fix len_x spark
fix len_x spark

MarkAWard/optunity,chrinide/optunity,MarkAWard/optunity,claesenm/optunity,chrinide/optunity,claesenm/optunity,claesenm/optunity,MarkAWard/optunity,chrinide/optunity,MarkAWard/optunity,chrinide/optunity,claesenm/optunity