更新:在我的内核int4
是错误的。与PyOpenCL结构对齐
我正在使用pyopencl,但无法使结构对齐正常工作。在下面调用内核两次的代码中,b
值正确返回(如1),但c
值有一些“随机”值。
换句话说:我想读一个结构的两个成员。我可以阅读第一个,但不是第二个。为什么?
无论我使用numpy结构化数组还是使用struct打包,都会发生同样的问题。并且评论中的_-attribute__
设置也没有帮助。
我怀疑我在代码的其他地方做了些愚蠢的事,但看不到它。任何帮助赞赏。
import struct as s
import pyopencl as cl
import numpy as n
ctx = cl.create_some_context()
queue = cl.CommandQueue(ctx)
for use_struct in (True, False):
if use_struct:
a = s.pack('=ii',1,2)
print(a, len(a))
a_dev = cl.Buffer(ctx, cl.mem_flags.WRITE_ONLY, len(a))
else:
# a = n.array([(1,2)], dtype=n.dtype('2i4', align=True))
a = n.array([(1,2)], dtype=n.dtype('2i4'))
print(a, a.itemsize, a.nbytes)
a_dev = cl.Buffer(ctx, cl.mem_flags.WRITE_ONLY, a.nbytes)
b = n.array([0], dtype='i4')
print(b, b.itemsize, b.nbytes)
b_dev = cl.Buffer(ctx, cl.mem_flags.READ_ONLY, b.nbytes)
c = n.array([0], dtype='i4')
print(c, c.itemsize, c.nbytes)
c_dev = cl.Buffer(ctx, cl.mem_flags.READ_ONLY, c.nbytes)
prg = cl.Program(ctx, """
typedef struct s {
int4 f0;
int4 f1 __attribute__ ((packed));
// int4 f1 __attribute__ ((aligned (4)));
// int4 f1;
} s;
__kernel void test(__global const s *a, __global int4 *b, __global int4 *c) {
*b = a->f0;
*c = a->f1;
}
""").build()
cl.enqueue_copy(queue, a_dev, a)
event = prg.test(queue, (1,), None, a_dev, b_dev, c_dev)
event.wait()
cl.enqueue_copy(queue, b, b_dev)
print(b)
cl.enqueue_copy(queue, c, c_dev)
print(c)
输出(我不得不重新格式化,同时切+粘贴,所以可能会搞砸线略微突破;我还添加了评论,指出各种打印值):
# first using struct
/home/andrew/projects/personal/kultrung/env/bin/python3.2 /home/andrew/projects/personal/kultrung/src/kultrung/test6.py
b'\x01\x00\x00\x00\x02\x00\x00\x00' 8 # the struct packed values
[0] 4 4 # output buffer 1
[0] 4 4 # output buffer 2
/home/andrew/projects/personal/kultrung/env/lib/python3.2/site-packages/pyopencl/cache.py:343: UserWarning: Build succeeded, but resulted in non-empty logs: Build on <pyopencl.Device 'Intel(R) Core(TM)2 CPU T5600 @ 1.83GHz' at 0x1385a20> succeeded, but said:
Build started Kernel <test> was successfully vectorized Done. warn("Build succeeded, but resulted in non-empty logs:\n"+message)
[1] # the first value (correct)
[240] # the second value (wrong)
# next using numpy
[[1 2]] 4 8 # the numpy struct
[0] 4 4 # output buffer
[0] 4 4 # output buffer
/home/andrew/projects/personal/kultrung/env/lib/python3.2/site-packages/pyopencl/__init__.py:174: UserWarning: Build succeeded, but resulted in non-empty logs: Build on <pyopencl.Device 'Intel(R) Core(TM)2 CPU T5600 @ 1.83GHz' at 0x1385a20> succeeded, but said:
Build started Kernel <test> was successfully vectorized Done. warn("Build succeeded, but resulted in non-empty logs:\n"+message)
[1] # first value (ok)
[67447488] # second value (wrong)
Process finished with exit code 0
谢谢,我只是试了一下,但它没有解决问题(也是在这里“包装”下的第一个例子http://www.khronos.org/registry/cl/sdk/1.0/docs/man/ xhtml/attributes-variables.html表明它应该是我拥有它的地方,我认为) –