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Cholesky decomposition: Difference between revisions
Add Swift
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4 | 9.899494937 1.624553864 1.849711005 1.392621248 |
+---------------------------------------------------------+</lang>
=={{header|Swift}}==
{{trans|Rust}}
<lang swift>func cholesky(matrix: [Double], n: Int) -> [Double] {
var res = [Double](repeating: 0, count: matrix.count)
for i in 0..<n {
for j in 0..<i+1 {
var s = 0.0
for k in 0..<j {
s += res[i * n + k] * res[j * n + k]
}
if i == j {
res[i * n + j] = (matrix[i * n + i] - s).squareRoot()
} else {
res[i * n + j] = (1.0 / res[j * n + j] * (matrix[i * n + j] - s))
}
}
}
return res
}
func printMatrix(_ matrix: [Double], n: Int) {
for i in 0..<n {
for j in 0..<n {
print(matrix[i * n + j], terminator: " ")
}
print()
}
}
let res1 = cholesky(
matrix: [25.0, 15.0, -5.0,
15.0, 18.0, 0.0,
-5.0, 0.0, 11.0],
n: 3
)
let res2 = cholesky(
matrix: [18.0, 22.0, 54.0, 42.0,
22.0, 70.0, 86.0, 62.0,
54.0, 86.0, 174.0, 134.0,
42.0, 62.0, 134.0, 106.0],
n: 4
)
printMatrix(res1, n: 3)
print()
printMatrix(res2, n: 4)</lang>
{{out}}
<pre>5.0 0.0 0.0
3.0 3.0 0.0
-1.0 1.0 3.0
4.242640687119285 0.0 0.0 0.0
5.185449728701349 6.565905201197403 0.0 0.0
12.727922061357857 3.0460384954008553 1.6497422479090704 0.0
9.899494936611667 1.624553864213788 1.8497110052313648 1.3926212476456026</pre>
=={{header|Tcl}}==
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