Gaussian elimination: Difference between revisions

</pre>

=={{header|Phix}}==

{{trans|PHP}}

<lang Phix>function gauss_eliminate(sequence a, b)

integer n = length(b)

atom tmp

for col=1 to n do

integer m = col

atom mx = a[m][m]

for i=col+1 to n do

tmp = abs(a[i][col])

if tmp>mx then

{m,mx} = {i,tmp}

end if

end for

if col!=m then

{a[col],a[m]} = {a[m],a[col]}

{b[col],b[m]} = {b[m],b[col]}

end if

for i=col+1 to n do

tmp = a[i][col]/a[col][col]

for j=col+1 to n do

a[i][j] -= tmp*a[col][j]

end for

a[i][col] = 0

b[i] -= tmp*b[col]

end for

end for

sequence x = repeat(0,n)

for col=n to 1 by -1 do

tmp = b[col]

for j=n to col+1 by -1 do

tmp -= x[j]*a[col][j]

end for

x[col] = tmp/a[col][col]

end for

return x

end function

constant a = {{1.00, 0.00, 0.00, 0.00, 0.00, 0.00},

{1.00, 0.63, 0.39, 0.25, 0.16, 0.10},

{1.00, 1.26, 1.58, 1.98, 2.49, 3.13},

{1.00, 1.88, 3.55, 6.70, 12.62, 23.80},

{1.00, 2.51, 6.32, 15.88, 39.90, 100.28},

{1.00, 3.14, 9.87, 31.01, 97.41, 306.02}},

b = {-0.01, 0.61, 0.91, 0.99, 0.60, 0.02}

pp(gauss_eliminate(a, b))</lang>

{{out}}

<pre>

{-0.01,1.602790395,-1.61320306,1.245494121,-0.4909897196,0.06576069618}