FISH.
Інтерполяція Лагранжа.
Beloshenko + 2007
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Program source. (FORTRAN)
Lagr.for
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program InterpLagrang
real x(100),y(100),x1(100)
real p,x_,L_
integer i,j,k,N,M
open(unit=1,file='lagr.dat',status='old')
open(unit=2,file='lagr.res',status='new')
read(1,*)N
if(N.GE.100) goto 1
read(1,*)(x(i),i=1,N)
read(1,*)(y(i),i=1,N)
read(1,*)M
if(M.GE.100) goto 1
read(1,*)(x1(i),i=1,M)
write(2,*)M
write(2,*)
do 2 i=1,M
x_=x1(i)
L_=0
do 3 j=1,N
p=1
do 4 k=1,j-1
p=p*(x_-x(k))/(x(j)-x(k))
4 continue
do 5 k=j+1,N
p=p*(x_-x(k))/(x(j)-x(k))
5 continue
L_=L_+y(j)*p
3 continue
write(2,*)L_
2 continue
1 close(2)
close(1)
stop
end
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Lagr.dat
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4
1 3 5 7
1 9 25 49
6
0 1 2 3 4 5
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Lagr.res
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6
0.000000
1.000000
4.000000
9.000000
16.00000
25.00000
FISH.