使用g ++版本4.7.2,如果我尝试编译以下内容
#include <boost/date_time/local_time/local_time.hpp>
class Bar
{
public:
Bar() { tz_db_.load_from_file("/home/date_time_zonespec.csv"); }
private:
boost::local_time::tz_database tz_db_;
};
int main()
{
return 0;
}
使用-std = c ++ 0x我收到以下错误.
In file included from /usr/local/include/boost/date_time/local_time/local_time_types.hpp:18:0,
from /usr/local/include/boost/date_time/local_time/local_time.hpp:13,
from test.h:4,
from test.cpp:1: /usr/local/include/boost/date_time/local_time/custom_time_zone.hpp: In instantiation of ‘bool boost::local_time::custom_time_zone_base<CharT>::has_dst() const [with CharT = char]’: test.cpp:11:1: required from here /usr/local/include/boost/date_time/local_time/custom_time_zone.hpp:67:30: error: cannot convert ‘const boost::shared_ptr<boost::date_time::dst_day_calc_rule<boost::gregorian::date>
>’ to ‘bool’ in return
如果我不使用c ++ 0x选项,一切都很好.谁能告诉我这里发生了什么？
我有一个看起来像这样的数据框
A B C
1 3 X1=7;X2=8;X3=9
2 4 X1=10;X2=11;X3=12
5 6 X1=13;X2=14
我想将C列解析为单独的列...
A B X1 X2 X3
1 3 7 8 9
2 4 10 11 12
5 6 13 14 NA
怎么会在R中这样做呢？
我无法理解为什么以下代码无法编译.
#include <memory>
#include <functional>
class Foo
{
public:
void Bar(int i) {}
};
void X(std::function<void(std::shared_ptr<Foo>)> f)
{
}
int main()
{
std::shared_ptr<Foo> f(new Foo);
auto f1(std::bind(&Foo::Bar, std::placeholders::_1, 1));
X(f1);
return 0;
}
g ++(4.6.3)输出......
n file included from /usr/include/c++/4.6/memory:80:0,
from test.cpp:1:
/usr/include/c++/4.6/functional: In static member function ‘static void std::_Function_handler<void(_ArgTypes ...), _Functor>::_M_invoke(const std::_Any_data&, _ArgTypes ...) [with _Functor = std::_Bind<std::_Mem_fn<void (Foo::*)(int)>(std::_Placeholder<1>, int)>, _ArgTypes = {std::shared_ptr<Foo>}]’:
/usr/include/c++/4.6/functional:2148:6: instantiated from ‘std::function<_Res(_ArgTypes ...)>::function(_Functor, typename std::enable_if<(! std::is_integral<_Functor>::value), std::function<_Res(_ArgTypes ...)>::_Useless>::type) [with _Functor = std::_Bind<std::_Mem_fn<void (Foo::*)(int)>(std::_Placeholder<1>, int)>, …我以前曾经问过,但我找不到确切的答案.如果我有一个数字表示自午夜以来的毫秒数,比如34200577,我该如何将其转换为R时间？
我们在视频会议项目中使用x264编码器，我们具有基本的流视频功能，但是，在理解各种速率控制设置如何确定最终比特率时遇到了麻烦。我们设置以下参数：
x264_param_t params;
x264_param_default_preset(¶ms, "ultrafast", "zerolatency");
params.i_threads = 1;
params.i_width = width;
params.i_height = height;
params.i_fps_num = fps;
params.i_keyint_max = fps;
params.b_intra_refresh = 1;
params.b_repeat_headers = 1;
params.b_annexb = 1;
//Set rate control stuff here
x264_param_apply_profile(¶ms, "baseline");
如果仅设置params.rc.i_bitrate参数，则编码器似乎会严重超出比特率。如果我们设置i_vbv_max_bitrate和i_vbv_buffer_size参数，我们将看到一个比特率达到i_vbv_max_bitrate设置的峰值（有时过冲）。显然，严格控制比特币对视频会议很重要，但是文档是不透明的。还有其他人使用x264进行视频会议吗？您如何设置编码器？任何帮助表示赞赏，在此先感谢。
可以通过total_microseconds方法从time_duration获得微秒的总数,但我无法弄清楚如何从该数字重新构造time_duration.在文档中似乎没有用于此目的的构造函数,我错过了什么吗？
我有一系列向量,我将其添加到DataFrame对象中以返回R.当我尝试添加具有长long元素的向量时出现问题.
// [[Rcpp::export]]
DataFrame test()
{
std::vector<long long> x;
return DataFrame::create(Named("x") = x);
}
返回的错误是
g ++ -m64 -I"C:/R/R-30~1.1/include"-DNDEBUG -I"C:/R/R-3.0.1/library/Rcpp/include"-I"d:/ RCompile/CRANpkg/extralibs64/local/include"-O2 -Wall -mtune = core2 -c quotes.cpp -o quotes.o在C:/R/R-3.0.1/library/Rcpp/include/RcppCommon.h中包含的文件中: 117:0,来自C:/ R/R-3.0.1/library/Rcpp/include/Rcpp.h:27,来自quotes.cpp:1:C:/R/R-3.0.1/library/Rcpp/ include/Rcpp/internal/wrap.h:函数'SEXPREC*Rcpp :: internal :: wrap_dispatch_unknown_iterable(const T&,Rcpp :: traits :: false_type)[T = long long int,SEXP = SEXPREC*,Rcpp :: traits :: false_type = Rcpp :: traits :: integral_constant]':C:/ R/R-3.0.1/library/Rcpp/include/Rcpp/internal/wrap.h:691:98:从'SEXPREC*Rcpp实例化:: internal :: wrap_dispatch_unknown(const T&,Rcpp :: traits ::false_type)[T = long long int,SEXP = SEXPREC*,Rcpp :: traits :: false_type = Rcpp :: traits :: …