56 lines
1.2 KiB
Swift
56 lines
1.2 KiB
Swift
func gaussEliminate(_ sys: [[Double]]) -> [Double]? {
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var system = sys
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let size = system.count
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for i in 0..<size-1 where system[i][i] != 0 {
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for j in i..<size-1 {
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let factor = system[j + 1][i] / system[i][i]
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for k in i..<size+1 {
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system[j + 1][k] -= factor * system[i][k]
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}
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}
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}
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for i in (1..<size).reversed() where system[i][i] != 0 {
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for j in (1..<i+1).reversed() {
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let factor = system[j - 1][i] / system[i][i]
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for k in (0..<size+1).reversed() {
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system[j - 1][k] -= factor * system[i][k]
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}
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}
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}
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var solutions = [Double]()
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for i in 0..<size {
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guard system[i][i] != 0 else {
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return nil
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}
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system[i][size] /= system[i][i]
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system[i][i] = 1
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solutions.append(system[i][size])
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}
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return solutions
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}
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let sys = [
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[1.00, 0.00, 0.00, 0.00, 0.00, 0.00, -0.01],
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[1.00, 0.63, 0.39, 0.25, 0.16, 0.10, 0.61],
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[1.00, 1.26, 1.58, 1.98, 2.49, 3.13, 0.91],
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[1.00, 1.88, 3.55, 6.70, 12.62, 23.80, 0.99],
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[1.00, 2.51, 6.32, 15.88, 39.90, 100.28, 0.60],
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[1.00, 3.14, 9.87, 31.01, 97.41, 306.02, 0.02]
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]
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guard let sols = gaussEliminate(sys) else {
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fatalError("No solutions")
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}
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for (i, f) in sols.enumerated() {
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print("X\(i + 1) = \(f)")
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}
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