| // 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 testlapack |
| |
| import ( |
| "math" |
| "testing" |
| |
| "golang.org/x/exp/rand" |
| |
| "gonum.org/v1/gonum/lapack" |
| ) |
| |
| type Dlanster interface { |
| Dlanst(norm lapack.MatrixNorm, n int, d, e []float64) float64 |
| Dlanger |
| } |
| |
| func DlanstTest(t *testing.T, impl Dlanster) { |
| rnd := rand.New(rand.NewSource(1)) |
| for _, norm := range []lapack.MatrixNorm{lapack.MaxAbs, lapack.MaxColumnSum, lapack.MaxRowSum, lapack.Frobenius} { |
| for _, n := range []int{1, 3, 10, 100} { |
| for cas := 0; cas < 100; cas++ { |
| // Generate randomly the main diagonal of the |
| // symmetric tridiagonal matrix A. |
| d := make([]float64, n) |
| for i := range d { |
| d[i] = rnd.NormFloat64() |
| } |
| // Generate randomly the off-diagonal of A. |
| e := make([]float64, n-1) |
| for i := range e { |
| e[i] = rnd.NormFloat64() |
| } |
| |
| // Create A in dense representation. |
| m := n |
| lda := n |
| a := make([]float64, m*lda) |
| for i := 0; i < n; i++ { |
| a[i*lda+i] = d[i] |
| } |
| for i := 0; i < n-1; i++ { |
| a[i*lda+i+1] = e[i] |
| a[(i+1)*lda+i] = e[i] |
| } |
| |
| work := make([]float64, n) |
| // Compute a norm of A using Dlanst. |
| syNorm := impl.Dlanst(norm, n, d, e) |
| // Compute a reference value for the norm using |
| // Dlange and the dense representation of A. |
| geNorm := impl.Dlange(norm, m, n, a, lda, work) |
| if math.Abs(syNorm-geNorm) > 1e-12 { |
| t.Errorf("Norm mismatch: norm = %v, cas = %v, n = %v. Want %v, got %v.", string(norm), cas, n, geNorm, syNorm) |
| } |
| } |
| } |
| } |
| } |