我正在尝试通过使用优化和Fixnums来提高一个小二次求解器的速度。以下是我的代码:
1: (defun solve-x (d)
2: (declare (optimize (speed 3))
3: (type fixnum d))
4: (let ((x 1) (y 1))
5: (declare (type fixnum x y))
6: (loop while (/= (- (* x x) (* d y y)) 1) do
7: (if (> (- (* x x) (* d y y)) 1)
8: (incf y)
9: (incf x)))
10: (list x y)))
SBCL编译器似乎在正确优化第6行和第7行的代码时遇到了问题。我收到了很多类似这样的警告:
forced to do GENERIC-- (cost 10)
unable to do inline fixnum arithmetic (cost 2) because:
The first argument is a (INTEGER 1 21267647932558653957237540927630737409), not a FIXNUM.
The second argument is a (INTEGER
-98079714615416886892398913872502479823289163909206900736
98079714615416886871131265939943825866051622981576163327), not a FIXNUM.
The result is a (VALUES
(INTEGER
-98079714615416886871131265939943825866051622981576163326
98079714615416886913666561805061133780526704836837638145)
&OPTIONAL), not a (VALUES FIXNUM &REST T).
unable to do inline (signed-byte 64) arithmetic (cost 5) because:
The first argument is a (INTEGER 1 21267647932558653957237540927630737409), not a (SIGNED-BYTE
64).
The second argument is a (INTEGER
-98079714615416886892398913872502479823289163909206900736
98079714615416886871131265939943825866051622981576163327), not a (SIGNED-BYTE
64).
The result is a (VALUES
(INTEGER
-98079714615416886871131265939943825866051622981576163326
98079714615416886913666561805061133780526704836837638145)
&OPTIONAL), not a (VALUES (SIGNED-BYTE 64) &REST T).
etc.
不知道该从哪里继续。我已经尝试在乘法、除法和减法周围插入“the fixnum”,但情况只会变得更糟。
有什么办法可以让这个更快吗?