Modify problem dependent variables

  These variables include the following

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• [n] The dimension of the problem.
• [nev] The number of eigenvalues needed.
• [ncv] The length of the Arnoldi factorization.
• [which] Part of the spectrum that is of interest.
• [sigma] Real shift used in dsbdr2 and dsbdr4, or complex shift used in znbdr2 and znbdr4.
• [sigmar] The real part of the shift used in a real nonsymmetric shift invert mode driver (dnbdr2, dnbdr4, dnbdr5, dnbdr6.)
• [sigmai] The imaginary part of the shift used in a real nonsymmetric shift invert mode driver (dnbdr5, dnbdr6). It should be set to zero in dnbdr2 and dndrv4.