[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Octave-bug-tracker] [bug #58558] Jacobi method .m file that runs well i
|
From: |
Baracu T. |
|
Subject: |
[Octave-bug-tracker] [bug #58558] Jacobi method .m file that runs well in Matlab but not in Octave |
|
Date: |
Sun, 14 Jun 2020 18:54:46 -0400 (EDT) |
|
User-agent: |
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:77.0) Gecko/20100101 Firefox/77.0 |
Follow-up Comment #2, bug #58558 (project octave):
OK, i made some adaption to the problem, I updated the code in order to run
directly without interogation. The code from below runs without problem in
Matlab. When I run in Octave, there appear two problems:
1) does not process the instruction "disp" from inside the code in the
following format (instead, in Matlab it works):
disp("Diag. elem."+" "+"Line sum"+" "+"DiffDiag")
2) does not process the instruction "table". It is not implemented? Im
surprised.
Due to those 2 problems, the code does not run successfully in Octave.
The updated code:
% Jacobi method (Met. Jacobi) in Matlab
clc; close all; clear all
%n=input ('Enter no. of eqs. n=');
%Aug=input('Enter elem. of the sys. row-wise (Ex. [1.1 3; 1 0;…;...]:');
%x=input('Enter init. values of the variables (default [0; 0; 0; 0] ):');
%errmax=input('Enter max. err. (default 0.001 ):');
%itmax=input('Enter max no. of it. (default 100 ):');
n=4;
Aug=[6 2 1 2 5 ; 2 5 -1 1 -16.5 ; 1 -1 5 -1 23.5 ; 2 1 -1 7 -1.5];
x=[0; 0; 0; 0];
errmax=0.001; itmax=100
fprintf('\n------The augmented matrix is:-------')
Aug %print the new pivotized matrix
sum=zeros(n,1); err=1; it = 0; % initialize a set of variables
for i=1:n % ------Pivotisation to make eqs. diag. dominant---
for k=i+1:n
if abs(Aug(i,i))<abs(Aug(k,i))
for j=1:n+1
temp=Aug(i,j);
Aug(i,j)=Aug(k,j);
Aug(k,j)=temp;
end
end
end
end
fprintf('\n----The aug. matrix after Pivotisation is:--')
Aug %print the new pivotized matrix
disp('Comparis. diag. elem. vs line sum')
disp("Diag. elem."+" "+"Line sum"+" "+"DiffDiag")
disp('---------------------------------------------------------')
for i=1:n
s=0;
for j=1:n
if j~=i
s=s+abs(Aug(i,j));
end
sum(i)=s;
DiffDiag(i)= abs(Aug(i,i))-sum(i);
AbsDiag(i)=abs(Aug(i,i));
end
end
table(AbsDiag.',sum,DiffDiag.','VariableNames',{
'AbsDiag','Linesum','DiffDiag'})
if(DiffDiag>0)
disp('Matrix diagonally dominant. Sys. Converges')
else
disp('Matrix not diag. domin. Sys. may not converge.')
end
fprintf('\n-----Perform loop iterations (new vs. old values)-----\n')
fprintf('\n-------Results of Jacobi method------\n\n')
while err>errmax & it<=itmax
it=it+1;
xold=x;
for i=1:n
rhs=Aug(i,n+1)/Aug(i,i); % rhs is the right hand side member
for j=1:n
if j~=i
rhs = rhs-1/Aug(i,i)*Aug(i,j)*xold(j);
end
end
x(i)= rhs;
err=abs(x(i)- xold(i));
tx(it,i)=x(i); % alternatively [it x(1) x(2) x(3) x(4)]
ti(it)=it;
te(it,i)=err;
end
end
if err<=errmax & it<=itmax
disp("Sys. converges after "+it+" itrs.")
else
disp("Sys. not converges after "+it+" it.")
disp("Partial values from allowed max. no. of it:");
end
table(ti(:), tx(:,1),tx(:,2),tx(:,3),tx(:,4),te(:,1),te(:,2),te(:,3),te(:,4),
'VariableNames', {'itr','x1','x2','x3', 'x4','err1','err2','err3', 'err4'})
fprintf('\nSys solution:\n %f\n %f\n %f\n %f\n\n after %d itrs.\n', x, it);
fprintf('\nSol.:\n x1=%9.5f\n x2=%9.5f\n x3=%9.5f\n x4=%9.5f\n',
x(1,:),x(2,:),x(3,:),x(4,:))
############################################
############################################
############################################
THE RESULT THAT SHOUD APPEAR:
itmax =
100
------The augmented matrix is:-------
Aug =
6.0000 2.0000 1.0000 2.0000 5.0000
2.0000 5.0000 -1.0000 1.0000 -16.5000
1.0000 -1.0000 5.0000 -1.0000 23.5000
2.0000 1.0000 -1.0000 7.0000 -1.5000
----The aug. matrix after Pivotisation is:--
Aug =
6.0000 2.0000 1.0000 2.0000 5.0000
2.0000 5.0000 -1.0000 1.0000 -16.5000
1.0000 -1.0000 5.0000 -1.0000 23.5000
2.0000 1.0000 -1.0000 7.0000 -1.5000
Comparis. diag. elem. vs line sum
Diag. elem. Line sum DiffDiag
---------------------------------------------------------
ans =
4×3 table
AbsDiag Linesum DiffDiag
_______ _______ ________
6 5 1
5 4 1
5 3 2
7 4 3
Matrix diagonally dominant. Sys. Converges
-----Perform loop iterations (new vs. old values)-----
-------Results of Jacobi method------
Sys. converges after 14 itrs.
ans =
14×9 table
itr x1 x2 x3 x4 err1 err2
err3 err4
___ _______ _______ ______ ________ _________ _________
__________ __________
1 0.83333 -3.3 4.7 -0.21429 0.83333 3.3
4.7 0.21429
2 1.2214 -2.6505 3.8305 0.69048 0.3881 0.64952
0.86952 0.90476
3 0.84825 -3.1606 4.0637 0.36259 0.37317 0.5101
0.23324 0.32789
4 1.0887 -2.8991 3.9708 0.5754 0.24046 0.2615
0.092962 0.21281
5 0.9461 -3.0564 4.0175 0.45606 0.14261 0.15734
0.04677 0.11934
6 1.0305 -2.9661 3.9907 0.52596 0.08443 0.090265
0.026813 0.069904
7 0.98161 -3.0193 4.0059 0.48511 0.048921 0.053115
0.015148 0.040848
8 1.0104 -2.9885 3.9968 0.50884 0.028797 0.030768
0.0090086 0.023729
9 0.99374 -3.0066 4.002 0.49493 0.016664 0.018066
0.00514 0.01391
10 1.0035 -2.9961 3.9989 0.50301 0.0098021 0.010476
0.0030624 0.0080764
11 0.99787 -3.0022 4.0007 0.49827 0.0056736 0.0061486
0.00175 0.0047346
12 1.0012 -2.9987 3.9996 0.50102 0.0033361 0.0035664
0.0010419 0.0027494
13 0.99928 -3.0008 4.0002 0.49941 0.0019316 0.0020927
0.00059594 0.0016115
14 1.0004 -2.9995 3.9999 0.50035 0.0011354 0.0012141
0.00035451 0.00093597
Sys solution:
1.000411
-2.999547
3.999875
0.500348
after 14 itrs.
Sol.:
x1= 1.00041
x2= -2.99955
x3= 3.99988
x4= 0.50035
_______________________________________________________
Reply to this item at:
<https://savannah.gnu.org/bugs/?58558>
_______________________________________________
Message sent via Savannah
https://savannah.gnu.org/