function t=trans(ie)
global node element
xi = node( element( ie, 1 ), 1 ) ;  %(兩端座標)
yi = node( element( ie, 1 ), 2 ) ;  %(兩端座標)
xj = node( element( ie, 2 ), 1 ) ;  %(兩端座標)
yj = node( element( ie, 2 ), 2 ) ;  %(兩端座標)
L = ( (xj-xi)^2 + (yj-yi)^2)^(1/2) ;  %(單元長度)
l1 = (xj-xi)/L ;    %(cosα)
m1 = (yj-yi)/L ;    %(cosβ)
      t=[  l1   -m1   0     0     0     0
           m1   l1    0     0     0     0
           0     0    1     0     0     0
           0    0     0     l1   -m1    0
           0    0     0     m1    l1    0
           0    0     0     0     0     1] ;    %(轉(zhuǎn)換矩陣)
return;