24小时热门版块排行榜

>论坛更新日志 (1275)
>虫友互识 (65)
>论文投稿 (43)
>休闲灌水 (40)
>论文道贺祈福 (31)
>导师招生 (27)
>基金申请 (21)
>考研 (20)
>教师之家 (17)
>硕博家园 (17)
>找工作 (15)
>考博 (12)
>公派出国 (8)
>博后之家 (5)
>经济学 (2)
>复合材料 (2)

返回列表

zouji1983

金虫 (正式写手)

应助: 6 (幼儿园)
金币: 567.4
散金: 2
红花: 3
帖子: 323
在线: 550.6小时
虫号: 445773
注册: 2007-10-28
性别: GG
专业: 材料科学

[求助] 求助：ludcmp&lubksb

subroutine ludcmp(coeff, numvar, np, indx, d)
integer :: numvar, np, indx(numvar)
doubleprecision :: d, coeff(np,np)
integer, parameter :: nmax=500
doubleprecision, parameter :: tiny=1.0d-20
integer :: i, imax, j, k
doubleprecision :: aamax, dum, sum, vv(nmax)
d=1
do i = 1, numvar
aamax = 0.d0
do j = 1, numvar
if (abs(coeff(i,j)).gt.aamax) aamax = abs(coeff(i,j))
end do
!if (aamax .eq. 0.d0) pause 'singular matrix in ludcmp'
vv(i) = 1./aamax
end do
do j = 1, numvar
do i= 1, j-1
sum = coeff(i,j)
do k=1,i-1
sum = sum-coeff(i,k)*coeff(k,j)
end do
coeff(i,j) = sum
end do
aamax = 0.d0
do i = j,numvar
sum = coeff(i,j)
do k=1, j-1
sum = sum - coeff(i,k) * coeff(k,j)
end do
coeff(i,j) = sum
dum = vv(i) * abs(sum)
if (dum .ge. aamax) then
imax = i
aamax = dum
end if
end do
if (j .ne. imax) then
do k = 1, numvar
dum = coeff(imax,k)
coeff(imax,k) = coeff(j,k)
coeff(j,k) = dum
end do
d = -d
vv(imax) = vv(j)
end if

indx(j) = imax
if (coeff(j,j) .eq. 0.d0) coeff(j,j) = tiny
if (j .ne. numvar) then
dum = 1./coeff(j,j)
do i = j+1, numvar
coeff(i,j) = coeff(i,j) * dum
end do
end if
end do
return
end subroutine ludcmp

请教，这个的功能是怎样的，谢谢！

回复此楼