All four drivers are tested with up to 21 types of random matrices. These are nearly the same as the types of matrices used to test the nonsymmetric eigenvalue computational routines, and are given in Table 3. The only differences are that matrix types 7 and 17 are scaled by a number close to the underflow threshold (rather than its square root), types 8 and 18 are scaled by a number close to the overflow threshold, and types 20 and 21 have certain rows and columns zeroed out. The reason for these changes is to activate the automatic scaling features in the driver, and to test the balancing routine.
In addition, the condition estimation features of the expert drivers xGEEVX and xGEESX are tested by the same precomputed sets of test problems used to test their constituent pieces xTRSNA and xTRSEN.