Subspace Size (0-Not Used) - CAESAR II - Help

CAESAR II Users Guide

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CAESAR II
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CAESAR II Version
13

Specifies the subspace size as described below. The default value is 0 and usually does not need to be changed. The software then selects an expected optimal subspace size.

The eigensolution reduces the NDOFxNDOF problem to an NxN problem during each subspace iteration, where N is the subspace size.

For the default value of 0, CAESAR II uses the square root of the bandwidth as the subspace size, with a minimum of 4, resulting in sizes of 4 to 8 for typical piping configurations. Increasing the subspace size slows the eigensolution but increases the numerical stability. Values in the range between 12 and 15 are appropriate when unusual geometries or dynamic properties are encountered, or when a job is large (having 100 elements or more, and/or requires that 25 or more frequencies be extracted).