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// Copyright ©2022 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package mat_test
import (
"fmt"
"log"
"gonum.org/v1/gonum/mat"
)
func ExampleQR_solveTo() {
// QR factorization can be used for solving linear inverse problems,
// as this is a more numerically stable technique than direct
// matrix inversion.
//
// Here, we want to solve:
// Ax = b
var (
a = mat.NewDense(4, 2, []float64{0, 1, 1, 1, 1, 1, 2, 1})
b = mat.NewDense(4, 1, []float64{1, 0, 2, 1})
x = mat.NewDense(2, 1, nil)
)
var qr mat.QR
qr.Factorize(a)
err := qr.SolveTo(x, false, b)
if err != nil {
log.Fatalf("could not solve QR: %+v", err)
}
fmt.Printf("%.3f\n", mat.Formatted(x))
// Output:
// ⎡0.000⎤
// ⎣1.000⎦
}
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