deriva3.java

Expression expr = sin(mul(sq('x'), sq('y')));
Vector1D g_expr = vector(expr, d(expr, 'x'), d(expr, 'x'));
System.out.println(g_expr.describe());

Expression:
[(sin (* (sq x) (sq y)))
 (d (sin (* (sq x) (sq y))) x)
 (d (sin (* (sq x) (sq y))) x)]

gets turned into:
(vector
 (sin (* (sq x) (sq y)))
 (* (cos (* (sq x) (sq y))) (* (* 2 x) (sq y)))
 (* (cos (* (sq x) (sq y))) (* (* 2 x) (sq y))))

 and into:
final double G__1343 = y;  //  y
final double G__1342 = sq( G__1343 );  //  (sq y)
final double G__1341 = x;  //  x
final double G__1340 = 2;  //  2
final double G__1339 = G__1340 * G__1341;  //  (* 2 x)
final double G__1338 = G__1339 * G__1342;  //  (* (* 2 x) (sq y))
final double G__1334 = sq( G__1341 );  //  (sq x)
final double G__1333 = G__1334 * G__1342;  //  (mul (sq x) (sq y))
final double G__1332 = cos( G__1333 );  //  (cos (mul (sq x) (sq y)))
final double G__1331 = G__1332 * G__1338;  //  (* (cos (mul (sq x) (sq y))) (* (* 2 x) (sq y)))
final double G__1312 = sin( G__1333 );  //  (sin (mul (sq x) (sq y)))
final double G__1311 = [ G__1312, G__1331, G__1331 ];  //  (vector (sin (mul (sq x) (sq y))) (* (cos (mul (sq x) (sq y))) (* (* 2 x) (sq y))) (* (cos (mul (sq x) (sq y))) (* (* 2 x) (sq y))))