t*e
2 楼
我看到满多雌花的,下面有小小的黄瓜,可是到话都掉了,黄瓜还是那么个大,就像小
指头那么点
这是什么原因呢
指头那么点
这是什么原因呢
d*t
3 楼
为啥一堆人膜拜
y*o
4 楼
Tailoring the Metallocene Structure To Obtain LLDPE by Ethene
Homopolymerization: An Experimental and Theoretical Study
Organometallics, 2008, 27 (7), pp 1367–1371
DOI: 10.1021/om7006562
http://pubs.acs.org/doi/abs/10.1021/om7006562
Branched Polyethylene by Ethylene Homopolymerization with meso-Zirconocene
Catalyst
Macromolecules, 1999, 32 (21), pp 6913–6916
DOI: 10.1021/ma9905876
http://pubs.acs.org/doi/abs/10.1021/ma9905876
Formation of Quaternary Carbon Centers in Ethylene Polymerization with meso-
Isopropylidenebis(1-indenyl)zirconium Dichloride Activated by MAO
Macromolecules, 2001, 34 (1), pp 2–4
DOI: 10.1021/ma0015119
http://pubs.acs.org/doi/abs/10.1021/ma0015119
多谢了!
Homopolymerization: An Experimental and Theoretical Study
Organometallics, 2008, 27 (7), pp 1367–1371
DOI: 10.1021/om7006562
http://pubs.acs.org/doi/abs/10.1021/om7006562
Branched Polyethylene by Ethylene Homopolymerization with meso-Zirconocene
Catalyst
Macromolecules, 1999, 32 (21), pp 6913–6916
DOI: 10.1021/ma9905876
http://pubs.acs.org/doi/abs/10.1021/ma9905876
Formation of Quaternary Carbon Centers in Ethylene Polymerization with meso-
Isopropylidenebis(1-indenyl)zirconium Dichloride Activated by MAO
Macromolecules, 2001, 34 (1), pp 2–4
DOI: 10.1021/ma0015119
http://pubs.acs.org/doi/abs/10.1021/ma0015119
多谢了!
m*h
5 楼
是啊,我也试了很久了。不知道什么时候才能好啊。
w*w
6 楼
蓝绿失衡,需要招蜂引蝶。
c*o
7 楼
基本上,正规化,用的人多
i*g
9 楼
still down
i*e
10 楼
赶紧人工授粉吧
z*e
11 楼
ide
jvm
jvm
y*o
12 楼
非常感谢您的帮助。
d*x
13 楼
keep trying...
d*x
19 楼
是在不行明天让老妈自己去中信买了。虽然他们会觉得很麻烦。
K*A
20 楼
据我这初级农民的操作,每株留俩到三根小小黄瓜,其余都掐掉。顶太高了也要掐。我
倒是从来不授粉的。
倒是从来不授粉的。
c*o
21 楼
版上有人争论c++怎么写,有人争论java么
java人最多
java人最多
n*7
27 楼
一个做software programming,一个是脚本
连我们杀老鼠的都要求c/c++/java 必须熟悉一个
然后perl/python会一个
连我们杀老鼠的都要求c/c++/java 必须熟悉一个
然后perl/python会一个
w*w
38 楼
factory pattern 应该是很简单的pattern当中的一种了。 要搞清楚 visitor pattern
的应用场合才算对pattern 理解上升一个高度。 其实pattern 在我眼里面看来核心就
是封装, 哪里有变化,哪里就有封装!这个才是pattern的核心思想。factory
pattern 这样的构造的pattern , 个人看来是很基本的pattern。 到了后来我感觉有
的时候 pattern 都是拉花架子,总是搞个中间类在哪里适应变化, 层层叠绕的。大多
数的时候 用functor 加上boost 里面的bind 足够了。直接应用装配,不用啥包这个
class 那个class的。想咋装配就咋装配! 更加灵活一点。 个人意见, 望少拍砖! ^
_^
的应用场合才算对pattern 理解上升一个高度。 其实pattern 在我眼里面看来核心就
是封装, 哪里有变化,哪里就有封装!这个才是pattern的核心思想。factory
pattern 这样的构造的pattern , 个人看来是很基本的pattern。 到了后来我感觉有
的时候 pattern 都是拉花架子,总是搞个中间类在哪里适应变化, 层层叠绕的。大多
数的时候 用functor 加上boost 里面的bind 足够了。直接应用装配,不用啥包这个
class 那个class的。想咋装配就咋装配! 更加灵活一点。 个人意见, 望少拍砖! ^
_^
d*i
39 楼
实际上plain old pure C的速度是最快的,这一点是毫无争议的,而且即便是和手写的
asm比,C也往往更快,编译器的优化已经可以做的极致,即便是在性能要求苛刻的不能
再苛刻的embedded上面,一般也不提倡手写asm, 只有一些极少数特殊的场合采用。C++
比C在ARM Linux上纯速度大概是1.2比1的样子,主要耗费在类的construct上面了和
virtual table上面了。Java则无可比性,大概差个3-5倍,不过在server上这个比例一
般不是问题。
【在 c******o 的大作中提到】
: 高频是因为GC stop the world?不是速度吧?
: 当然, bare metal是不一样,C/C++除了assembly 无人可比
asm比,C也往往更快,编译器的优化已经可以做的极致,即便是在性能要求苛刻的不能
再苛刻的embedded上面,一般也不提倡手写asm, 只有一些极少数特殊的场合采用。C++
比C在ARM Linux上纯速度大概是1.2比1的样子,主要耗费在类的construct上面了和
virtual table上面了。Java则无可比性,大概差个3-5倍,不过在server上这个比例一
般不是问题。
【在 c******o 的大作中提到】
: 高频是因为GC stop the world?不是速度吧?
: 当然, bare metal是不一样,C/C++除了assembly 无人可比
n*l
44 楼
it is cute to do that cheating, but a more straightforward way in c
is to construct a lookup table, which is O(1) and can be more
flexible at runtime than c++ template metaprogramming if such need
rises.
【在 b*******s 的大作中提到】
: a classic example, calculate fibonacci(10000) please.
: modern c++ can finish it in O(1)
is to construct a lookup table, which is O(1) and can be more
flexible at runtime than c++ template metaprogramming if such need
rises.
【在 b*******s 的大作中提到】
: a classic example, calculate fibonacci(10000) please.
: modern c++ can finish it in O(1)
d*i
45 楼
Or more precisely, when you program in C and C++, you actually want to have
full control of memory management by YOU as a programmer rather than
automatically managed by GC.
【在 d****i 的大作中提到】
: garbage collection, not allowed by C and C++ since they are system level
: languages thus cannot afford any bit of performance loss.
full control of memory management by YOU as a programmer rather than
automatically managed by GC.
【在 d****i 的大作中提到】
: garbage collection, not allowed by C and C++ since they are system level
: languages thus cannot afford any bit of performance loss.
b*s
47 楼
do you understand the downside of your solution?
if I want some values between F(1) and F(10000)
you should keep a large lookup table. and it is not cache friendly
the best idea from c++ is: you dont use, you dont pay for it
【在 n****l 的大作中提到】
: it is cute to do that cheating, but a more straightforward way in c
: is to construct a lookup table, which is O(1) and can be more
: flexible at runtime than c++ template metaprogramming if such need
: rises.
if I want some values between F(1) and F(10000)
you should keep a large lookup table. and it is not cache friendly
the best idea from c++ is: you dont use, you dont pay for it
【在 n****l 的大作中提到】
: it is cute to do that cheating, but a more straightforward way in c
: is to construct a lookup table, which is O(1) and can be more
: flexible at runtime than c++ template metaprogramming if such need
: rises.
n*l
49 楼
i never thought modern c++ bloat is cache friendly to begin with.
so how is your c++ version solving this precise issue if it can even solve
it at all dynamically at runtime?
【在 b*******s 的大作中提到】
: do you understand the downside of your solution?
: if I want some values between F(1) and F(10000)
: you should keep a large lookup table. and it is not cache friendly
: the best idea from c++ is: you dont use, you dont pay for it
so how is your c++ version solving this precise issue if it can even solve
it at all dynamically at runtime?
【在 b*******s 的大作中提到】
: do you understand the downside of your solution?
: if I want some values between F(1) and F(10000)
: you should keep a large lookup table. and it is not cache friendly
: the best idea from c++ is: you dont use, you dont pay for it
d*i
50 楼
Smart pointer isn't GC at all. For the code I have ever encountered, smart
pointers in C++ are used sparsely particularly on server side . But for
other use cases such as embedded system, Android, iOS, RTOS,... whatsoever,
they are never used.
【在 b*******s 的大作中提到】
: c++ now has light weight gc. or said smart pointers
: auto release is no longer a problem
pointers in C++ are used sparsely particularly on server side . But for
other use cases such as embedded system, Android, iOS, RTOS,... whatsoever,
they are never used.
【在 b*******s 的大作中提到】
: c++ now has light weight gc. or said smart pointers
: auto release is no longer a problem
b*s
51 楼
Okay I will give you an example. Suppose you have already known something
about meta programming.
If I want to use F(1) F(1000) and F(10000) in my application. Maybe like
this,
constexpr int64_t val = F(1) + F(1000) + F(10000);
Do you think there any cache issue? No, obviously
And F(1) F(1000) F(10000) are in different cache lines in your solution.
Or you should design a complicated hash function.
We don't like runtime things. That's modern c++
【在 n****l 的大作中提到】
: i never thought modern c++ bloat is cache friendly to begin with.
: so how is your c++ version solving this precise issue if it can even solve
: it at all dynamically at runtime?
about meta programming.
If I want to use F(1) F(1000) and F(10000) in my application. Maybe like
this,
constexpr int64_t val = F(1) + F(1000) + F(10000);
Do you think there any cache issue? No, obviously
And F(1) F(1000) F(10000) are in different cache lines in your solution.
Or you should design a complicated hash function.
We don't like runtime things. That's modern c++
【在 n****l 的大作中提到】
: i never thought modern c++ bloat is cache friendly to begin with.
: so how is your c++ version solving this precise issue if it can even solve
: it at all dynamically at runtime?
b*s
53 楼
and we cant avoid some silly context switching with Java. another reason we
don't like it. it is a so expensive penalty.
All silly "c++ vs java" benchmarks are single threaded and written by Java
programmers. LOL
don't like it. it is a so expensive penalty.
All silly "c++ vs java" benchmarks are single threaded and written by Java
programmers. LOL
w*w
54 楼
高频交易主要focus 在 low latency。不是说大并发就是高频,追求的是反应时间。在
追求这个latency 的问题上,有os 都闲慢,更别说啥语言不语言了。像啥JMS 这样的
message传送机制,在高频交易当中就可以当作个笑话了。追求low latency吗? 硬件
直接来!你软件再怎么快也跟硬件还是查一个数量级吧? os 怎么也要从kernel 到
user space的转换, 这个时间人家都省下来了。
追求这个latency 的问题上,有os 都闲慢,更别说啥语言不语言了。像啥JMS 这样的
message传送机制,在高频交易当中就可以当作个笑话了。追求low latency吗? 硬件
直接来!你软件再怎么快也跟硬件还是查一个数量级吧? os 怎么也要从kernel 到
user space的转换, 这个时间人家都省下来了。
b*g
55 楼
所以这就叫井底观天,Java不适合实时应用是事实,C++还不适合网络应用呢。总有傻
逼做个高频就觉得天就这么大了, Java是笑话,哪怕最基本的数据库概念都没有。
【在 w******w 的大作中提到】
: 高频交易主要focus 在 low latency。不是说大并发就是高频,追求的是反应时间。在
: 追求这个latency 的问题上,有os 都闲慢,更别说啥语言不语言了。像啥JMS 这样的
: message传送机制,在高频交易当中就可以当作个笑话了。追求low latency吗? 硬件
: 直接来!你软件再怎么快也跟硬件还是查一个数量级吧? os 怎么也要从kernel 到
: user space的转换, 这个时间人家都省下来了。
逼做个高频就觉得天就这么大了, Java是笑话,哪怕最基本的数据库概念都没有。
【在 w******w 的大作中提到】
: 高频交易主要focus 在 low latency。不是说大并发就是高频,追求的是反应时间。在
: 追求这个latency 的问题上,有os 都闲慢,更别说啥语言不语言了。像啥JMS 这样的
: message传送机制,在高频交易当中就可以当作个笑话了。追求low latency吗? 硬件
: 直接来!你软件再怎么快也跟硬件还是查一个数量级吧? os 怎么也要从kernel 到
: user space的转换, 这个时间人家都省下来了。
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