R&B singer Frank Ocean revealed over the weekend he was canceling a string of planned tour dates including a headlining spot at Sweden's Way Out festival and a run of stadium appearances with Coldplay.  In a statement from Ocean and relayed by Way Out's organizers, Ocean noted: "Let me start by saying I feel like an asshole right now, but a tough decision had to be made in regard to my schedule over the next months."  Ocean did not offer any further explanation for the cancellations, but the announcement came after he was forced to cut short a performance in Norway last Friday due to "vocal problems."