Alternative approach for solving indefinite symmetrical system of equation

In this work, an alternative approach is proposed for solving system of spa rse, symmetrical, indefinite equations. The key idea here is first to trans form the original indefinite system into a new (modified) system of symmetr ical, "definite" equations which can be conveniently used to obtain the "in termediate solution". This "intermediate" solution is then transformed back into the "original" space to obtain the "original" unknown vector. To validate the formulas developed in our paper, several NASA indefinite sy stem of equations have been solved (ranging from 51 to 15,367 indefinite eq uations) on inexpensive workstations. (C) 2000 Elsevier Science Ltd. All ri ghts reserved.