how to make a table of iterations
15 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
i need help to make table of iterations to this code
tic
clear; clc; close all;
syms f(x,y) ph
% f(x,y)
f(x,y)=3*x^2+y^2;
% Initial Guess:
x0=[4;4];
% Gradient Computation:
g(x,y)=[diff(f(x,y),x) ; diff(f(x,y),y)];
fprintf('========================================\n');
g0=g(x0(1),x0(2));
XX=[x0(1)];
YY=[x0(2)];
ff=[f(x0(1),x0(2))];
fprintf('Loop 1\n');
x2(ph)=x0(1)-ph*g0(1);
y2(ph)=x0(2)-ph*g0(2);
G=-g(x2(ph),y2(ph)).*g0;
G=G(1)+G(2);
phsol=solve(G,ph);
X=x0(1)-phsol*g0(1);% New x value
Y=x0(2)-phsol*g0(2);% New y value
m=(Y-x0(2))/(X-x0(1));
%error=10^-20
err=10^-20;
ii=2;
fprintf('alpha=%.3f\n',phsol);
fprintf('x=%.3f y=%.3f\n',X,Y);
fprintf('f(Xnew,Ynew)=%.3f\n',f(X,Y));
fprintf('m=%.3f\n',m);
%relative norm
relnorm=sqrt((X-x0(1))^2/x0(1)^2 + (Y-x0(2))^2/x0(2)^2 );
fprintf('relative norm=%.3f\n',relnorm);
XX=[XX X];
YY=[YY Y];
ff=[ff f(X,Y)];
fprintf('========================================\n');
while(abs(f(X,Y) - f(x0(1),x0(2))) > err)
x0=[X,Y];
g0=g(x0(1),x0(2));
fprintf('Loop%d\n',ii);
x2(ph)=x0(1)-ph*g0(1);
y2(ph)=x0(2)-ph*g0(2);
G=-g(x2(ph),y2(ph)).*g0;
G=G(1)+G(2);
phsol=solve(G,ph);
X=x0(1)-phsol*g0(1);
Y=x0(2)-phsol*g0(2);
ii=ii+1;
% Output results
fprintf('alpha=%.3f\n',phsol);
fprintf('x=%.3f y=%.3f\n',X,Y);
fprintf('f(Xnew,Ynew)=%.3f\n',f(X,Y));
% m
m=(Y-x0(2))/(X-x0(1));
fprintf('m=%.3f\n',m);
% relative norm
relnorm=sqrt((X-x0(1))^2/x0(1)^2 + (Y-x0(2))^2/x0(2)^2 );
fprintf('relative norm=%.3f\n',relnorm);
XX=[XX X];
YY=[YY Y];
ff=[ff f(X,Y)];
fprintf('========================================\n');
end
% Plot Contour
xx=linspace(-5,5);
yy=linspace(-5,5);
[xx,yy] = meshgrid(xx,yy);
ff=3*xx.^2+yy.^2;
[x,y,z] = peaks(100);
v=[0.5,1,1.5,2,2.5];
[C,h] = contour(xx,yy,ff,[-90,-80 -70 -60 -50 -40 30 -20 -10 -5 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 5 10 20 30 40 50 60 70 80 90],'lineWidth',1.5);
clabel(C,h)
hold on
plot(XX,YY,'*-r');
xlabel('X')
ylabel('Y')
hold off
xlabel ('x')
ylabel ('y')
grid
fprintf('initial guess = (4,4)\n');
fprintf('error = 10^-20\n');
fprintf('Number of iteration = %d\n',ii-1);
toc
0 Kommentare
Antworten (1)
KSSV
am 27 Apr. 2023
The vairable T at the end is the required table. If you want it as an array check the variable iwant.
tic
clear; clc; close all;
syms f(x,y) ph
count = 1 ;
iwant = zeros([],7) ;
% f(x,y)
f(x,y)=3*x^2+y^2;
% Initial Guess:
x0=[4;4];
% Gradient Computation:
g(x,y)=[diff(f(x,y),x) ; diff(f(x,y),y)];
fprintf('========================================\n');
g0=g(x0(1),x0(2));
XX=[x0(1)];
YY=[x0(2)];
ff=[f(x0(1),x0(2))];
fprintf('Loop 1\n');
x2(ph)=x0(1)-ph*g0(1);
y2(ph)=x0(2)-ph*g0(2);
G=-g(x2(ph),y2(ph)).*g0;
G=G(1)+G(2);
phsol=solve(G,ph);
X=x0(1)-phsol*g0(1);% New x value
Y=x0(2)-phsol*g0(2);% New y value
m=(Y-x0(2))/(X-x0(1));
%error=10^-20
err=10^-20;
ii=2;
fprintf('alpha=%.3f\n',phsol);
fprintf('x=%.3f y=%.3f\n',X,Y);
fprintf('f(Xnew,Ynew)=%.3f\n',f(X,Y));
fprintf('m=%.3f\n',m);
%relative norm
relnorm=sqrt((X-x0(1))^2/x0(1)^2 + (Y-x0(2))^2/x0(2)^2 );
fprintf('relative norm=%.3f\n',relnorm);
fprintf('========================================\n');
iwant(count,:) = [count phsol X Y f(X,Y) m relnorm] ;
while(abs(f(X,Y) - f(x0(1),x0(2))) > err)
count = count+1 ;
x0=[X,Y];
g0=g(x0(1),x0(2));
fprintf('Loop%d\n',ii);
x2(ph)=x0(1)-ph*g0(1);
y2(ph)=x0(2)-ph*g0(2);
G=-g(x2(ph),y2(ph)).*g0;
G=G(1)+G(2);
phsol=solve(G,ph);
X=x0(1)-phsol*g0(1);
Y=x0(2)-phsol*g0(2);
ii=ii+1;
% Output results
fprintf('alpha=%.3f\n',phsol);
fprintf('x=%.3f y=%.3f\n',X,Y);
fprintf('f(Xnew,Ynew)=%.3f\n',f(X,Y));
% m
m=(Y-x0(2))/(X-x0(1));
fprintf('m=%.3f\n',m);
% relative norm
relnorm=sqrt((X-x0(1))^2/x0(1)^2 + (Y-x0(2))^2/x0(2)^2 );
fprintf('relative norm=%.3f\n',relnorm);
% XX=[XX X];
% YY=[YY Y];
% ff=[ff f(X,Y)];
fprintf('========================================\n');
iwant(count,:) = [count phsol X Y f(X,Y) m relnorm] ;
end
% Plot Contour
xx=linspace(-5,5);
yy=linspace(-5,5);
[xx,yy] = meshgrid(xx,yy);
ff=3*xx.^2+yy.^2;
[x,y,z] = peaks(100);
v=[0.5,1,1.5,2,2.5];
[C,h] = contour(xx,yy,ff,[-90,-80 -70 -60 -50 -40 30 -20 -10 -5 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 5 10 20 30 40 50 60 70 80 90],'lineWidth',1.5);
clabel(C,h)
hold on
plot(XX,YY,'*-r');
xlabel('X')
ylabel('Y')
hold off
xlabel ('x')
ylabel ('y')
grid
fprintf('initial guess = (4,4)\n');
fprintf('error = 10^-20\n');
fprintf('Number of iteration = %d\n',ii-1);
toc
T = array2table(iwant) ;
T.Properties.VariableNames = {'Loop','alpha','x','y','f(x,y)','m','relative_norm'};
T
0 Kommentare
Siehe auch
Kategorien
Mehr zu Assembly finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!