Luis Portugal died on July 21, 1998 in Lisbon, Portugal, at the young
age of 34. The cause was complications following a bone marrow
transplant. Luis had been fighting a lymphoma for the past three
and a half years. Funeral services were held in Coimbra following
the international meeting "Optimization 98" held there on July 20-22.
Luis was intensely dedicated to his work, family, and friends, as well
as about the way he lived. He leaves, unfinished, his Ph.D.
dissertation (under the supervision of J. J. Júdice), his wife
Helena (Lena), and many, many friends. They all miss him very
much.
Throughout his short career, Luis made several important contributions
to his field of investigation. His research interests were
concentrated in linear and quadratic programming, network optimization,
interior-point methods, and iterative methods for linear systems.
His great ideas and his enthusiasm about research are greatly
missed. Here is his bibliography:
L. Portugal, A. Portugal and J. Júdice, "Estimação
de parâmetros cinéticos de um sistema reaccional utilizado
na preparação de resinas de melamina formaldeido em meio
butanólico," in M. Turkman and M. Carvalho (Eds.), Proceedings
of the First Portuguese Conference on Statistics and Optimization,
Troia, pp. 557-593, 1990.
L. Portugal, J. Júdice, and L. Vicente, "A comparison of block
pivoting and interior-point algorithms for linear least-squares
problems with nonnegative variables," Mathematics of Computation, vol.
63, pp. 625-643, 1994.
L. Portugal, "On the solution of least square problems," Master Thesis,
University of Coimbra, 1992 (written in Portuguese).
L. Portugal, F. Bastos, J. Júdice, J. Paixão, and T.
Terlaky, "An investigation of interior-point algorithms for the linear
transportation problem," SIAM Journal on Scientific Computing, vol. 17,
pp. 1202-1223, 1996.
L. Portugal and J. Júdice, "A hybrid algorithm for the solution
of a large-scale single commodity equilibrium model," Computers and
Operations Research, vol. 23, pp. 623-639, 1996.
L. Portugal, M. Resende, G. Veiga and J. Júdice, "A truncated
primal-infeasible dual-feasible network interior-point method,"
Networks, vol. 35, pp. 91-108, 2000.
L. Portugal, L. Fernandes and J. Júdice, "A truncated Newton
interior-point algorithm for the solution of a multicommodity spatial
equilibrium problem," in M. Ferris and J. Pang, (Eds.), Complementarity
and Variational Problems, SIAM, pp. 415-444, 1997.
J. Júdice L. Portugal, M. Resende and G. Veiga, "A truncated
Newton interior point method for the solution of the multicommodity
minimum cost network flow problem," Proceedings of the First Portuguese
Conference on Telecommunications, Aveiro, Portugal, pp. 381-384, 1997
(written in Portuguese).
J. Júdice, J. Patrício, L. Portugal, M. Resende, and G.
Veiga, "A study of preconditioners for network interior point methods,"
Computational Optimization and Applications, vol. 24, pp. 5-35, 2003.
J. Patrício, L. Portugal, M. Resende, G. Veiga, and J.
Júdice, "Fortran subroutines for network flow optimization
using an interior point algorithm, AT&T Labs Research
Technical Report TD-5X2SLN, Florham Park, March 2004.
