556
Available at http://pvamu.edu/aam
Appl. Appl. Math.
ISSN: 1932-9466
Vol. 7, Issue 2 (December 2012), pp. 556 - 570
Applications and Applied Mathematics:
An International Journal (AAM)
On The Numerical Solution of Linear Fredholm-Volterra İntegro Differential Difference Equations With Piecewise İntervals
Mustafa Gülsu and Yalçın Öztürk
Deparment of Mathematics Mugla University
Mugla,Turkey [email protected]; [email protected]
Received:August 03, 2011; Accepted: October 6, 2012
Abstract The numerical solution of a mixed linear integro delay differential-difference equation with piecewise interval is presented using the Chebyshev collocation method. The aim of this article is to present an efficient numerical procedure for solving a mixed linear integro delay differential difference equations. Our method depends mainly on a Chebyshev expansion approach. This method transforms a mixed linear integro delay differential-difference equations and the given conditions into a matrix equation which corresponds to a system of linear algebraic equation. The reliability and efficiency of the proposed scheme are demonstrated by some numerical experiments and performed on the computer algebraic system Maple 10.
Keywords: Mixed linear integro delay differential-difference equations; Chebyshev polynomials and series; Approximation methods; Collocation points
MSC 2010 No.: 41A58; 39A10; 34K28; 41A10
1. Introduction In recent years, the studies of mixed integro delay differential-difference equations have developed very rapidly. These equations may be classified into two types; the Fredholm integro-differential-difference equations and Volterra integro-differential-difference equations. The upper bound of the integral part of Volterra type is variable, while it is a fixed number for that of
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 557
Fredholm type. In this paper we focus on Fredholm Volterra integro differential difference equations with piecewise intervals. Integro-differential-difference equations are important, but are often harder to solve, even numerically, and progress on how to solve them has been slow. Problems involving these equations arise frequently in many applied areas including engineering, mechanics, physics, chemistry, astronomy, biology, economics, potential theory, electrostatics, etc. [Emler (2001,2002), Ren (1999), Rashed (2004), Kadalbajoo (2002,2004), Bainov (2000), Cao (2004),]: The study of integro differential difference equations has great interest in contemporary research work. Several numerical methods, such as the successive approximations, Adomian decomposition, Chebyshev and Taylor collocation, Haar Wavelet, Tau and Walsh series methods, etc. [Ortiz (1998), Hosseini (2003), Zhao (2006), Maleknejad (2006), Sezer (2005a, 2005b), Synder (1966), Gülsu (2010)] are used for their solution. Mainly we deal with the following integro delay differential-difference equation with piecewise intervals
v
j
x
a
jj
u
i
b
a
ii
n
s
ss
m
k
kk
j
i
i
dttytxKdttytxF
xgxyxHxyxP
00
0
)(
0
)(
)(),()(),(
)()()()()(
(1)
]0,[ x , 1,,1 jii cba under the mixed conditions
1,...1,0,0,)(1
0 0
)(
miccyc ij
m
ki
r
jij
kij
k , (2)
where )(xy is an unknown function, the known )(xPk , )(xH s , ),( txFi , ),( txK j and )(xg are
defined on an interval and also kijc , ijc , i and s are appropriate constant. Our aim is to find an
approximate solution expressed in the form
N
rrr xTaxy
0
)()( , 0 i N , (3)
where Nrar ,...,2,1,0, , are unknown coefficients and N is any chosen positive integer such that mN . To obtained a solution in the form(3) of the problem (1) and (2), we may use the collocation points defined by
NiN
ixi ,,2,1,0,)cos(1
2
. (4)
The remainder of the paper is organized as follows: Higher-order linear mixed integro-delay-differential-difference equation with variable coefficients with piecewise intervals and fundamental relations are presented in Section 2. The method of finding approximate solution is described in Section 3. To support our findings, we present numerical results of some experiments using Maple10 in Section 4. Section 5 concludes this article with a brief summary.
558 M. Gülsu and Y. Öztürk
2. Fundamental Matrix Relations Let us write Eq.(1) in the form
v
jjj
u
iii xJxIxgxHxD
00
)()()()()( ,
where the differential part
m
k
kk xyxPxD
0
)( )()()(
and the difference part
n
s
ss xyxHxH
0
)( )()()(
the Fredholm integral part
dttytxFxIi
i
b
a
ii )(),()(
and Volterra integral part
dttytxKxJx
c
jj
j
)(),()( .
We convert these equations and the mixed conditions in to the matrix form. Let us consider the Eq. (1) and find the matrix forms of each term of the equation. We first consider the solution
)(xy and its derivative )()( xy k defined by a truncated Chebyshev series. Then we can put series in the matrix form
AT )()( xxy , AT )()( )()( xxy kk , (5)
where
)](...)()([)( 210 xTxTxTx T , )](...)()([)( )()(1
)(0
)( xTxTxTx kN
kkk T , TNaaa ]...[ 10A .
On the other hand, it is well known that [Synder (1966)] the relation between the powers nx and the Chebyshev polynomials )(xTn is
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 559
,11,)(2
20
2122
xxTjn
nx
n
jj
nn (6)
and
.11,)(12
20
12212
xxT
jn
nx
n
jj
nn (7)
Using the expression (6) and (7) and taking Nn ...,,1,0 , we obtain the corresponding matrix relation as follows:
)()( xx TT DTX and ,))(()( 1 Txx DTX (8)
where
TNxx ]...1[ 1X . for odd N,
NN N
N
N 11
11
0
1
20
022/)1(
0
020
202
1
2
2
1
0020
10
00020
0
2
1
D
and for even N,
NNN N
N
N
N
N 111
11
0
1
20
22/)2(
022/2
1
020
202
1
2
2
1
0020
10
00020
0
2
1
D .
560 M. Gülsu and Y. Öztürk
Then, by (8), we obtain
1))(()( Txx DXT (9)
and
1))(()( T(k)(k) xx DXT , ,...2,1,0k . (10)
Moreover it is clearly seen that the relation between the matrix )(xX and its derivative )(x(k)X is
kk) xx BXX( )()( , (11)
where
0000
0000
0200
0010
N
B .
2.1. Matrix Representation for Differential and Difference Parts Let us assume that the function )(xy and its derivatives have truncated the Chebyshev expansion of the form
N
r
krr
k mkxTaxy0
)()( .,...,2,1,0),()( (12)
The derivative of the matrix )(xT defined in (10), and the relations (11), give
1))()( Tk(k) xx (DBXT . (13)
Substituting (13) into (5) we obtain
A)(DBXAT 1)()( )()()( -Tkkk xxxy , (14)
where )(),...,(),(),()(),()( 10)0()0( xTxTxTxTxTxyxy N are first-kind Chebyshev polynomial,
Naaa ,...,, 10 are coefficients to be determined in (3). Now, the matrix representation of the
differential part is given by
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 561
m
k
Tkk xxxD
0
1)()()()( AMBXP . (15)
To obtined the matrix form of the difference part
n
s
ss xyxHxH
0
)( )()()( . (16)
We know that;
BXX )()( xx , (17)
where
0
20
110
210
000
0
2
2
200
0
1
1
2
1
10
00
2
0
1
0
0
N
N
N
N
N
N
N
N
B.
Using relation (11), we can write
BBXX k(k) xx )()( . (18)
In a similarly way as (14), we obtain
A)(DBBXAT -1-
Tsks xxxy )()()( )()( . (19)
So that, the matrix representation of the difference part become
m
k
Tss xxxH
0
1)()()()( ADBBXH . (20)
2.2. Matrix Representation for Fredholm Integral Part Let assume that ),( txFi can be expanded to univariate Chebyshev series with respect to t as
follows:
562 M. Gülsu and Y. Öztürk
N
rriri tTxftxF
0
)()(),( . (21)
Then the matrix representations of the kernel function ),( txFi is given by
)()(),( txtxF T
ii TF , (22)
where
])()()()([)( 210 xfxfxfxfx iNiiii F .
Substituting the relations (14) and (22) in the Fredholm part, we obtained
ADMDFADXXDF
ADXXDFATTFF
1111
11
)()()()()()(
)()()()()()()()(),()(
Tii
Tb
a
Ti
Tb
a
Ti
b
a
b
a
iii
xdtttx
dtttxdtttxdttytxxI
i
i
i
i
i
i
i
i
We say
i
i
b
a
Ti dttt )()( XXM ,
and
Nqpqb
abm
qpi
qpi
pqi ,...,1,0,,1
][11
M .
Hence, the matrix representation of the Fredholm integral part is given by
u
i
Ti
-ii xxI
0
11 )()()( ADMDF . (23)
2.3. Matrix Representation for Volterra Integral Part Similar to the previous section, suppose that the kernel functions ),( txK j can be expanded to
the univariate Chebyshev series with respect to t as follows:
N
rrjrj tTxktxK
0
)()(),( . (24)
Then the matrix representations of the kernel function ),( txK j become
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 563
)()(),( txtxK T
jj TK , (25)
where
])()()()([)( 210 xkxkxkxkx jNjjjj K .
Using (14) and (25), we obtain
dtttxdtttxxJ Tx
a
Tj
x
c
Tjj
sj
ADXXDKATTK 11 )()()()()()()()(
ADLDKADXXDK 1111 ))(()()()()()(
T
jjT
x
c
Tj xxdtttx
j
,
where
x
c
Tj dtttx )()()( XXL ,
and
Nqpqp
cxl
qpj
qp
pqj ,...,1,0,,1
][11
L .
So that,
v
i
Tj
-jj xxxJ
0
11 ))(()()( ADLDK . (26)
2.4. Matrix Representation of the Conditions Using the relation (14), the matrix form of the conditions defined by (2) can be written as
0,))(1
0 0
1
ij
m
ki
r
j
Tkijij
k ccc A(DBX , (27)
where
][)( 210 Nijijijijij ccccc X .
564 M. Gülsu and Y. Öztürk
3. Method of Solution We are now ready to construct the fundamental matrix equation corresponding to equation (1). For this purpose, substituting the matrix relations (15), (20), (23) and (26) into equation (1) we obtain
)())(()())(()(
)()()()()()(
0
11
0
11
0
1
0
1
xgxxxx
xxxx
v
j
Tjjj
u
i
Tiii
n
s
Tss
m
k
Tkk
ADLDKDMDF
DBBXHDBXP
(28)
For computing the Chebyshev coefficient matrix A numerically, Chebyshev collocation points defined by
NrN
rxi ,...,2,1,0),cos(1(
2
are put in the above relation (28). We obtained
)())(()())(()(
)()()()()()(
0
11
0
11
0
1
0
1
r
v
j
Trjrjj
u
i
Tririi
n
s
Tsrrs
m
k
Tkrrk
xgxxxx
xxxx
ADLDKDMDF
DBBXHDBXP
. (29)
so, the fundamental matrix equation is obtained
GADLDKDMDF
DBXBHDXBP
_____
v
j
Tjjj
u
i
Tiii
n
s
Tss
m
k
Tkk
0
________11
0
11
0
1
0
1
)()(
)()(
, (30)
where
)(000
0)(00
00)(0
000)(
2
1
0
Nk
k
k
k
k
x
x
x
x
P
P
P
P
P
,
)(000
0)(00
00)(0
000)(
2
1
0
Ns
s
s
s
s
x
x
x
x
H
H
H
H
H
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 565
)(000
0)(00
00)(0
000)(
2
1
0
Nj
j
j
j
j
x
x
x
x
K
K
K
K
K
,
1
1
1
1
1
000
000
000
000
-
-
-
-
-
D
D
D
D
D___
)(000
0)(00
00)(0
000)(
2
1
0
Nj
j
j
j
j
x
x
x
x
L
L
L
L
L
,
NNNN
N
N
N
xxx
xxx
xxx
xxx
2
22
22
12
11
02
00
1
1
1
1
X ,
)(
)(
)(
)(
2
1
0
Nxg
xg
xg
xg
G
)(
)(
)(
)(
2
1
0
Ni
i
i
i
i
x
x
x
x
F
F
F
F
F
1
1
1
1
________1
)(
)(
)(
)(
)(
T
T
T
T
T
D
D
D
D
D
.
The fundamental matrix equation (30) for equation (1) corresponds to a system for the )1( N
unknown coefficients 0a , 1a ,…, Na . Briefly we can write equation (30) as
WA=G or [ W;G ] , (31)
so that
v
j
Tjjj
u
i
Tiii
n
s
Tss
m
k
Tkkpqw
0
________11
0
11
0
1
0
1
)()(
)()(][
DLDKDMDF
DBXBHDXBPW
____
Nqp ,...,1,0, . (32)
The matrix form for conditions (2) are then
CiA = [ i ] or [Ci; i ] i=0,1,…,m-1, (33)
where
]...[)()( 10
1
0
1iNii
m
k
Tkijij
ki uuucc
DBXC .
566 M. Gülsu and Y. Öztürk
To obtain the solution of equation (1) under the conditions (2), we replace the row matrices (33) by the last m rows of the matrix (31) to get the required augmented matrix
[W*;G*]=
1,11,10,1
111110
000100
,1,0,
111110
000100
;...
...;.........
;...
;...
)(;...
...;.........
)(;...
)(;...
mNmmm
N
N
mNNmNmNmN
N
N
uuu
uuu
uuu
xgwww
xgwww
xgwww
or the corresponding matrix equation
W*A=G*. (34)
If rank (W*) = rank [W*;G*]= 1N , then we can write
A=(W*)-1G*. Thus, the coefficients Nnan ,...,1,0, , are uniquely determined by equation (34). Also we can
easily check the accuracy of the obtained solutions as follows:
Since the obtained first-kind Chebyshev polynomial expansion is an approximate solution of equation (1), when the function )(xy and its derivatives are substituted in equation (1), the
resulting equation must be satisfied approximately; that is, for ixx [-1,1] , i=0,1,2,…,
0)()()()()()(00
v
jiijj
u
iiiiiii xgxJxIxHxDxE .
4. Illustrative Examples In this section, several numerical examples are given to illustrate the accuracy and effectiveness properties of the method and all of them were performed on the computer using a program written in Maple 9. The absolute errors in Tables are the values of )()( xyxy N at selected
points.
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 567
Example4.1. Let us first consider the second order linear Fredholm-Volterra integro-delay-differential-difference equation with piecewise interval,
xx
dttydttydttxydtty
xxxxxxyxxyxyxxyxy
01
1
1
0
1
))(2))())()(
)1sin()1sin()1(2)sin()1()1()1(')()(')(''
with mixed conditions 0)0(,1)0( yy and seek the solution )(xy as a truncated first-kind Chebyshev series
N
rrr xxTaxy
0
01),()( ,
so that
,1)(,)(,1)( 210 xPxxPxP 1)(0 xH , xxH )(1 , 1),(0 txF , xtxF ),(1 ,
1),(0 txK 1),(1 txK , )1sin()1sin()1(2)sin()1()( xxxxxxg .
Then, for 5N , the collocation points are
0,5
4cos2
1
2
1,
5
3cos
2
1
2
1
5
2cos
2
1
2
1,
5cos
2
1
2
1,1
543
210
xxx
xxx
and the fundamental matrix equation of the problem is
_______1
11
11
_______1
01
001
11
111
01
00
111
110
122
11
10
)()()()(
)()()()()(
TTTT
T-
T-
TTT
DLDKDLDKDMDFDMDF
DXBBHDXBHDXBPDXBPDXPW________
. (35)
With the following matrices for conditions
1010101))(0( 1 ADX T ,
0503010)()0( 1 ADBX T ,
where
568 M. Gülsu and Y. Öztürk
100000
010000
001000
000100
000010
000001
0P,
000000
00954.00000
003454.0000
0006545.000
00009045.00
000001
1P,
100000
010000
001000
000100
000010
000001
2P
100000
010000
001000
000100
000010
000001
0H,
000000
00954.00000
003454.0000
0006545.000
00009045.00
000001
1H,
000000
500000
040000
003000
000200
000010
B
100000
510000
1041000
1063100
0543210
111111
1B ,
000001
000001
000001
000001
000001
000001
0F,
000000
000000954.0
000003454.0
000006545.0
000009045.0
000001
1F
000001
000001
000001
000001
000001
000001
0K,
000001
000001
000001
000001
000001
000001
1K
16
10
16
50
8
50
08
10
2
10
8
3
004
10
4
30
0002
10
2
1000010
000001
D
.
If these matrices are substituted in (34), we obtain the linear algebraic system and the approximate solution of the problem for 5N as
5432 005079.0045501.0004434.0503090.0000000.1)( x+x+x+x+xy .
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 569
The exact solution of this problem is )cos()( xxy . Figure 1 shows the comparison between the exact solution and the approximate different for various N Chebshev collocation method solution of the system. In Table 1, we show that when N is increasing, eN is decreasing.
Table 1: Numerical solution of Example 4.1 for different N .
Figure 1. Error function of Example 4.1 for various N
Example 4.2. Let us consider the second order linear Fredholm-Volterra integro delay differential-difference equation with piecewise intervals,
x
dttxydttytxdttytx
xxxxxxyxyxyxxxyxyx
0
1
0
0
1
2342
)()()()()(
3
13
2
23176
3
2)5.0(')5.0()()1()(')(''
570 M. Gülsu and Y. Öztürk
with conditions 5)0( y , 4)0(' y and its exact solution is 542)( 2 xxxy . We obtained the approximate solution of the problem for 5N which are the same with the exact solution.
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 571
Example 4.3. Consider the second order linear Fredholm-Volterra integro delay differential-difference equation with piecewise intervals,
1
0 5.0 5.01
1
1
5.0
5.0111
)()()()()()()()(1
)5.1(
)5.0()3()1()1()1('')1('''''x xx
xx
xxxxxx
dttytxdttytxdttytxdttyedttyee
ex
exeeeexxyxxyyyeyey
with mixed conditions 1)0( y , 1)0(' y , 1)0('' y and its exact solution is xexy )( . We obtain the approximate solution of the problem for 4N , 5N , 6N which are tabulated and graphed in Table 2 and Figure 2 respectively.
Table 2: Numerical solution of Example 4.3 for different N
Figure 2. Error function of Example 4.3 for various N
572 M. Gülsu and Y. Öztürk
Example 4.4. Consider the linear third order Fredholm-Volterra integro delay differential-difference equation,
0
1 10
1
0
6543
)()()()()(
5
1
5
1
3
1
3
157
15
206
20
293)1(')1('')()1()('12)(''')1(
xx
dttxydttydttytxdtty
xxxxxxyxyxyxxyxyx
with conditions 0)0( y , 0)0(' y , 2)0('' y and its exact solution is 42)( xxxy . We obtained the approximate solution of the problem for N = 5 which are the same with the exact solution. Example 4.5. Consider the first order linear Fredholm-Volterra integro-differential equation,
1
0 0
)()('x
x dttydttyeeyy
with nonlocal boundary condition
edttyy 1
0
)()0(
and its exact solution is xexy )( . We obtain the approximate solution of the problem for 4N , 5N , 6N which are tabulated and graphed in Table 3 and Figure 3 respectively.
Table 3: Numerical solution of Example 4.5 for different N
AAM: Intern. J., Vol. 7, Issue 2 (December 2012) 573
Figure 3. Error function of Example 4.5 for various N
5. Conclusion The Chebyshev collocation methods are used to solve the linear integrodifferential- difference equation numerically. A considerable advantage of the method is that the Chebyshev polynomial coefficients of the solution are found very easily by using computer programs. Shorter computation time and lower operation count results in reduction of cumulative truncation errors and improvement of overall accuracy. Illustrative examples are included to demonstrate the validity and applicability of the technique and performed on the computer using a program written in Maple 9. To get the best approximating solution of the equation, we take more forms from the Chebyshev expansion of functions, with, the truncation limit N chosen large enough. In addition, an interesting feature of this method is finding the analytical solutions if the equation has an exact solution that is a polynomial function. Illustrative examples with the satisfactory results are used to demonstrate the application of this method. Suggested approximations make this method very attractive and contribute to the good agreement between approximate and exact values in the numerical example.
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574 M. Gülsu and Y. Öztürk
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