40 lines
784 B
Go
40 lines
784 B
Go
package main
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import (
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"fmt"
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"github.com/gonum/matrix/mat64"
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)
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var (
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x = []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
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y = []float64{1, 6, 17, 34, 57, 86, 121, 162, 209, 262, 321}
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degree = 2
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)
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func main() {
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a := Vandermonde(x, degree)
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b := mat64.NewDense(len(y), 1, y)
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c := mat64.NewDense(degree+1, 1, nil)
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qr := new(mat64.QR)
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qr.Factorize(a)
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err := c.SolveQR(qr, false, b)
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if err != nil {
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fmt.Println(err)
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} else {
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fmt.Printf("%.3f\n", mat64.Formatted(c))
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}
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}
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func Vandermonde(a []float64, degree int) *mat64.Dense {
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x := mat64.NewDense(len(a), degree+1, nil)
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for i := range a {
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for j, p := 0, 1.; j <= degree; j, p = j+1, p*a[i] {
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x.Set(i, j, p)
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}
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}
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return x
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}
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