% of Iterations Per Shift Before Orthogonalization - CAESAR II - Help

CAESAR II Users Guide

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CAESAR II
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CAESAR II Version
13

Specifies the decimal equivalent of the needed percentage, as described below.

For a value of 0, CAESAR II calculates a number of iterations per shift to be performed. A maximum of N eigenpairs can conceivably converge per subspace pass, where N is the subspace size (although this is highly unlikely). By default, a Gram-Schmidt orthogonalization is performed for each subspace pass. This parameter and No. of Iterations Per Shift (0 - Pgm computed) control solution shifting by limiting the number of Gram-Schmidt orthogonalizations. For example, if 12 is the number of iterations, and this parameter is 50 percent (entered as 0.50), the Gram-Schmidt orthogonalization is performed every six iterations.

Use caution when setting these parameters. Select Y as the value for Force Orthogonalization After Convergence (Y/N) if the frequency of orthogonalization is slowed.