boost_mirror/math
1
0
Fork 0
mirror of https://github.com/boostorg/math.git synced 2025-05-11 21:33:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

Added two more lambert_w examples and requires cxx_numeric_limits

Browse Source
This commit is contained in:
pabristow 2018-10-09 12:53:11 +01:00
parent ea42a834cc
commit 20067e75e5
3 changed files with 24 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
example/Jamfile.v2
View File

@ -72,6 +72,10 @@ test-suite examples :
[ run legendre_stieltjes_example.cpp : : : [ requires cxx11_auto_declarations cxx11_defaulted_functions cxx11_lambdas ] ]
#[ # run inverse_chi_squared_find_df_example.cpp ]
[ run lambert_w_basic_example.cpp ]
#[ run lambert_w_basic_example.cpp : : : [ requires cxx11_numeric_limits ] ]
[ run lambert_w_simple_examples.cpp : : : [ requires cxx11_numeric_limits ] ]
[ run lambert_w_precision_example.cpp : : : [ requires cxx11_numeric_limits ] ]
[ run inverse_gamma_example.cpp ]
[ run inverse_gamma_distribution_example.cpp : : : <exception-handling>off:<build>no ]

10
example/lambert_w_basic_example.cpp
View File

@ -4,6 +4,10 @@
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)
// Example of most basic call of both lambert W functions.
// Only requires C++03
// (and optionally a call of max_digits10 to show precision).
#include <boost/math/special_functions/lambert_w.hpp> // For lambert_w0 and wm1 functions.
#include <iostream>
@ -14,8 +18,10 @@ int main()
double z = 2.0;
double w0 = boost::math::lambert_w0(z);
std::cout.setf(std::ios_base::showpoint); // Include any trailing zeros.
// std::cout.precision(std::numeric_limits<double>::max_digits10); // Show all possibly significant digits.
// Avoid using max_digfigs10 so as many old compilers can run the most basic lambert_w0 test.
std::cout.precision(std::numeric_limits<double>::max_digits10); // Show all possibly significant digits.
// Avoid using max_digfigs10 so as many old compilers can run the most basic lambert_w0 test?
// Require to get max_digits10
// [ run lambert_w_basic_example.cpp : : : [ requires cxx11_numeric_limits ] ]
std::cout << " lambert_w0(" << z << ") = " << w0 << std::endl; // lambert_w0(2.00000) = 0.852606
z = -0.2;
double wm1 = boost::math::lambert_wm1(z);

29
example/lambert_w_precision_example.cpp
View File

@ -4,7 +4,7 @@
// (See accompanying file LICENSE_1_0.txt or
// copy at http ://www.boost.org/LICENSE_1_0.txt).
//! Lambert W examples of controlling precision
//! Lambert W examples of controlling precision
// #define BOOST_MATH_INSTRUMENT_LAMBERT_W // #define only for (much) diagnostic output.
@ -76,16 +76,16 @@ int main()
std::cout.precision(std::numeric_limits<cpp_bin_float_50>::digits10);
r = lambert_w0(z); // Default policy.
std::cout << "lambert_w0(z) cpp_bin_float_50 = " << r << std::endl;
std::cout << "lambert_w0(z) cpp_bin_float_50 = " << r << std::endl;
//lambert_w0(z) cpp_bin_float_50 = 1.7455280027406993830743012648753899115352881290809
// [N[productlog[10], 50]] == 1.7455280027406993830743012648753899115352881290809
std::cout.precision(std::numeric_limits<double>::max_digits10);
std::cout << "lambert_w0(z) static_cast from cpp_bin_float_50 = "
<< static_cast<double>(r) << std::endl;
<< static_cast<double>(r) << std::endl;
// double lambert_w0(z) static_cast from cpp_bin_float_50 = 1.7455280027406994
// [N[productlog[10], 17]] == 1.7455280027406994
std::cout << "bits different from Wolfram = "
<< static_cast<int>(float_distance(static_cast<double>(r), 1.7455280027406994))
std::cout << "bits different from Wolfram = "
<< static_cast<int>(float_distance(static_cast<double>(r), 1.7455280027406994))
<< std::endl; // 0
@ -96,7 +96,7 @@ int main()
std::cout << std::showpoint << std::endl; // and show any significant trailing zeros too.
float x = 10.;
std::cout << "Lambert W (" << x << ") = " << lambert_w0(x) << std::endl;
std::cout << "Lambert W (" << x << ") = " << lambert_w0(x) << std::endl;
//] [/lambert_w_precision_0]
/*
@ -118,7 +118,7 @@ Lambert W (10.0000000) = 1.74552800
cpp_bin_float_50 w50;
w50 = lambert_w0(z50);
std::cout.precision(std::numeric_limits<cpp_bin_float_50>::max_digits10); // 50 decimal digits.
std::cout << "Reference Lambert W (" << z << ") =\n "
std::cout << "Reference Lambert W (" << z << ") =\n "
<< w50 << std::endl;
std::cout.precision(std::numeric_limits<double>::max_digits10); // 17 decimal digits for double.
double wr = static_cast<double>(w50);
@ -136,7 +136,7 @@ Lambert W (10.0000000) = 1.74552800
std::cout << "epsilon for float = " << std::numeric_limits<double>::epsilon() << std::endl;
std::cout << "bits different from Halley step = " << static_cast<int>(float_distance(w, ww)) << std::endl;
//] [/lambert_w_precision_1]
/*
//[lambert_w_precision_output_1
@ -169,7 +169,7 @@ Lambert W (10.0000000) = 1.74552800
cpp_bin_float_50 wm1_50;
wm1_50 = lambert_wm1(z50);
std::cout.precision(std::numeric_limits<cpp_bin_float_50>::max_digits10); // 50 decimal digits.
std::cout << "Reference Lambert W-1 (" << z << ") =\n "
std::cout << "Reference Lambert W-1 (" << z << ") =\n "
<< wm1_50 << std::endl;
std::cout.precision(std::numeric_limits<double>::max_digits10); // 17 decimal digits for double.
double wr = static_cast<double>(wm1_50);
@ -204,7 +204,7 @@ Lambert W (10.0000000) = 1.74552800
*/
// Similar example using cpp_bin_float_quad (128-bit floating-point types).
cpp_bin_float_quad zq = 10.;
@ -235,7 +235,7 @@ Lambert W (10.0000000) = 1.74552800
std::cout.precision(std::numeric_limits<cpp_bin_float_quad>::digits10); // 1.745528002740699383074301264875389837
std::cout << "lambert_w0(z) cpp_dec_float_50 cast to quad (digits10(" << std::numeric_limits<cpp_bin_float_quad>::digits10 <<
" ) = " << static_cast<cpp_bin_float_quad>(r) << std::endl; // 1.74552800274069938307430126487539
std::cout.precision(std::numeric_limits<cpp_bin_float_quad>::digits10 + 1); //
std::cout.precision(std::numeric_limits<cpp_bin_float_quad>::digits10 + 1); //
std::cout << "lambert_w0(z) cpp_dec_float_50 cast to quad (digits10(" << std::numeric_limits<cpp_bin_float_quad>::digits10 <<
" ) = " << static_cast<cpp_bin_float_quad>(r) << std::endl; // 1.74552800274069938307430126487539
@ -259,11 +259,6 @@ Lambert W (10.0000000) = 1.74552800
}
} // int main()
/*
*/