code: function cross(A, B) {
      if (A.shape.length !== 1 || B.shape.length !== 1) {
          throw new Error('A or B is not 1D');
      }
      if (A.length < 3 || B.length < 3) {
          throw new Error('A or B is less than 3 in length');
      }
      var a1 = A.getN(0);
      var a2 = A.getN(1);
      var a3 = A.getN(2);
      var b1 = B.getN(0);
      var b2 = B.getN(1);
      var b3 = B.getN(2);
      return new ndarray_1.NDArray([
          a2 * b3 - a3 * b2,
          a3 * b1 - a1 * b3,
          a1 * b2 - a2 * b1
      ]);
  }
docs: Computes cross product of A and B
  Only defined for A and B to 1D vectors of length at least 3
  Only first 3 elements of A and B are used