Sparse1.4 is a flexible package of subroutines written in C used to quickly and accurately solve large sparse systems of linear equations. The package is able to handle arbitrary real and complex square matrix equations. Besides being able to solve linear systems, it is also able to quickly solve transposed systems, find determinants, and estimate errors due to ill-conditioning in the system of equations and instability in the computations. Sparse also provides a test program that is able read matrix equations from a file, solve them, and print useful information about the equation and its solution.

Sparse1.4 is efficient when solving many matrices of similar structure. Sparse does not require or assume symmetry and is able to perform numerical pivoting to avoid unnecessary error in the solution. It handles its own memory allocation, which allows the user to forgo the hassle of providing adequate memory. It also has a natural, flexible, and efficient interface to the calling program.

Sparse was originally written for use in circuit simulators and is particularly adept at handling node- and modified-node admittance matrices. The systems of linear generated in a circuit simulator stem from solving large systems of nonlinear equations using Newton's method and integrating large stiff systems of ordinary differential equations. However, Sparse is also suitable for other uses.

The Sparse1.4 package was written in the C programming language by Kenneth Kundert. It is an open source version of Sparse1.3.
Contact the author at kundert@users.sourceforge.net.