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 // Copyright ©2016 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 stat_test import ( "fmt" "gonum.org/v1/gonum/mat" "gonum.org/v1/gonum/stat" ) func ExamplePC() { // iris is a truncated sample of the Fisher's Iris dataset. n := 10 d := 4 iris := mat.NewDense(n, d, []float64{ 5.1, 3.5, 1.4, 0.2, 4.9, 3.0, 1.4, 0.2, 4.7, 3.2, 1.3, 0.2, 4.6, 3.1, 1.5, 0.2, 5.0, 3.6, 1.4, 0.2, 5.4, 3.9, 1.7, 0.4, 4.6, 3.4, 1.4, 0.3, 5.0, 3.4, 1.5, 0.2, 4.4, 2.9, 1.4, 0.2, 4.9, 3.1, 1.5, 0.1, }) // Calculate the principal component direction vectors // and variances. var pc stat.PC ok := pc.PrincipalComponents(iris, nil) if !ok { return } fmt.Printf("variances = %.4f\n\n", pc.VarsTo(nil)) // Project the data onto the first 2 principal components. k := 2 var proj mat.Dense proj.Mul(iris, pc.VectorsTo(nil).Slice(0, d, 0, k)) fmt.Printf("proj = %.4f", mat.Formatted(&proj, mat.Prefix(" "))) // Output: // variances = [0.1666 0.0207 0.0079 0.0019] // // proj = ⎡-6.1686 1.4659⎤ // ⎢-5.6767 1.6459⎥ // ⎢-5.6699 1.3642⎥ // ⎢-5.5643 1.3816⎥ // ⎢-6.1734 1.3309⎥ // ⎢-6.7278 1.4021⎥ // ⎢-5.7743 1.1498⎥ // ⎢-6.0466 1.4714⎥ // ⎢-5.2709 1.3570⎥ // ⎣-5.7533 1.6207⎦ }