public void ShouldExtractMatrix2()
{
//Arrange
var matrix = new DenseMatrix(new double[,] { { 1, 2, 3 }, { 4, 5, 6 }, { 7, 8, 9 } });
//Act
var extracted = matrix.Extract(new[] { 1 }, new[] { 2 });
//Assert
AreEqual(1, extracted.ColumnCount);
AreEqual(1, extracted.RowCount);
AreEqual(new[] { 6.0 }, extracted.Row(0));
}