Identify OP and B for the Driver to be Modified

Once a driver is chosen. The next step is to identify OP and B associated with that driver. Eigenvalues of OP are computed by the computational routine znaupd. These eigenvalues are converted to those of ${\bf A}$ or in the post-processing routine zneupd. The Arnoldi vectors generated by znaupd are B-orthonormal. It is very important to construct the operation and correctly. The following list summarize the operator OP and B defined in each driver.

 

DRIVER OP B

$${\bf A}$$ zndrv1 zndrv2

$${\bf M}$$ zndrv3

$${\bf M}$$ zndrv4

Because of the reverse communication interface of ARPACK, the construction of

is left completely to the user. This means that the user is free to choose any convenient data structure for the matrix representation. If the matrix is not available, the user is free to express the action of the matrix on a vector through a subroutine call or a code segment.