请教：flac3d 中table命令的含义和用法
这是说明中的示例：gen zone brick size 6 6 6
model elas
prop bulk 1e8 shear 7e7
fix x range x -0.1 0.1
table 1 100,1 100,-1e5
apply sxx 1.0 hist table 1 range x 5.9,6.1 y 0,6 z 0,2
hist zone sxx 6,0,0
step 100
plot create eg
plot add axes red scale 0.4
plot add surface yellow
plot show
命令参考中的说明是：
TABLE n <keyword> x1 y1 <x2 y2><x3 y3> : : :
This command sets up a table of x- and y-values for use by FLAC3D. Tables are used
to define:
(1) the variation of friction, cohesion and dilation with accumulated plastic shear
strain for the strain-softening model (see the PROP ftable, PROP ctable and PROP
dtable commands) or the variation of tensile strength with accumulated plastic
tensile strain (see the PROP ttable command); and
(2) histories of boundary conditions (see the APPLY command).
Multiple tables may be defined, each uniquely identified by a table number n. The
number of tables and x,y pairs are only limited by the amount of computer memory
available. The command PRINT table can be used to verify the contents of a table.
Individual tables can also be plotted using the PLOT table n command. Table numbers
need not be sequential, but they must not be zero.
Tables can also be created and manipulated with FISH functions. See Chapter 6 for
a description of FISH table functions.
Histories may also be copied to tables (see the HISTORY command). This allows the
user to perform post-processing on histories (by using FISH).
这里面x1 y1 <x2 y2><x3 y3> : : :是什么意思，他的含义是什么啊？
