[Trilinos-Users] BlockKrylovSchur: number of required Ritz vectors splits a complex conjugate pair.

Michael Junge junge at iam.uni-stuttgart.de
Tue Nov 25 10:48:15 MST 2008

when running the Block Krylov Schur solver of the trilinos package 8.0.3 
for an unsymmetric eigenvalue problem, I get the error message
"Anasazi::BlockKrylovSchur::computeRitzVectors(): the number of required 
Ritz vectors splits a complex conjugate pair."
after the 6-th iteration.
Is there any possibility to cope with this error? Can I instead of 
throwing this exception
lower the variable numRitzVecs_ by one and proceed without any 
subsequent error?
Any suggestions to resolve this error are greatly appreciated.



                         BlockKrylovSchur Solver Status

The solver is initialized.
The number of iterations performed is 6
The block size is         12
The number of blocks is   7
The current basis size is 72
The number of auxiliary vectors is    0
The number of operations Op*x   is 72

              Ritz Value                 Ritz Residual
   9.565366e-05 + i   0.000000e+00        5.162558e-14
   6.535990e-05 + i   0.000000e+00        3.367828e-13
   1.531108e-05 + i   0.000000e+00        3.643859e-11
   1.074612e-05 + i   0.000000e+00        7.339283e-10
   6.653571e-06 + i   0.000000e+00        3.781330e-09
   5.151594e-06 + i   0.000000e+00        1.167965e-08
   4.963956e-06 + i   0.000000e+00        4.357004e-09
   4.831631e-06 + i   0.000000e+00        9.323526e-09
   4.176412e-06 + i   0.000000e+00        1.887900e-08
   3.687791e-06 + i   0.000000e+00        4.500353e-08
   2.792135e-06 + i   0.000000e+00        1.260036e-07
   2.676274e-06 + i   0.000000e+00        1.066106e-07
   2.485754e-06 + i   0.000000e+00        2.336125e-07
   2.265135e-06 + i   0.000000e+00        1.216118e-07
   2.123651e-06 + i   0.000000e+00        1.984118e-07
   2.083278e-06 + i   0.000000e+00        1.851201e-07
   1.964699e-06 + i   0.000000e+00        3.001937e-07
   1.894537e-06 + i   0.000000e+00        2.210573e-07
   1.808296e-06 + i   0.000000e+00        2.643175e-07
   1.767787e-06 + i   0.000000e+00        1.857689e-07
   1.712140e-06 + i   0.000000e+00        1.948303e-07
   1.673696e-06 + i   0.000000e+00        2.257906e-07
   1.666248e-06 + i   0.000000e+00        2.148936e-07
   1.623681e-06 + i   0.000000e+00        2.166838e-07
   1.609906e-06 + i   0.000000e+00        1.941363e-07
   1.468962e-06 + i   0.000000e+00        2.552411e-07
   1.426348e-06 + i   0.000000e+00        2.757035e-07
   1.405264e-06 + i   0.000000e+00        2.400259e-07
   1.376019e-06 + i   0.000000e+00        2.659608e-07
   1.301969e-06 + i   0.000000e+00        3.079990e-07
   1.284877e-06 + i   0.000000e+00        3.499356e-07
   1.246154e-06 + i   0.000000e+00        3.004309e-07
   1.233486e-06 + i   0.000000e+00        2.883003e-07
   1.125078e-06 + i   0.000000e+00        3.013997e-07
   1.083713e-06 + i   0.000000e+00        3.703915e-07
   1.021817e-06 + i   0.000000e+00        3.098594e-07

Error! Caught exception in BlockKrylovSchur::iterate() at iteration 7
terminate called after throwing an instance of 'std::logic_error'
  what():  solver/EVP/AnasaziBlockKrylovSchurTrackRes.hpp:1410:
Throw number = 1
Throw test that evaluated to true: ritzIndex_[numRitzVecs_-1]==1
Anasazi::BlockKrylovSchur::computeRitzVectors(): the number of required 
Ritz vectors splits a complex conjugate pair.

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