ImgMath fixes

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/ImgMath.java

@@ -232,4 +232,14 @@ static public final Else ELSE( final Object o )
 	{
 		return new Else( o );
 	}
+
+	static public final < T extends RealType< T > > ImgSource< T > img( final RandomAccessibleInterval< T > rai )
+	{
+		return new ImgSource< T >( rai );
+	}
+
+	static public final NumberSource number( final Number number )
+	{
+		return new NumberSource( number );
+	}
 }

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 ) );
 	}
 }

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

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

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

@@ -22,6 +22,8 @@ public < O extends RealType< O > > NotEquality< O > reInit(
 			final Converter< RealType< ? >, O > converter,
 			final Map< Variable< O >, OFunction< O > > imgSources )
 	{
-		return new NotEquality< O >( tmp.copy(), this.a.reInit( tmp, bindings, converter, imgSources ), this.b.reInit( tmp, bindings, converter, imgSources ) );
+		return new NotEquality< O >( tmp.copy(),
+				this.a.reInit( tmp, bindings, converter, imgSources ),
+				this.b.reInit( tmp, bindings, converter, imgSources ) );
 	}
 }

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

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

src/main/java/net/imglib2/algorithm/math/abstractions/AUnaryFunction.java

@@ -2,7 +2,7 @@
 
 import net.imglib2.type.numeric.RealType;
 
-abstract public class AUnaryFunction extends VarargsFunction implements IUnaryFunction
+abstract public class AUnaryFunction implements IUnaryFunction
 {
 	protected final IFunction a;
 

src/main/java/net/imglib2/algorithm/math/abstractions/VarargsFunction.java

@@ -5,8 +5,11 @@
 abstract public class VarargsFunction
 {
 	final public IFunction[] wrapMap( final Object[] obs )
-	{	
+	{
 		try {
+			if ( 2 == obs.length )
+				return new IFunction[]{ Util.wrap( obs[ 0 ] ), Util.wrap( obs[ 1 ]) };
+
 			final Constructor< ? > constructor = this.getClass().getConstructor( new Class[]{ Object.class, Object.class } );
 			ABinaryFunction a = ( ABinaryFunction )constructor.newInstance( obs[0], obs[1] );
 			ABinaryFunction b;