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Fixes #1127

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array views were not handling negative strides properly.  Thanks to Phil Richards for pointing that out.


[SVN r38482]
This commit is contained in:
Ronald Garcia 2007-08-06 19:40:43 +00:00
parent 13259f4def
commit bcb10816f1
2 changed files with 27 additions and 2 deletions
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7
include/boost/multi_array/base.hpp
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@ -437,13 +437,16 @@ protected:
index start = current_range.get_start(default_start);
index finish = current_range.get_finish(default_finish);
index index_factor = current_range.stride();
index len = (finish - start + (index_factor - 1)) / index_factor;
// integral trick for ceiling((finish-start) / index_factor)
index shrinkage = index_factor > 0 ? 1 : -1;
index len = (finish - start + (index_factor - shrinkage)) / index_factor;
BOOST_ASSERT(index_bases[n] <= start &&
start <= index_bases[n]+index(extents[n]));
BOOST_ASSERT(index_bases[n] <= finish &&
finish <= index_bases[n]+index(extents[n]));
BOOST_ASSERT(index_factor > 0);
BOOST_ASSERT(index_factor != 0);
// the array data pointer is modified to account for non-zero
// bases during slicing (see [Garcia] for the math involved)

22
test/slice.cpp
View File

@ -90,6 +90,28 @@ void test_views(Array& A, const ViewTraits&) {
BOOST_CHECK(B(elmts) == A[idx0+i][idx1+1][idx2+j*2]);
}
}
// Flip the third dimension
{
typename ViewTraits::array_view3 B = A[
indices[range(idx0+0,idx0+2)]
[range(idx1+0,idx1+2)]
[range(idx2+2,idx2+0,-1)]
];
// typename ViewTraits::array_view3 B =
// A[indices[range(idx0+0,idx0+2)][idx1+1][range(idx2+0,idx2+4,2)]];
for (index i = 0; i != 2; ++i)
for (index j = 0; j != 2; ++j)
for (index k = 0; k != 2; ++k) {
BOOST_CHECK(B[i][j][k] == A[idx0+i][idx1+j][idx2+2-k]);
boost::array<index,3> elmts;
elmts[0]=i; elmts[1]=j; elmts[2]=k;
BOOST_CHECK(B(elmts) == A[idx0+i][idx1+j][idx2+2-k]);
}
}
++tests_run;
}