func randMat(m, n int) *mat.Mat {
// Random symmetric positive definite matrix.
a := mat.New(m, n)
for i := 0; i < m; i++ {
for j := 0; j < n; j++ {
a.Set(i, j, rand.NormFloat64())
}
}
return a
}
// Extracts the imaginary part of a complex matrix.
func Imag(a Const) *mat.Mat {
m, n := a.Dims()
b := mat.New(m, n)
for i := 0; i < m; i++ {
for j := 0; j < n; j++ {
b.Set(i, j, imag(a.At(i, j)))
}
}
return b
}