matlab slash,bslashtx.m 源代码在线查看 - numerical computing with matlab by matthewlewin 例子资源下载虫虫电子下载站...

朴灿烈づ我的快乐病毒、 2023-01-15 08:02 59阅读 0赞

function x = bslashtx(A,b)% BSLASHTX Solve linear system (backslash)% x = bslashtx(A,b) solves A\*x = b\[n,n\] = size(A);if isequal(triu(A,1),zeros(n,n)) % Lower triangular x = forward(A,b); returnelseif isequal(tril(A,-1),zeros(n,n)) % Upper triangular x = backsubs(A,b); returnelseif isequal(A,A') \[R,fail\] = chol(A); if ~fail % Positive definite y = forward(R',b); x = backsubs(R,y); return endend% Triangular factorization\[L,U,p\] = lutx(A);% Permutation and forward eliminationy = forward(L,b(p));% Back substitutionx = backsubs(U,y);% ------------------------------function x = forward(L,x)% FORWARD. Forward elimination.% For lower triangular L, x = forward(L,b) solves L\*x = b.\[n,n\] = size(L);x(1) = x(1)/L(1,1);for k = 2:n j = 1:k-1; x(k) = (x(k) - L(k,j)\*x(j))/L(k,k);end% ------------------------------function x = backsubs(U,x)% BACKSUBS. Back substitution.% For upper triangular U, x = backsubs(U,b) solves U\*x = b.\[n,n\] = size(U);x(n) = x(n)/U(n,n);for k = n-1:-1:1 j = k+1:n; x(k) = (x(k) - U(k,j)\*x(j))/U(k,k);end