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Gaussian elimination: Difference between revisions
Add Swift
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3 | .0638888889 -.1444444444 .1472222222 |
+----------------------------------------------+</lang>
=={{header|Swift}}==
{{trans|Rust}}
<lang swift>func gaussEliminate(_ sys: [[Double]]) -> [Double]? {
var system = sys
let size = system.count
for i in 0..<size-1 where system[i][i] != 0 {
for j in i..<size-1 {
let factor = system[j + 1][i] / system[i][i]
for k in i..<size+1 {
system[j + 1][k] -= factor * system[i][k]
}
}
}
for i in (1..<size).reversed() where system[i][i] != 0 {
for j in (1..<i+1).reversed() {
let factor = system[j - 1][i] / system[i][i]
for k in (0..<size+1).reversed() {
system[j - 1][k] -= factor * system[i][k]
}
}
}
var solutions = [Double]()
for i in 0..<size {
guard system[i][i] != 0 else {
return nil
}
system[i][size] /= system[i][i]
system[i][i] = 1
solutions.append(system[i][size])
}
return solutions
}
let sys = [
[1.00, 0.00, 0.00, 0.00, 0.00, 0.00, -0.01],
[1.00, 0.63, 0.39, 0.25, 0.16, 0.10, 0.61],
[1.00, 1.26, 1.58, 1.98, 2.49, 3.13, 0.91],
[1.00, 1.88, 3.55, 6.70, 12.62, 23.80, 0.99],
[1.00, 2.51, 6.32, 15.88, 39.90, 100.28, 0.60],
[1.00, 3.14, 9.87, 31.01, 97.41, 306.02, 0.02]
]
guard let sols = gaussEliminate(sys) else {
fatalError("No solutions")
}
for (i, f) in sols.enumerated() {
print("X\(i + 1) = \(f)")
}</lang>
{{out}}
<pre>X1 = -0.01
X2 = 1.6027903945021138
X3 = -1.613203059905563
X4 = 1.245494121371438
X5 = -0.4909897195846575
X6 = 0.065760696175232</pre>
=={{header|Tcl}}==
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