Subject: [Boost-commit] svn:boost r49515 - sandbox/math_toolkit/libs/math/example
From: pbristow_at_[hidden]
Date: 2008-11-01 10:18:09
Author: pbristow
Date: 2008-11-01 10:18:09 EDT (Sat, 01 Nov 2008)
New Revision: 49515
URL: http://svn.boost.org/trac/boost/changeset/49515
Log:
Removed wrongly pasted stuff and re-ran. May not yet be used in qbk docs
Text files modified:
sandbox/math_toolkit/libs/math/example/find_root_example.cpp | 94 +++++----------------------------------
1 files changed, 12 insertions(+), 82 deletions(-)
Modified: sandbox/math_toolkit/libs/math/example/find_root_example.cpp
==============================================================================
--- sandbox/math_toolkit/libs/math/example/find_root_example.cpp (original)
+++ sandbox/math_toolkit/libs/math/example/find_root_example.cpp 2008-11-01 10:18:09 EDT (Sat, 01 Nov 2008)
@@ -31,87 +31,6 @@
using std::numeric_limits;
//] //[/root_find1]
-namespace boost{ namespace math { namespace tools
-{
-
-template <class F, class T, class Tol>
-inline std::pair<T, T> bracket_and_solve_root(F f, // functor
- const T& guess,
- const T& factor,
- bool rising,
- Tol tol, // binary functor specifying termination when tol(min, max) becomes true.
- // eps_tolerance most suitable for this continuous function
- boost::uintmax_t& max_iter); // explicit (rather than default) max iterations.
-// return interval as a pair containing result.
-
-namespace detail
-{
-
- // Functor for finding standard deviation:
- template <class RealType, class Policy>
- struct standard_deviation_functor
- {
- standard_deviation_functor(RealType m, RealType s, RealType d)
- : mean(m), standard_deviation(s)
- {
- }
- RealType operator()(const RealType& sd)
- { // Unary functor - the function whose root is to be found.
- if(sd <= tools::min_value<RealType>())
- { //
- return 1;
- }
- normal_distribution<RealType, Policy> t(mean, sd);
- RealType qa = quantile(complement(t, alpha));
- RealType qb = quantile(complement(t, beta));
- qa += qb;
- qa *= qa;
- qa *= ratio;
- qa -= (df + 1);
- return qa;
- } // operator()
- RealType mean;
- RealType standard_deviation;
- }; // struct standard_deviation_functor
-} // namespace detail
-
-template <class RealType, class Policy>
-RealType normal_distribution<RealType, Policy>::find_standard_deviation(
- RealType difference_from_mean,
- RealType mean,
- RealType sd,
- RealType hint) // Best guess available - current sd if none better?
-{
- static const char* function = "boost::math::normal_distribution<%1%>::find_standard_deviation";
-
- // Check for domain errors:
- RealType error_result;
- if(false == detail::check_probability(
- function, sd, &error_result, Policy())
- )
- return error_result;
-
- if(hint <= 0)
- { // standard deviation can never be negative.
- hint = 1;
- }
-
- detail::standard_deviation_functor<RealType, Policy> f(mean, sd, difference_from_mean);
- tools::eps_tolerance<RealType> tol(policies::digits<RealType, Policy>());
- boost::uintmax_t max_iter = 100;
- std::pair<RealType, RealType> r = tools::bracket_and_solve_root(f, hint, RealType(2), false, tol, max_iter, Policy());
- RealType result = r.first + (r.second - r.first) / 2;
- if(max_iter == 100)
- {
- policies::raise_evaluation_error<RealType>(function, "Unable to locate solution in a reasonable time:"
- " either there is no answer to how many degrees of freedom are required"
- " or the answer is infinite. Current best guess is %1%", result, Policy());
- }
- return result;
-} // find_standard_deviation
-} // namespace tools
-} // namespace math
-} // namespace boost
int main()
@@ -231,9 +150,20 @@
} // int main()
/*
-
Output is:
+//[root_find_output
+Autorun "i:\boost-06-05-03-1300\libs\math\test\Math_test\debug\find_root_example.exe"
+Example: Normal distribution, root finding.Percentage of packs > 3.1 is 0.158655
+fraction of packs <= 2.9 with a mean of 3 is 0.841345
+fraction of packs >= 2.9 with a mean of 3.0664 is 0.951944
+Setting the packer to 3.06449 will mean that fraction of packs >= 2.9 is 0.95
+Quantile of 0.05 = 2.83551, mean = 3, sd = 0.1
+Quantile of 0.05 = 2.91776, mean = 3, sd = 0.05
+Fraction of packs >= 2.9 with a mean of 3 and standard deviation of 0.05 is 0.97725
+Quantile of 0.05 = 2.90131, mean = 3, sd = 0.06
+Fraction of packs >= 2.9 with a mean of 3 and standard deviation of 0.06 is 0.95221
+//] [/root_find_output]
*/