8462b127a..dc97b2596fd2429ae31c4c4987127ff48d350a1e:/barcat

diff --git a/barcat b/barcat
index 08b3db2..1fd0dd3 100755
--- a/barcat
+++ b/barcat
@@ -400,11 +400,9 @@ sub show_stat {
 		$vars{partsum} = sum(0, grep {length} @values[$linemin .. $linemax])
 			if $linemin <= $linemax and ($opt{hidemin} or $opt{hidemax});
 		%vars = (%vars,
-			sum => sum(@order),
 			min => $order[-1],
 			max => $order[0],
 		);
-		$vars{avg} = $vars{sum} / @order;
 	}
 	say varfmt($opt{report}, \%vars);
 	return 1;
@@ -413,17 +411,29 @@ sub show_stat {
 sub calc {
 	my ($func) = @_;
 	if ($func eq 'avg') {
-		return sum(@order) / @order;
+		return calc('sum') / @order;
 	}
 	elsif ($func eq 'sum') {
-		return sum(@order);
+		state $cache;         # avoid recount
+		state $cachednr = 0;  # if unchanged
+		unless (@order == $cachednr) {
+			$cache = sum(@order);
+			$cachednr = @order;
+		}
+		return $cache;
 	}
 	elsif ($func =~ /\A([0-9.]+)v\z/) {
 		$1 <= 100 or die(
 			"percentile $1 out of bounds\n"
 		);
 		my $index = $#order * $1 / 100;
-		return ($order[$index] + $order[$index + .5]) / 2;
+		my $f = $index - int $index;
+		my $val = $order[$index];
+		if ($f) {
+			my $next = $order[$index + 1];
+			$val -= $f * ($val - $next);
+		}
+		return $val;
 	}
 	elsif ($func =~ /\A-?[0-9.]+\z/) {
 		return $func;
@@ -442,7 +452,7 @@ sub varfmt {
 		defined && do {
 			$_ = $opt{'value-format'}->($_) if $format;
 			if ($cmd and $op eq ':') {
-				$_ = varfmt($cmd, $vars);
+				$_ = !!$_ && varfmt($cmd, $vars);
 			}
 			elsif ($cmd) {
 				eval $cmd;
@@ -638,10 +648,13 @@ For example C<:/1> for a grid at every integer.
 
 =item I<percentage>B<v>
 
-Ranked value at the given percentile.
-The default shows C<+> at C<50v> for the mean or median;
-the middle value or average between middle values.
-One standard deviation right of the mean is at about C<68.3v>.
+Ranked value at the given percentile,
+or score at or below which a percentage falls
+in its frequency distribution (inclusive).
+
+The default shows C<+> at C<50v> for the mean or median:
+the middle value or interpolation between two values.
+One standard deviation below the median is at about C<68v>.
 The default includes C<< >31.73v <68.27v >>
 to encompass all I<normal> results, or 68% of all entries, by I<< <--> >>.