16.4 Computer Program for Free Vibration Analysis of Framed Structures
575
Table 16.3 (continued)
subroutine bac
**
Solves lt*v=u by Back Substitution
**
parameter (ielt=50,inod=50,ntdf=inod*6,inb=50)
parameter (ibh=25,itdf=ntdf*ibh)
common /a/ npt,nbh,l(itdf),g(itdf),u(ntdf),ld(ntdf),gd(ntdf)
real l
integer q
do 20 i=1,npt
20
u(i)=u(i)/l(ld(i))
do 22 it=2,npt
i=npt+2-it
i1=i-1
q=ld(i)-i
m1=1+ld(i-1)-q
if(m1-i)10,22,10
10
continue
do 21 j=m1,i1
u(j)=u(j)-l(j+q)*u(i)/l(ld(j))
21
continue
22
continue
return
end
*
Subroutine For
subroutine for
**
Solves lv=u by Forward Substitution
**
parameter (ielt=50,inod=50,ntdf=inod*6,inb=50)
parameter (ibh=25,itdf=ntdf*ibh)
common /a/ npt,nbh,l(itdf),g(itdf),u(ntdf),ld(ntdf),gd(ntdf)
real l
integer q
u(1)=u(1)/l(1)
do 13 i=2,npt
q=ld(i)-i
m1=1+ld(i-1)-q
el=0.0
if(m1-i)10,13,10
10
continue
i1=i-1
do 14 j=m1,i1
14
el=el+l(j+q)*u(j)
13
u(i)=(u(i)-el)/l(ld(i))
return
end
*
Subroutine Decom
subroutine decom(ier)
**
Decomposes a Symmetric matrix into Cholesky Factors
**
parameter (ielt=50,inod=50,ntdf=inod*6,inb=50)
parameter (ibh=25,itdf=ntdf*ibh)
common /a/ npt,nbh,l(itdf),g(itdf),u(ntdf),ld(ntdf),gd(ntdf)
real l
(continued)