findpiv.m

来自「GPS导航电文相关的计算程序」· M 代码 · 共 16 行

function [k,p] = findpiv(A,k,p,tol)
%FINDPIV Used by PLU to find a pivot for Gaussian elimination.
%	[r,p] = FINDPIV(A(k:m,p:n),k,p,tol) finds the first element in
%	the specified submatrix which is larger than tol in absolute value.
%	It returns indices r and p so that A(r,p) is the pivot.

[m,n] = size(A);
r = find(abs(A(:))>tol);
if isempty(r)
   return
end
r = r(1);
j = fix((r-1)/m)+1;
p = p+j-1;
k = k+r-(j-1)*m-1;