github.com/gopherd/gonum@v0.0.4/mat/symmetric_example_test.go (about)

     1  // Copyright ©2015 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package mat_test
     6  
     7  import (
     8  	"fmt"
     9  
    10  	"github.com/gopherd/gonum/mat"
    11  )
    12  
    13  func ExampleSymDense_SubsetSym() {
    14  	n := 5
    15  	s := mat.NewSymDense(5, nil)
    16  	count := 1.0
    17  	for i := 0; i < n; i++ {
    18  		for j := i; j < n; j++ {
    19  			s.SetSym(i, j, count)
    20  			count++
    21  		}
    22  	}
    23  	fmt.Println("Original matrix:")
    24  	fmt.Printf("%0.4v\n\n", mat.Formatted(s))
    25  
    26  	// Take the subset {0, 2, 4}
    27  	var sub mat.SymDense
    28  	sub.SubsetSym(s, []int{0, 2, 4})
    29  	fmt.Println("Subset {0, 2, 4}")
    30  	fmt.Printf("%0.4v\n\n", mat.Formatted(&sub))
    31  
    32  	// Take the subset {0, 0, 4}
    33  	sub.SubsetSym(s, []int{0, 0, 4})
    34  	fmt.Println("Subset {0, 0, 4}")
    35  	fmt.Printf("%0.4v\n\n", mat.Formatted(&sub))
    36  
    37  	// Output:
    38  	// Original matrix:
    39  	// ⎡ 1   2   3   4   5⎤
    40  	// ⎢ 2   6   7   8   9⎥
    41  	// ⎢ 3   7  10  11  12⎥
    42  	// ⎢ 4   8  11  13  14⎥
    43  	// ⎣ 5   9  12  14  15⎦
    44  	//
    45  	// Subset {0, 2, 4}
    46  	// ⎡ 1   3   5⎤
    47  	// ⎢ 3  10  12⎥
    48  	// ⎣ 5  12  15⎦
    49  	//
    50  	// Subset {0, 0, 4}
    51  	// ⎡ 1   1   5⎤
    52  	// ⎢ 1   1   5⎥
    53  	// ⎣ 5   5  15⎦
    54  }