**A fast adaptive grid scheme for elliptic partial differential equations**

Calvin J. Ribbens

Pages: 179-197

DOI: 10.1145/66888.66889

We describe the Recursive Subdivision (RS) method-an efficient and effective adaptive grid scheme for two-dimensional elliptic partial differential equations (PDEs). The RS method generates a new grid by recursively subdividing a rectangular...

**A graph partitioning algorithm by node separators**

Joseph W. H. Liu

Pages: 198-219

DOI: 10.1145/66888.66890

A heuristic graph partitioning scheme is presented to determine effective node separators for undirected graphs. An initial separator is first obtained from the minimum degree ordering, an algorithm designed originally to produce fill-reducing...

**Constrained nonlinear least squares: an exact penalty approach with projected structured quasi-Newton updates**

Nezam Mahdavi-Amiri, Richard H. Bartels

Pages: 220-242

DOI: 10.1145/66888.66891

This paper is concerned with the development, numerical implementation, and testing of an algorithm for solving constrained nonlinear least squares problems. The algorithm is an adaptation of the least squares case of an exact penalty method for...

**Algorithm 675: Fortran subroutines for computing the square root covariance filter and square root information filter in dense or Hessenberg forms**

M. Vanbegin, M. Verhaegen

Pages: 243-256

DOI: 10.1145/66888.69647

In this paper, codes are provided for two of the most popular square root filters: the Square Root Covariance Filter and the Square Root Information Filter. We also give efficient implementations for the time invariant case based on so-called...

**Remark on algorithm 587**

V. Dadurkevicius

Pages: 257-261

DOI: 10.1145/66888.77344

The subroutine WNNLS of Algorithm 587 has exposed some shortcomings, especially in solving rank-deficient problems. They may lead to fatal errors and (or) false results. Five improvements are proposed. The effect of the changes is tested on four...

**Remark on algorithm 630**

A. Buckley

Pages: 262-274

DOI: 10.1145/66888.69648

**Residual hermite normal form computations**

Paul D. Domich

Pages: 275-286

DOI: 10.1145/66888.66892

This paper extends the class of Hermite normal form solution procedures that use modulo determinant arithmetic. Given any relatively prime factorization of the determinant value, integral congruence relations are used to compute the Hermite...

**Corrigenda: “Two FORTRAN Packages for Assessing Initial Value Methods”**

W. H. Enright, J. D. Pryce

Page: 287

DOI: 10.1145/66888.356282

**Corrigenda: “An Efficient Derivative-Free Method for Solving Nonlinear Equations”**

D. Le

Page: 287

DOI: 10.1145/66888.356283

**Corrigenda: “Minimizing Multimodal Functions of Continuous Variables with the ‘Simulated Annealing’ Algorithm”: **

A. Corana,

M. and C. Martini and S. Ridella
Page: 287

DOI: 10.1145/66888.356281