Wrong results from ScaLAPACK routines are most often caused by incorrect usage. It is also possible that wrong results are caused by a bug outside of ScaLAPACK, in the compiler or in one of the library routines, such as the BLAS, the BLACS, or the underlying message-passing layer, that are linked with ScaLAPACK. Test suites are available for ScaLAPACK, the PBLAS, the BLACS, and the BLAS. The ScaLAPACK installation guide  or the BLACS installation guide should be consulted for descriptions of the tests and for advice on resolving problems.
A list of known problems, compiler errors, and bugs in ScaLAPACK routines is maintained on netlib; see Chapter 1.
Users who suspect they have found a new bug in a ScaLAPACK routine are encouraged to report it promptly to the developers as directed in Chapter 1. The bug report should include a test case, a description of the problem and expected results, and the actions, if any, that the user has already taken to fix the bug.