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<%@ language=vbscript %>
<%
几个参考点的数据已经给出，输入参数只有 x
function view(result,inputx) 输出结果，同时如果<1 and >0,就在前面补0
if result<1 and result>0 then result=0&result
response.write "计算结果："&"<br>"
response.write "f("&inputx&")="& result
end function
********分段线性lagrange插值**********
function lagrange1(inputx)
dim k,i
dim x,y
x=array("0.1","0.2","0.3","0.4")
y=array("0.0998","0.1987","0.2955","0.3894")
if inputx<x(0) then k=0
if inputx>x(3) then k=2
for i=0 to 2
if inputx>=x(i) and inputx<=x(i+1) then k=i
result=((inputx-x(k+1))/(x(k)-x(k+1)))*y(k) + ((inputx-x(k))/(x(k+1)-x(k)))*y(k+1)
next
result= view(result,inputx)
end function
********分段三点二次lagrange插值**********
function lagrange2(inputx)
dim i,j,k,t
dim x,y
result=0
x=array("0.1","0.2","0.3","0.4")
y=array("0.0998","0.1987","0.2955","0.3894")
if inputx<=x(1) then k=0
if inputx>=x(2) then k=1
if inputx>x(1) and inputx<x(2) and abs(inputx-x(1))<=abs(inputx-x(2)) then k=0 else k=1
for j=k to k+2
t=1
for i= k to k+2
if i<>j then
t= t * (inputx-x(i))/(x(j)-x(i))
end if
next
result = result + t*y(j)
next
result= view(result,inputx)
end function
**********一元n点拉格朗日插值***********
function lagrange3(inputx)
dim i,j
dim x,y
result=0
x=array("0","0.1","0.195","0.4","0.401","0.5")
y=array("0.39894","0.39695","0.39142","0.38138","0.36812","0.35206")
for j=0 to 5
t=1
for i=0 to 5
if i<>j then
t= t * (inputx-x(i))/(x(j)-x(i))
end if
next
result = result + t * y(j)
next
result= view(result,inputx)
end function
***********牛顿（newton）插值***********
function newton(inputx)
dim x,y
dim i,j
result=0.39894
t=1
x=array("0","0.1","0.195","0.3","0.401","0.5")
y=array("0.39894","0.39695","0.39142","0.38138","0.36812","0.35206")
for j=1 to 5
t=t*(inputx – x(j-1))
for i=0 to 5-j
y(i)=(y(i+1) – y(i)) / (x(i+j) – x(i))
next
result = result + t * y(0)
next
result= view(result,inputx)
end function
***********埃特金（aitken）插值***********
function aitken(inputx)
dim i,j
dim x,y
x=array("0.5","0.65","0.8","1.0")
y=array("0.4794","0.6052","0.7174","0.8415")
for j=1 to 3
for i=j to 3
y(i)=y(j-1) + (y(i)-y(j-1)) / (x(i)-x(j-1))* (inputx-x(j-1))
next
next
result= view(y(3),inputx)
end function
***********分段两点三次埃（厄）尔米特（hermit）插值***********
function hermit(inputx)
dim i,k
dim x,y,yy
x=array("0.1","0.3","0.5")
y=array("0.099833","0.295520","0.479426")
yy=array("0.995004","0.995336","0.877583")
if inputx<=x(0) then k=0
if inputx>=x(2) then k=1
for i=0 to 1
if x(i)<=inputx and inputx<=x(i+1) then k=i
next
hx1=(1+2*(inputx-x(k)) / (x(k+1)-x(k))) * mul((x(k+1)-inputx) / (x(k+1)-x(k)))
hx2=(1+2*(x(k+1)-inputx) / (x(k+1)-x(k))) * mul((inputx-x(k)) / (x(k+1)-x(k)))
hx3=(inputx – x(k))* mul((x(k+1)-inputx)/(x(k+1)-x(k)))
hx4=(inputx – x(k+1))* mul((inputx-x(k))/(x(k+1)-x(k)))
result=y(k)*hx1 + y(k+1)*hx2 + yy(k)*hx3 + yy(k+1)*hx4
result= view(result,inputx)
end function
function mul(str)
mul=str*str
end function
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