pivot.m

来自「用matlab写的一些数值算法」· M 代码 · 共 12 行

function  [A, b] = pivot(A, b, k)
% Find k'th pivot row and interchange

% Version 11.12.2003.  INCBOX

n = size(A,1);
[piv, q] = max(abs(A(k:n,k)));
if  q > 1  % interchange
  pk = k-1 + q;                            % row index
  A([k pk],:) = A([pk k],:);      % swap rows pk and k
  b([k pk]) = b([pk k]);      % swap elements pk and k
end