1549301742-The_Theory_of_Difference_Schemes__Samarskii

(jair2018) #1
Asymptotic stability 331

for the symmetric scheme with (} = ~ under the constraint T < 2 ( c5 b. )-^112.
We bring together the results obtained and state that

1
for
1+T0
(} = 1 and any T > 0,

p= 1 - T^0 for (} =^0 and


2
T < f 0 =
c5 + ,6.

,


1-1.To


(^2) for (} - 1. and T < T 0 =^2
l+~rc5




  • (^2) J[t;.
    In each such case the estimate II yJ II < pJ II y^0 II is certainly true. Moreover,
    pj --+ 0 occurs as tj = j T --+ oo. As we will see a little later, it will be
    convenient to represent p by
    T zp = μ 1 - log -
    p
    It is straightforward to verify that for (} = ~
    (^1) + (^1 2) μ1 ( μl (^3) μ1 5 )
    T zp = μ 1 - log l = - - + - + · · ·
    1 - - 2 μ 1 12 80
    It follows fron1 the foregoing that
    e -Ii t. J
    The regular behavior for the symmetric scheme with (} = ~ can be
    described as follows:




  • Y(x i> t j ) ~ c1 e-li tj+!l t.i ,". Y1(x.,), '




where


(

T2 03 T4 05 )
(3=- -+-+ 12 80 ··· =0(T^2 ) ,

In dealing with the pure implicit scheme we might have


(^1) -Tli
p = 1 +TD > e , p J. = e -lit·+f3t· J J

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