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C++ default_ops::eval_convert_to方法代码示例

本文整理汇总了C++中default_ops::eval_convert_to方法的典型用法代码示例。如果您正苦于以下问题:C++ default_ops::eval_convert_to方法的具体用法?C++ default_ops::eval_convert_to怎么用?C++ default_ops::eval_convert_to使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在default_ops的用法示例。


在下文中一共展示了default_ops::eval_convert_to方法的5个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。

示例1: eval_convert_to

inline void eval_convert_to(R* result, const logged_adaptor<Backend>& val)
{
   using default_ops::eval_convert_to;
   log_prefix_event(val.value(), "convert_to");
   eval_convert_to(result, val.value());
   log_postfix_event(val.value(), *result, "convert_to");
}
开发者ID:BackupTheBerlios,项目名称:airdc-svn,代码行数:7,代码来源:logged_adaptor.hpp

示例2: generic_interconvert

void generic_interconvert(To& to, const From& from, const mpl::int_<number_kind_integer>& /*to_type*/, const mpl::int_<number_kind_integer>& /*from_type*/)
{
   using default_ops::eval_get_sign;
   using default_ops::eval_bitwise_and;
   using default_ops::eval_convert_to;
   using default_ops::eval_right_shift;
   using default_ops::eval_left_shift;
   using default_ops::eval_bitwise_or;
   using default_ops::eval_is_zero;
   // smallest unsigned type handled natively by "From" is likely to be it's limb_type:
   typedef typename canonical<unsigned char, From>::type   limb_type;
   // get the corresponding type that we can assign to "To":
   typedef typename canonical<limb_type, To>::type         to_type;
   From t(from);
   bool is_neg = eval_get_sign(t) < 0;
   if(is_neg)
      t.negate();
   // Pick off the first limb:
   limb_type limb;
   limb_type mask = static_cast<limb_type>(~static_cast<limb_type>(0));
   From fl;
   eval_bitwise_and(fl, t, mask);
   eval_convert_to(&limb, fl);
   to = static_cast<to_type>(limb);
   eval_right_shift(t, std::numeric_limits<limb_type>::digits);
   //
   // Then keep picking off more limbs until "t" is zero:
   //
   To l;
   unsigned shift = std::numeric_limits<limb_type>::digits;
   while(!eval_is_zero(t))
   {
      eval_bitwise_and(fl, t, mask);
      eval_convert_to(&limb, fl);
      l = static_cast<to_type>(limb);
      eval_right_shift(t, std::numeric_limits<limb_type>::digits);
      eval_left_shift(l, shift);
      eval_bitwise_or(to, l);
      shift += std::numeric_limits<limb_type>::digits;
   }
   //
   // Finish off by setting the sign:
   //
   if(is_neg)
      to.negate();
}
开发者ID:1ack,项目名称:Impala,代码行数:46,代码来源:generic_interconvert.hpp

示例3: eval_exp

void eval_exp(cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> &res, const cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> &arg)
{
   //
   // This is based on MPFR's method, let:
   //
   // n = floor(x / ln(2))
   //
   // Then:
   //
   // r = x - n ln(2) : 0 <= r < ln(2)
   //
   // We can reduce r further by dividing by 2^k, with k ~ sqrt(n),
   // so if:
   //
   // e0 = exp(r / 2^k) - 1
   //
   // With e0 evaluated by taylor series for small arguments, then:
   //
   // exp(x) = 2^n (1 + e0)^2^k
   //
   // Note that to preserve precision we actually square (1 + e0) k times, calculating
   // the result less one each time, i.e.
   //
   // (1 + e0)^2 - 1 = e0^2 + 2e0
   //
   // Then add the final 1 at the end, given that e0 is small, this effectively wipes
   // out the error in the last step.
   //
   using default_ops::eval_multiply;
   using default_ops::eval_subtract;
   using default_ops::eval_add;
   using default_ops::eval_convert_to;

   int type = eval_fpclassify(arg);
   bool isneg = eval_get_sign(arg) < 0;
   if(type == (int)FP_NAN)
   {
      res = arg;
      errno = EDOM;
      return;
   }
   else if(type == (int)FP_INFINITE)
   {
      res = arg;
      if(isneg)
         res = limb_type(0u);
      else
         res = arg;
      return;
   }
   else if(type == (int)FP_ZERO)
   {
      res = limb_type(1);
      return;
   }
   cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> t, n;
   if(isneg)
   {
      t = arg;
      t.negate();
      eval_exp(res, t);
      t.swap(res);
      res = limb_type(1);
      eval_divide(res, t);
      return;
   }

   eval_divide(n, arg, default_ops::get_constant_ln2<cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> >());
   eval_floor(n, n);
   eval_multiply(t, n, default_ops::get_constant_ln2<cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> >());
   eval_subtract(t, arg);
   t.negate();
   if(eval_get_sign(t) < 0)
   {
      // There are some very rare cases where arg/ln2 is an integer, and the subsequent multiply
      // rounds up, in that situation t ends up negative at this point which breaks our invariants below:
      t = limb_type(0);
   }

   Exponent k, nn;
   eval_convert_to(&nn, n);

   if (nn == (std::numeric_limits<Exponent>::max)())
   {
      // The result will necessarily oveflow:
      res = std::numeric_limits<number<cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> > >::infinity().backend();
      return;
   }

   BOOST_ASSERT(t.compare(default_ops::get_constant_ln2<cpp_bin_float<Digits, DigitBase, Allocator, Exponent, MinE, MaxE> >()) < 0);

   k = nn ? Exponent(1) << (msb(nn) / 2) : 0;
   eval_ldexp(t, t, -k);

   eval_exp_taylor(res, t);
   //
   // Square 1 + res k times:
   //
   for(int s = 0; s < k; ++s)
   {
//.........这里部分代码省略.........
开发者ID:AbhinavJain13,项目名称:turicreate,代码行数:101,代码来源:transcendental.hpp

示例4: convert_to_string

std::string convert_to_string(Backend b, std::streamsize digits, std::ios_base::fmtflags f)
{
   using default_ops::eval_log10;
   using default_ops::eval_floor;
   using default_ops::eval_pow;
   using default_ops::eval_convert_to;
   using default_ops::eval_multiply;
   using default_ops::eval_divide;
   using default_ops::eval_subtract;
   using default_ops::eval_fpclassify;

   typedef typename mpl::front<typename Backend::unsigned_types>::type ui_type;
   typedef typename Backend::exponent_type exponent_type;

   std::string result;
   bool iszero = false;
   bool isneg = false;
   exponent_type expon = 0;
   std::streamsize org_digits = digits;
   BOOST_ASSERT(digits > 0);

   int fpt = eval_fpclassify(b);

   if(fpt == (int)FP_ZERO)
   {
      result = "0";
      iszero = true;
   }
   else if(fpt == (int)FP_INFINITE)
   {
      if(b.compare(ui_type(0)) < 0)
         return "-inf";
      else
         return ((f & std::ios_base::showpos) == std::ios_base::showpos) ? "+inf" : "inf";
   }
   else if(fpt == (int)FP_NAN)
   {
      return "nan";
   }
   else
   {
      //
      // Start by figuring out the exponent:
      //
      isneg = b.compare(ui_type(0)) < 0;
      if(isneg)
         b.negate();
      Backend t;
      Backend ten;
      ten = ui_type(10);

      eval_log10(t, b);
      eval_floor(t, t);
      eval_convert_to(&expon, t);
      if(-expon > std::numeric_limits<number<Backend> >::max_exponent10 - 3)
      {
         int e = -expon / 2;
         Backend t2;
         eval_pow(t2, ten, e);
         eval_multiply(t, t2, b);
         eval_multiply(t, t2);
         if(expon & 1)
            eval_multiply(t, ten);
      }
      else
      {
         eval_pow(t, ten, -expon);
         eval_multiply(t, b);
      }
      //
      // Make sure we're between [1,10) and adjust if not:
      //
      if(t.compare(ui_type(1)) < 0)
      {
         eval_multiply(t, ui_type(10));
         --expon;
      }
      else if(t.compare(ui_type(10)) >= 0)
      {
         eval_divide(t, ui_type(10));
         ++expon;
      }
      Backend digit;
      ui_type cdigit;
      //
      // Adjust the number of digits required based on formatting options:
      //
      if(((f & std::ios_base::fixed) == std::ios_base::fixed) && (expon != -1))
         digits += expon + 1;
      if((f & std::ios_base::scientific) == std::ios_base::scientific)
         ++digits;
      //
      // Extract the digits one at a time:
      //
      for(unsigned i = 0; i < digits; ++i)
      {
         eval_floor(digit, t);
         eval_convert_to(&cdigit, digit);
         result += static_cast<char>('0' + cdigit);
         eval_subtract(t, digit);
//.........这里部分代码省略.........
开发者ID:13W,项目名称:icq-desktop,代码行数:101,代码来源:float_string_cvt.hpp

示例5: eval_convert_to

inline void eval_convert_to(R* result, const debug_adaptor<Backend>& val)
{
   using default_ops::eval_convert_to;
   eval_convert_to(result, val.value());
}
开发者ID:AsherBond,项目名称:PDAL,代码行数:5,代码来源:debug_adaptor.hpp


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