[petsc-users] Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE

[李瑞]

Dear professor or engineer:
   I recently attempt to solve the system of equation that consist of two sub equations,which are respetivly spatially and timely dependant.The structure of equations are likely : F_1(x,y)=0;F_2(w(t),x)=0.and y can be explicitly obtained in each time step.We need to pay attention to the first equation is a linear equation and the second a  nonlinear equation dependent on time.Getting W(t0) by sequentially obtain y and x.
   When I solve the equation F1 in first time step,the result was convergent,but in the second step was not.The answer reveals that:
>>>In the first time step:
      ....
  126 KSP Residual norm 6.505554772167e-03 
  127 KSP Residual norm 2.563866095029e-03 
  128 KSP Residual norm 5.365504095451e-04 
  129 KSP Residual norm 9.699344087450e-05 
  130 KSP Residual norm 2.793539286585e-05 
  131 KSP Residual norm 8.413249813721e-06 
  132 KSP Residual norm 2.488394296066e-06 
  133 KSP Residual norm 1.055822777756e-06 
  134 KSP Residual norm 7.820629842889e-07
Nonlinear solve converged due to CONVERGED_ITS

>>>In the second time step :
       ....
  294 KSP Residual norm 2.632117164436e+03 
  295 KSP Residual norm 2.627315190869e+03 
  296 KSP Residual norm 2.626944159914e+03 
  297 KSP Residual norm 2.625073489387e+03 
  298 KSP Residual norm 2.624035038684e+03 
  299 KSP Residual norm 2.623956156495e+03 
  300 KSP Residual norm 2.623696336837e+03
Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE

The following code is typing my makefile.
-linear_ksp_monitor -linear_snes_converged_reason -linear_snes_atol 1.e-4 -linear_snes_rtol 1.e-60 -linear_ksp_type gmres \
-linear_ksp_max_it 300 -linear_ksp_atol 1.e-6 -linear_ksp_gmres_restart 90 -linear_ksp_rtol 1.e-60 \
-linear_ksp_pc_side right -linear_pc_type asm -linear_pc_asm_type restrict -linear_pc_asm_overlap 1 \
-linear_sub_ksp_type preonly -linear_sub_pc_type lu \

 Is there anything wrong,Pc_type or Krylov method?Can you give me some detailed suggestions or other ways to solve my obsession？Thank for your heartful help!