3 kod (26.04.2013 13:15)

0

clear all
E=0.05
x1=1;
x3=4;
m=0.5; %shag
x2=x1+m
fx1=fun(x1)
fx2=fun(x2)
fla=1

if fx1>fx2
x3=x1+2*m
else
if fx1<fx2
x3=x1-m
end
end

while fla=1

fx3=fun(x3)
if fx1< fx2 & fx1 <fx3
xmin=x1;
fmin=fx1;
else
if fx2<fx1 & fx2<fx3
xmin=x2;
fmin=fx2;
else
xmin=x3;
fmin=fx3;
end
end
a1=(fx2-fx1)/(x2-x1)
a2=1/(x3-x2)*((fx3-fx1)/(x3-x1)-a1)
xopt=(x2+x1)/2-(a1/2*a2)
provA=fmin-fun(xopt)
provB=xmin-xopt

if provA < E & provB < E
fla=0;
break
end

if fun(xmin) < fun(xopt)
fx1=fun(xmin)
else
fx1=fun(xopt)
end

fx2

end

2 Владимир (25.04.2013 11:30)

0

clear all
x=-2:0.01:2;
y=x.^4 - x.^3-2*x.^2+3*x-3;
plot(x,y)
grid on

1 Anton (18.04.2013 10:03)

0

function [X,k]=iter(A,B,E)
n=length(B);
for i=1 : n
t=0;
for j=1 : n
if (i~=j)
t = t + abs(A(i,j));
end
end
if abs(A(i,i)) <= t
'trouble'
end
end

X = B;
f = 1;
k=0;
while f == 1
X1 = X;
f = 0;
k=k+1;
for i=1 : n
c=0;
for j=1 : n
if (i~=j)
c = c + (A(i,j)*X(j))/A(i,i);
end
end
X(i) = (B(i)/A(i,i)) - c;
if (abs(X(i)-X1(i))>E)
f = 1;
end
end
end