[Pw_forum] Conjugate Gradient minimization not converged after 50 iterations

[Jonas Baltrusaitis]

Dear all,

while running normal mode calculation on a large system I can see that conjugate gradient minimization does not converge after 50 iterations in some modes. By inspection, some modes converge in 46-48 iterations. Would increasing number of iterations solve that problem? Is it a problem at all as residual after 50 iterations is quite small, does that mean it's acceptable as calculations continue?


 ***  Starting Conjugate Gradient minimization         ***
     d2ion: alpha =   0.50
 ***  mode #   1 : using asr
 ***  mode #   2 : using asr
 ***  mode #   3 : using asr
 ***  mode #   4 :  46 iterations
 ***  mode #   5 :  45 iterations
 ***  mode #   6 :  48 iterations
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.1718E-13
 ***  mode #   7 :  50 iterations
   *** Conjugate Gradient minimization not converged after  50 iterations
 residual norm |Ax-b|^2 : 0.1148E-13
 ***  mode #   8 :  50 iterations

thanks

Jonas Baltrusaitis
University of Iowa