本文整理汇总了C++中Permutation::Swap方法的典型用法代码示例。如果您正苦于以下问题：C++ Permutation::Swap方法的具体用法？C++ Permutation::Swap怎么用？C++ Permutation::Swap使用的例子？那么, 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Permutation的用法示例。
在下文中一共展示了Permutation::Swap方法的1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: w
void LUMod
( Matrix<F>& A,
Permutation& P,
const Matrix<F>& u,
const Matrix<F>& v,
bool conjugate,
Base<F> tau )
{
DEBUG_CSE
typedef Base<F> Real;
const Int m = A.Height();
const Int n = A.Width();
const Int minDim = Min(m,n);
if( minDim != m )
LogicError("It is assumed that height(A) <= width(A)");
if( u.Height() != m || u.Width() != 1 )
LogicError("u is expected to be a conforming column vector");
if( v.Height() != n || v.Width() != 1 )
LogicError("v is expected to be a conforming column vector");
// w := inv(L) P u
auto w( u );
P.PermuteRows( w );
Trsv( LOWER, NORMAL, UNIT, A, w );
// Maintain an external vector for the temporary subdiagonal of U
Matrix<F> uSub;
Zeros( uSub, minDim-1, 1 );
// Reduce w to a multiple of e0
for( Int i=minDim-2; i>=0; --i )
{
// Decide if we should pivot the i'th and i+1'th rows of w
const F lambdaSub = A(i+1,i);
const F ups_ii = A(i,i);
const F omega_i = w(i);
const F omega_ip1 = w(i+1);
const Real rightTerm = Abs(lambdaSub*omega_i+omega_ip1);
const bool pivot = ( Abs(omega_i) < tau*rightTerm );
const Range<Int> indi( i, i+1 ),
indip1( i+1, i+2 ),
indB( i+2, m ),
indR( i+1, n );
auto lBi = A( indB, indi );
auto lBip1 = A( indB, indip1 );
auto uiR = A( indi, indR );
auto uip1R = A( indip1, indR );
if( pivot )
{
// P := P_i P
P.Swap( i, i+1 );
// Simultaneously perform
// U := P_i U and
// L := P_i L P_i^T
//
// Then update
// L := L T_{i,L}^{-1},
// U := T_{i,L} U,
// w := T_{i,L} P_i w,
// where T_{i,L} is the Gauss transform which zeros (P_i w)_{i+1}.
//
// More succinctly,
// gamma := w(i) / w(i+1),
// w(i) := w(i+1),
// w(i+1) := 0,
// L(:,i) += gamma L(:,i+1),
// U(i+1,:) -= gamma U(i,:).
const F gamma = omega_i / omega_ip1;
const F lambda_ii = F(1) + gamma*lambdaSub;
A(i, i) = gamma;
A(i+1,i) = 0;
auto lBiCopy = lBi;
Swap( NORMAL, lBi, lBip1 );
Axpy( gamma, lBiCopy, lBi );
auto uip1RCopy = uip1R;
RowSwap( A, i, i+1 );
Axpy( -gamma, uip1RCopy, uip1R );
// Force L back to *unit* lower-triangular form via the transform
// L := L T_{i,U}^{-1} D^{-1},
// where D is diagonal and responsible for forcing L(i,i) and
// L(i+1,i+1) back to 1. The effect on L is:
// eta := L(i,i+1)/L(i,i),
// L(:,i+1) -= eta L(:,i),
// delta_i := L(i,i),
// delta_ip1 := L(i+1,i+1),
// L(:,i) /= delta_i,
// L(:,i+1) /= delta_ip1,
// while the effect on U is
// U(i,:) += eta U(i+1,:)
// U(i,:) *= delta_i,
// U(i+1,:) *= delta_{i+1},
// and the effect on w is
// w(i) *= delta_i.
//.........这里部分代码省略.........