Remove redundant tests and fix signed zero handling when window is sliding

kgryte · kgryte · commit 55915e5ddbec · 2018-05-14T12:39:50.000-07:00
diff --git a/lib/node_modules/@stdlib/stats/incr/mmax/lib/main.js b/lib/node_modules/@stdlib/stats/incr/mmax/lib/main.js
@@ -106,8 +106,8 @@ function incrmmax( W ) {
 		else if ( isnan( x ) && isnan( buf[ i ] ) ) {
 			max = x;
 		}
-		// Case: incoming value is greater than current maximum value OR incoming value is equal to current maximum value which is zero...
-		else if ( x > max || ( x === max && isPositiveZero( x ) ) ) {
+		// Case: incoming value is greater than current maximum value...
+		else if ( x > max ) {
 			max = x;
 		}
 		// Case: outgoing value is the current maximum and the new value is less than the maximum, and, thus, we need to find a new maximum among the current values...
@@ -126,6 +126,22 @@ function incrmmax( W ) {
 				}
 			}
 		}
+		// Case: outgoing value is the current maximum, which is zero, and the new value is also zero, and, thus, we need to correctly handle signed zeros...
+		else if ( buf[ i ] === max && x === max && x === 0.0 ) {
+			if ( isPositiveZero( x ) ) {
+				max = x;
+			} else if ( isPositiveZero( buf[ i ] ) ) {
+				// Because the outgoing and incoming are different signs (+,-), we need to search the buffer to see if it contains a positive zero. If so, it becomes the new maximum value; otherwise, the maximum value is incoming value...
+				max = x;
+				for ( k = 0; k < W; k++ ) {
+					if ( k !== i && isPositiveZero( buf[ k ] ) ) {
+						max = buf[ k ];
+						break;
+					}
+				}
+			}
+			// Case: both the outgoing and incoming are both negative zero, so nothing changes
+		}
 		// Case: updating existing window; however, the maximum value does not change so nothing to do but update our buffer...
 
 		buf[ i ] = x;
diff --git a/lib/node_modules/@stdlib/stats/incr/mmax/test/test.js b/lib/node_modules/@stdlib/stats/incr/mmax/test/test.js
@@ -114,21 +114,25 @@ tape( 'if data has yet to be provided, the accumulator function returns `null`',
 	t.end();
 });
 
-tape( 'the accumulator function correctly handles signed zeros (initial window)', function test( t ) {
+tape( 'the accumulator function correctly handles signed zeros', function test( t ) {
+	var expected;
+	var data;
 	var acc;
 	var v;
+	var i;
 
 	acc = incrmmax( 3 );
 
-	v = acc( -0.0 );
-	t.equal( isNegativeZero( v ), true, 'returns expected value' );
-
-	v = acc( 0.0 );
-	t.equal( isPositiveZero( v ), true, 'returns expected value' );
-
-	v = acc( -0.0 );
-	t.equal( isPositiveZero( v ), true, 'returns expected value' );
-
+	data = [ -0.0, 0.0, -0.0, -0.0, -0.0, 0.0, -0.0, -0.0, -0.0, 0.0 ];
+	expected = [ -0.0, 0.0, 0.0, 0.0, -0.0, 0.0, 0.0, 0.0, -0.0, 0.0 ];
+	for ( i = 0; i < data.length; i++ ) {
+		v = acc( data[ i ] );
+		if ( isPositiveZero( expected[ i ] ) ) {
+			t.equal( isPositiveZero( v ), true, 'returns expected value' );
+		} else {
+			t.equal( isNegativeZero( v ), true, 'returns expected value' );
+		}
+	}
 	t.end();
 });
 
