本文整理汇总了C++中VectorXf::head方法的典型用法代码示例。如果您正苦于以下问题:C++ VectorXf::head方法的具体用法?C++ VectorXf::head怎么用?C++ VectorXf::head使用的例子?那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类VectorXf
的用法示例。
在下文中一共展示了VectorXf::head方法的2个代码示例,这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞,您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: call_ref
void call_ref()
{
VectorXcf ca = VectorXcf::Random(10);
VectorXf a = VectorXf::Random(10);
RowVectorXf b = RowVectorXf::Random(10);
MatrixXf A = MatrixXf::Random(10,10);
RowVector3f c = RowVector3f::Random();
const VectorXf& ac(a);
VectorBlock<VectorXf> ab(a,0,3);
const VectorBlock<VectorXf> abc(a,0,3);
VERIFY_EVALUATION_COUNT( call_ref_1(a,a), 0);
VERIFY_EVALUATION_COUNT( call_ref_1(b,b.transpose()), 0);
// call_ref_1(ac,a<c); // does not compile because ac is const
VERIFY_EVALUATION_COUNT( call_ref_1(ab,ab), 0);
VERIFY_EVALUATION_COUNT( call_ref_1(a.head(4),a.head(4)), 0);
VERIFY_EVALUATION_COUNT( call_ref_1(abc,abc), 0);
VERIFY_EVALUATION_COUNT( call_ref_1(A.col(3),A.col(3)), 0);
// call_ref_1(A.row(3),A.row(3)); // does not compile because innerstride!=1
VERIFY_EVALUATION_COUNT( call_ref_3(A.row(3),A.row(3).transpose()), 0);
VERIFY_EVALUATION_COUNT( call_ref_4(A.row(3),A.row(3).transpose()), 0);
// call_ref_1(a+a, a+a); // does not compile for obvious reason
MatrixXf tmp = A*A.col(1);
VERIFY_EVALUATION_COUNT( call_ref_2(A*A.col(1), tmp), 1); // evaluated into a temp
VERIFY_EVALUATION_COUNT( call_ref_2(ac.head(5),ac.head(5)), 0);
VERIFY_EVALUATION_COUNT( call_ref_2(ac,ac), 0);
VERIFY_EVALUATION_COUNT( call_ref_2(a,a), 0);
VERIFY_EVALUATION_COUNT( call_ref_2(ab,ab), 0);
VERIFY_EVALUATION_COUNT( call_ref_2(a.head(4),a.head(4)), 0);
tmp = a+a;
VERIFY_EVALUATION_COUNT( call_ref_2(a+a,tmp), 1); // evaluated into a temp
VERIFY_EVALUATION_COUNT( call_ref_2(ca.imag(),ca.imag()), 1); // evaluated into a temp
VERIFY_EVALUATION_COUNT( call_ref_4(ac.head(5),ac.head(5)), 0);
tmp = a+a;
VERIFY_EVALUATION_COUNT( call_ref_4(a+a,tmp), 1); // evaluated into a temp
VERIFY_EVALUATION_COUNT( call_ref_4(ca.imag(),ca.imag()), 0);
VERIFY_EVALUATION_COUNT( call_ref_5(a,a), 0);
VERIFY_EVALUATION_COUNT( call_ref_5(a.head(3),a.head(3)), 0);
VERIFY_EVALUATION_COUNT( call_ref_5(A,A), 0);
// call_ref_5(A.transpose(),A.transpose()); // does not compile because storage order does not match
VERIFY_EVALUATION_COUNT( call_ref_5(A.block(1,1,2,2),A.block(1,1,2,2)), 0);
VERIFY_EVALUATION_COUNT( call_ref_5(b,b), 0); // storage order do not match, but this is a degenerate case that should work
VERIFY_EVALUATION_COUNT( call_ref_5(a.row(3),a.row(3)), 0);
VERIFY_EVALUATION_COUNT( call_ref_6(a,a), 0);
VERIFY_EVALUATION_COUNT( call_ref_6(a.head(3),a.head(3)), 0);
VERIFY_EVALUATION_COUNT( call_ref_6(A.row(3),A.row(3)), 1); // evaluated into a temp thouth it could be avoided by viewing it as a 1xn matrix
tmp = A+A;
VERIFY_EVALUATION_COUNT( call_ref_6(A+A,tmp), 1); // evaluated into a temp
VERIFY_EVALUATION_COUNT( call_ref_6(A,A), 0);
VERIFY_EVALUATION_COUNT( call_ref_6(A.transpose(),A.transpose()), 1); // evaluated into a temp because the storage orders do not match
VERIFY_EVALUATION_COUNT( call_ref_6(A.block(1,1,2,2),A.block(1,1,2,2)), 0);
VERIFY_EVALUATION_COUNT( call_ref_7(c,c), 0);
}
示例2:
VectorXf SeedFeature::operator*( const VectorXf & o ) const {
eassert( o.size() == static_f_.cols() + dynamic_f_.cols() );
return static_f_*o.head(static_f_.cols()) + dynamic_f_*o.tail(dynamic_f_.cols());
}