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Boost-Commit : |
From: john_at_[hidden]
Date: 2007-08-04 14:13:07
Author: johnmaddock
Date: 2007-08-04 14:13:04 EDT (Sat, 04 Aug 2007)
New Revision: 38445
URL: http://svn.boost.org/trac/boost/changeset/38445
Log:
Added another example to the policy tutorial.
Fixed \n warnings in the issue list.
Suppressed some Intel compiler messages.
Text files modified:
sandbox/math_toolkit/libs/math/doc/issues.qbk | 16 ++-
sandbox/math_toolkit/libs/math/doc/policy.qbk | 4 +
sandbox/math_toolkit/libs/math/example/error_handling_example.cpp | 148 ++++++++++++++++++++++++++++-----------
sandbox/math_toolkit/libs/math/test/Jamfile.v2 | 4 +
4 files changed, 123 insertions(+), 49 deletions(-)
Modified: sandbox/math_toolkit/libs/math/doc/issues.qbk
==============================================================================
--- sandbox/math_toolkit/libs/math/doc/issues.qbk (original)
+++ sandbox/math_toolkit/libs/math/doc/issues.qbk 2007-08-04 14:13:04 EDT (Sat, 04 Aug 2007)
@@ -37,20 +37,22 @@
[h4 Elliptic Integrals]
+[template para[text] '''<para>'''[text]'''</para>''']
+
* Carlson's algorithms are essentially unchanged from Xiaogang Zhang's
Google Summer of Code student project, and are based on Carlson's
original papers. However, Carlson has revised his algorithms since then
(refer to the references in the elliptic integral docs for a list), to
improve performance and accuracy, we may be able to take advantage
of these improvements too (Low Priority).
-* Carlson's algorithms (mainly R[sub J]) are somewhat prone to
+* [para Carlson's algorithms (mainly R[sub J]) are somewhat prone to
internal overflow/underflow when the arguments are very large or small.
-The homogeneity relations: \n
-R[sub F](ka, kb, kc) = k[super -1/2] R[sub F](a, b, c)\n
-and\n
-R[sub J](ka, kb, kc, kr) = k[super -3/2] R[sub J](a, b, c, r)\n
-could be used to sidestep trouble here: provided the problem domains
-can be accurately identified. (Medium Priority).
+The homogeneity relations:]
+[para R[sub F](ka, kb, kc) = k[super -1/2] R[sub F](a, b, c)]
+[para and]
+[para R[sub J](ka, kb, kc, kr) = k[super -3/2] R[sub J](a, b, c, r)]
+[para could be used to sidestep trouble here: provided the problem domains
+can be accurately identified. (Medium Priority).]
* Carlson's R[sub C] can be reduced to elementary funtions (asin and log),
would it be more efficient evaluated this way, rather than by Carlson's
algorithms? (Low Priority).
Modified: sandbox/math_toolkit/libs/math/doc/policy.qbk
==============================================================================
--- sandbox/math_toolkit/libs/math/doc/policy.qbk (original)
+++ sandbox/math_toolkit/libs/math/doc/policy.qbk 2007-08-04 14:13:04 EDT (Sat, 04 Aug 2007)
@@ -152,6 +152,10 @@
rule: but only because we know there will always be a single
translation unit only: don't say that you weren't warned!
+[import ../example/error_handling_example.cpp]
+
+[error_handling_example]
+
[heading Setting Policies for Distributions on an Ad Hoc Basis]
All of the statistical distributions in this library are class templates
Modified: sandbox/math_toolkit/libs/math/example/error_handling_example.cpp
==============================================================================
--- sandbox/math_toolkit/libs/math/example/error_handling_example.cpp (original)
+++ sandbox/math_toolkit/libs/math/example/error_handling_example.cpp 2007-08-04 14:13:04 EDT (Sat, 04 Aug 2007)
@@ -1,25 +1,51 @@
// example_error_handling.cpp
// Copyright Paul A. Bristow 2007.
-// Copyright John Maddock 2006.
+// Copyright John Maddock 2007.
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt
// or copy at http://www.boost.org/LICENSE_1_0.txt)
-// Shows use of macro definition to change policy for
-// domain_error - negative degrees of freedom argument
-// for student's t distribution CDF.
-
-// Uncomment this line to see the effect of changing policy,
-// to ignore the error & return NaN instead of throwing an exception.
-// #define BOOST_MATH_DOMAIN_ERROR_POLICY ignore_error
-// Note that these policy #defines MUST preceed the #include of
-// any boost/math #includes.
-// If placed after, they will have no effect!
-// warning C4005: 'BOOST_MATH_OVERFLOW_ERROR_POLICY' : macro redefinition
-// is a warning that it will NOT have the desired effect.
+// Note that this file contains quickbook markup as well as code
+// and comments, don't change any of the special comment markups!
+
+//[error_handling_example
+
+/*`
+The following example demonstrates the effect of
+setting the macro BOOST_MATH_DOMAIN_ERROR_POLICY
+when an invalid argument is encountered. For the
+purposes of this example we'll pass a negative
+degrees of freedom parameter to the student's t
+distribution.
+
+Since we know that this is a single file program we could
+just add:
+
+ #define BOOST_MATH_DOMAIN_ERROR_POLICY ignore_error
+
+to the top of the source file to change the default policy
+to one that simply returns a NaN when a domain error occurs.
+Alternatively we could use:
+
+ #define BOOST_MATH_DOMAIN_ERROR_POLICY errno_on_error
+
+To ensure the `::errno` is set when a domain error occurs
+as well as returning a NaN.
+
+This is safe provided the program consists of a single
+translation unit /and/ we place the define /before/ any
+#includes. Note that should we add the define after the includes
+then it will have no effect! A warning such as:
+
+[pre warning C4005: 'BOOST_MATH_OVERFLOW_ERROR_POLICY' : macro redefinition]
+
+is a certain sign that it will /not/ have the desired effect.
+
+We'll begin our sample program with the needed includes:
+*/
// Boost
#include <boost/math/distributions/students_t.hpp>
@@ -33,47 +59,85 @@
#include <stdexcept>
using std::exception;
-int main()
-{ // Example of error handling of bad argument(s) to a distribution.
- cout << "Example error handling using Student's t function. " << endl;
+/*`
- double degrees_of_freedom = -1; double t = -1.; // Bad arguments!
- // If we use
- // cout << "Probability of Student's t is " << cdf(students_t(-1), -1) << endl;
- // Will terminate/abort (without try & catch blocks)
- // if BOOST_MATH_DOMAIN_ERROR_POLICY has the default value throw_on_error.
-
- try
- {
- cout << "Probability of Student's t is " << cdf(students_t(degrees_of_freedom), t) << endl;
- }
- catch(const std::exception& e)
- {
- std::cout <<
- "\n""Message from thrown exception was:\n " << e.what() << std::endl;
- }
+Next we'll define the program's main() to call the student's t
+distribution with an invalid degrees of freedom parameter, the program
+is set up to handle either an exception or a NaN:
- return 0;
+*/
+
+int main()
+{
+ cout << "Example error handling using Student's t function. " << endl;
+ cout << "BOOST_MATH_DOMAIN_ERROR_POLICY is set to: "
+ << BOOST_STRINGIZE(BOOST_MATH_DOMAIN_ERROR_POLICY) << endl;
+
+ double degrees_of_freedom = -1; // A bad argument!
+ double t = 10;
+
+ try
+ {
+ errno = 0;
+ students_t dist(degrees_of_freedom); // exception is thrown here if enabled
+ double p = cdf(dist, t);
+ // test for error reported by other means:
+ if((boost::math::isnan)(p))
+ {
+ cout << "cdf returned a NaN!" << endl;
+ cout << "errno is set to: " << errno << endl;
+ }
+ else
+ cout << "Probability of Student's t is " << p << endl;
+ }
+ catch(const std::exception& e)
+ {
+ std::cout <<
+ "\n""Message from thrown exception was:\n " << e.what() << std::endl;
+ }
+
+ return 0;
} // int main()
-/*
+/*`
-Output:
+Here's what the program output looks like with a default build
+(one that does throw exceptions):
+[pre
Example error handling using Student's t function.
+BOOST_MATH_DOMAIN_ERROR_POLICY is set to: throw_on_error
-With
+Message from thrown exception was:
+ Error in function boost::math::students_t_distribution<double>::students_t_distribution: Degrees of freedom argument is -1, but must be > 0 !
+]
-#define BOOST_MATH_DOMAIN_ERROR_POLICY ignore_error
+Alternatively let's build with:
-Example error handling using Student's t function.
-Probability of Student's t is 1.#QNAN
+ #define BOOST_MATH_DOMAIN_ERROR_POLICY ignore_error
-Default behaviour without:
+Now the program output is:
-Example error handling using Student's t function.
-Message from thrown exception was:
- Error in function boost::math::students_t_distribution<double>::students_t_distribution: Degrees of freedom argument is -1, but must be > 0 !
+[pre
+Example error handling using Student's t function.
+BOOST_MATH_DOMAIN_ERROR_POLICY is set to: ignore_error
+cdf returned a NaN!
+errno is set to: 0
+]
+
+And finally let's build with:
+
+ #define BOOST_MATH_DOMAIN_ERROR_POLICY errno_on_error
+Which gives the output:
+
+[pre
+Example error handling using Student's t function.
+BOOST_MATH_DOMAIN_ERROR_POLICY is set to: errno_on_error
+cdf returned a NaN!
+errno is set to: 33
+]
*/
+
+//] end quickbook markup
Modified: sandbox/math_toolkit/libs/math/test/Jamfile.v2
==============================================================================
--- sandbox/math_toolkit/libs/math/test/Jamfile.v2 (original)
+++ sandbox/math_toolkit/libs/math/test/Jamfile.v2 2007-08-04 14:13:04 EDT (Sat, 04 Aug 2007)
@@ -13,6 +13,8 @@
<toolset>darwin:<cxxflags>-Wno-missing-braces
<toolset>acc:<cxxflags>+W2068,2461,2236,4070
<toolset>intel:<cxxflags>-Qwd264,239
+ <toolset>intel:<cxxflags>/nologo
+ <toolset>intel:<linkflags>/nologo
<toolset>msvc:<warnings>all
<toolset>msvc:<asynch-exceptions>on
<toolset>msvc:<cxxflags>/wd4996
@@ -183,3 +185,5 @@
+
+
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