Subject: Paper review C507 From: Renato Ferreira Date: Mon, 18 Jun 2001 11:00:22 -0400 (EDT) To: gcf@cs.fsu.edu Paper and Referee Metadata Paper Number: C507 Date: 06/15/2001 Paper Title: Parallel Multilevel Iterative Linear Solvers with Unstructured Adaptive Grids for Simulations in Earth Science. Author: Kengo Nakajima Referee: Renato Ferreira Address: Computer Science Department University of Maryland, College Park. College Park, MD 20742 Referee Comments (For Editor Only) This paper was a little confusing to me. It may be due to my limited familiarity with the subject of the paper. Still I think it was an interesting paper, worthy of being published provided some reviewing of the text and reformatting. Referee Coments (For Author and Editor) The paper presents experimental results for solving Poisson equations using a multigrid preconditioned conjugate gradient iterative method (MGCG). It compares this method, proposed by the author, with Incomplete Cholesky Conjugate Gradient. The subject of the paper is relevant to the journal. There is a reasonable amount of experiments and it shows good results. However, I think that description of the algorithm proposed by the author is not very good. The description is too high level. In some occasions the paper just presents a picture (with very little associated explanation) and the reader has to figure it out by himself. In other instances, the description is too short, assuming the reader's familiarity with the subject. Due to the multidisciplinar nature of the subject, I would suggest more detailed descriptions of the algorithms. I suspect a person reading the paper will want to know more about how to implement MGCG than just how it performs compared to ICCG. I would recommend an extended version of this paper for publication. If space is a limitation here, I think the figures can be scaled down to at least half of its current size, without compromising readability. Presentation Changes The description of the algorithm proposed by the author need to be worked. I think a lot of text should be added to give the reader a more clear view of how to implement MGCG. Some formatting would do a great deal for this paper. Having the pictures closer to where they are referred to in the text simplifies the reading a lot. Presentation Changes Some words should be changed to make the sentences more readable. Last paragraph in Section 2 (Multigrid Method: Overview) should be made more specific and readable. I am not very clear what it says.