ImgMath: fix critical error in VarargsFunction: when the length of the array

was 2, the first operation was being duplicated.
While this wouldn't be an issue in java, it shows in scripting languages
that fail to use the 2-arg constructor and instead use the varags one.

Author: acardona

src/main/java/net/imglib2/algorithm/math/Add.java

@@ -26,8 +26,10 @@ public < O extends RealType< O > > Addition< O > reInit(
 			final O tmp,
 			final Map< String, O > bindings,
 			final Converter< RealType< ? >, O > converter,
-			Map< Variable< O >, OFunction< O > > imgSources )
+			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new Addition< O >( tmp.copy(), this.a.reInit( tmp, bindings, converter, imgSources ), this.b.reInit( tmp, bindings, converter, imgSources ) );
+		return new Addition< O >( tmp.copy(),
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }

src/main/java/net/imglib2/algorithm/math/Compute.java

@@ -79,15 +79,15 @@ public final void convert( final RealType< ? > input, final O output)
 					output.setReal( input.getRealDouble() );
 				}
 			};
-		
+			
 		// Recursive copy: initializes interval iterators and sets temporary computation holder
 		final OFunction< O > f = this.operation.reInit(
 				target.randomAccess().get().createVariable(),
 				new HashMap< String, O >(),
 				converter, null );
 
 		// Check compatible iteration order and dimensions
-		if ( compatible_iteration_order )
+		if ( this.compatible_iteration_order )
 		{
 			// Evaluate function for every pixel
 			for ( final O output : Views.iterable( target ) )

src/main/java/net/imglib2/algorithm/math/Div.java

@@ -27,8 +27,10 @@ public < O extends RealType< O > > Division< O > reInit(
 			final O tmp,
 			final Map< String, O > bindings,
 			final Converter< RealType< ? >, O > converter,
-			Map< Variable< O >, OFunction< O > > imgSources )
+			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new Division< O >( tmp.copy(), this.a.reInit( tmp, bindings, converter, imgSources ), this.b.reInit( tmp, bindings, converter, imgSources ) );
+		return new Division< O >( tmp.copy(),
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }

src/main/java/net/imglib2/algorithm/math/Equal.java

@@ -23,6 +23,8 @@ public < O extends RealType< O > > OFunction< O > reInit(
 			final Converter< RealType< ? >, O > converter,
 			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new Equality< O >( tmp.copy(), this.a.reInit( tmp, bindings, converter, imgSources ), this.b.reInit( tmp, bindings, converter, imgSources ) );
+		return new Equality< O >( tmp.copy(),
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }

src/main/java/net/imglib2/algorithm/math/GreaterThan.java

@@ -21,8 +21,10 @@ public < O extends RealType< O > > IsGreaterThan< O > reInit(
 			final O tmp,
 			final Map< String, O > bindings,
 			final Converter< RealType< ? >, O > converter,
-			Map< Variable< O >, OFunction< O > > imgSources )
+			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new IsGreaterThan< O >( tmp.copy(), this.a.reInit( tmp, bindings, converter, imgSources ), this.b.reInit( tmp, bindings, converter, imgSources ) );
+		return new IsGreaterThan< O >( tmp.copy(),
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }

src/main/java/net/imglib2/algorithm/math/ImgSource.java

@@ -29,7 +29,9 @@ public < O extends RealType< O > > OFunction< O > reInit(
 			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
 		// Optimization: if input image type is the same or a subclass of
-		// the output image type (represented here by tmp), then avoid the converter.
+		// the output image type (represented here by tmp), then avoid the converter
+		// but only if the targetImg is different than this.rai: otherwise, an intermediate
+		// computation result holder must be used (the scrap).
 		final OFunction< O > s;
 		if ( tmp.getClass().isAssignableFrom( this.rai.randomAccess().get().getClass() ) )
 			s = new ImgSourceIterableDirect< O >( ( RandomAccessibleInterval< O > )this.rai );

src/main/java/net/imglib2/algorithm/math/LessThan.java

@@ -23,6 +23,8 @@ public < O extends RealType< O > > IsLessThan< O > reInit(
 			final Converter< RealType< ? >, O > converter,
 			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new IsLessThan< O >( tmp.copy(), this.a.reInit( tmp, bindings, converter, imgSources ), this.b.reInit( tmp, bindings, converter, imgSources ) );
+		return new IsLessThan< O >( tmp.copy(),
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }

src/main/java/net/imglib2/algorithm/math/Let.java

@@ -68,7 +68,9 @@ public < O extends RealType< O > > LetBinding< O > reInit(
 		final O scrap = tmp.copy();
 		final Map< String, O > rebind = new HashMap<>( bindings );
 		rebind.put( this.varName, scrap );
-		return new LetBinding< O >( scrap, this.varName, this.varValue.reInit( tmp, rebind, converter, imgSources ), this.body.reInit( tmp, rebind, converter, imgSources ) );
+		return new LetBinding< O >( scrap, this.varName,
+				this.varValue.reInit( tmp, rebind, converter, imgSources ),
+				this.body.reInit( tmp, rebind, converter, imgSources ) );
 	}
 
 	@Override

src/main/java/net/imglib2/algorithm/math/Max.java

@@ -28,6 +28,8 @@ public < O extends RealType< O > > Maximum< O > reInit(
 			final Converter< RealType< ? >, O > converter,
 			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new Maximum< O >( this.a.reInit( tmp, bindings, converter, imgSources ), this.b.reInit( tmp, bindings, converter, imgSources ) );
+		return new Maximum< O >(
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }

src/main/java/net/imglib2/algorithm/math/Min.java

@@ -28,6 +28,8 @@ public < O extends RealType< O > > Minimum< O > reInit(
 			final Converter< RealType< ? >, O > converter,
 			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new Minimum< O >( this.a.reInit(tmp, bindings, converter, imgSources), this.b.reInit(tmp, bindings, converter, imgSources) );
+		return new Minimum< O >(
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }