I have encountered a convergence problem in my structure device in Transiesta calculation, the calculation doesn't converge. Recently I try to decrease the mixing weight parameter to 0.00001. For some small structures, it stops at 300 iterations without convergence. For big sizes strucutre (even with 0V), it tacks more than a month without convergence. I would be grateful if can any one solve my problem with this error any suggestion will be appreciated.