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<H3>BOOST_WARN_CLOSE( left, right, tolerance )<BR>
BOOST_CHECK_CLOSE( left, right, tolerance )<BR>
BOOST_REQUIRE_CLOSE( left, right, tolerance )</H3>
<P class="first-line-indented">These tools are used to check <I>left</I> and <I>right</I> values
on closeness using strong relationship defined by the predicate <A href="../floating_point_comparison.html" target="_top">close_at_tolerance
</A>( tolerance_src ). To check for the weak relationship use <A href="BOOST_CHECK_PREDICATE.html">BOOST_<level>_PREDICATE</A>
tools. Note that to use these tools you need to include additional header<A href="../../../../../../boost/test/floating_point_comparison.hpp">
floating_point_comparison.hpp</A>. </P>
<P class="first-line-indented">The first parameter is the <I>left</I> compared
value. The second parameter is the <I>right</I> compared value. Last third parameter defines the tolerance for
the comparison in percentage units. For more details how to treat this value
see <A href="../floating_point_comparison.html" target="_top">close_at_tolerance </A>description.
Note that it required for <I>left</I> and <I>right</I> parameters to be of the same floating point
type. You need to explicitly resolve any type mismatch to select which type to use for comparison.</P>
<H4>Example: test.cpp</H4>
<PRE class="code"><SPAN class="cpp-type">int</SPAN> test_main( <SPAN class="cpp-type">int</SPAN>, <SPAN class="cpp-type">char</SPAN>* [] ) {
<SPAN class="cpp-type">double</SPAN> v1 = <SPAN class="literal">1.23456e-10</SPAN>;
<SPAN class="cpp-type">double</SPAN> v2 = <SPAN class="literal">1.23457e-10</SPAN>;
BOOST_CHECK_CLOSE( v1, v2, <SPAN class="literal">0.0001</SPAN> );
<SPAN class="comment">// Absolute value of difference between these two values is 1e-15. They seems
// to be very close. But we want to checks that these values differ no more then 0.0001%
// of their value. And this test will fail at tolerance supplied</SPAN>.
<SPAN class="reserv-word">return</SPAN> <SPAN class="literal">0</SPAN>;
}</PRE>
<H4>Output:</H4>
<P class="test-output">test.cpp(4) : error in test_main: difference between
v1{1.23456e-10} and v2{1.23457e-10} exeeds 1e-04%</P>
<H4>Example: test.cpp</H4>
<PRE class="code"><SPAN class="cpp-type">int</SPAN> test_main( <SPAN class="cpp-type">int</SPAN>, <SPAN class="cpp-type">char</SPAN>* [] ) {
<SPAN class="cpp-type">double</SPAN> v1 = <SPAN class="literal">1.23456e28;</SPAN>
<SPAN class="cpp-type">double</SPAN> v2 = <SPAN class="literal">1.23457e28;</SPAN>
BOOST_REQUIRE_CLOSE( v1, v2, <SPAN class="literal">0.001</SPAN> );
<SPAN class="comment">// Absolute value of difference between these two values is 1e+23.
// But we are interested only that it does not exeed 0.001% of a values compared
// And this test will pass.</SPAN>
<SPAN class="reserv-word">return</SPAN> <SPAN class="literal">0</SPAN>;
}</PRE>
<H4>Output:</H4>
<P class="test-output"> </P>
<DIV class="see_also">
<H4>See Also</H4>
<P class="see-also-content"><A href="BOOST_CHECK_EQUAL.html" target="descr">BOOST_CHECK_EQUAL</A>,
<A href="../floating_point_comparison.html" target="_top">Floating point comparison algorithms</A></P>
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