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## Linear Equations

Two types of driver routines are provided for solving systems of linear equations:
• the simple driver (name ending -SV) solves the system by factorizing and overwriting with the solution ;
• the expert driver (name ending -SVX) can also perform the following functions:
• solve or (unless is symmetric or Hermitian);
• estimate the condition number of , check for near-singularity, and check for pivot growth;
• refine the solution and compute forward and backward error bounds;
• equilibrate the system if is poorly scaled.

The expert driver requires roughly twice as much storage as the simple driver.
Both types of driver routines handle single or multiple right hand sides by allowing to be a vector or matrix, respectively.
Different driver routines are provided to take advantage of special properties or storage schemes of the matrix , as shown in Table 2.2.

 Type of matrix Simple Expert and storage scheme driver driver General dense LA_GESV LA_GESVX Real / complex General band LA_GBSV LA_GBSVX Real / complex General tridiagonal LA_GTSV LA_GTSVX Real / complex Positive definite full storage LA_POSV LA_POSVX Real symmetric / complex Hermitian Positive definite packed storage LA_PPSV LA_PPSVX Real symmetric / complex Hermitian Positive definite band storage LA_PBSV LA_PBSVX Real symmetric / complex Hermitian Positive definite tridiagonal LA_PTSV LA_PTSVX Real symmetric / complex Hermitian Indefinite full storage LA_SYSV / LA_SYSVX / Real symmetric / complex LA_HESV LA_HESVX symmetric / complex Hermitian Indefinite packed storage LA_SPSV / LA_SPSVX / Real symmetric / complex LA_HPSV LA_HPSVX symmetric / complex Hermitian

Next: Linear Least Squares (LLS) Up: Driver Routines Previous: Driver Routines   Contents   Index
Susan Blackford 2001-08-19