Fixed crashing in LDA's learn_batch function in case l.sorted_features is empty. (When a socket connection is dropped, l.sorted_features may end up being empty. In that case, l.sorted_features[0] does not exist and therefore its address cannot be taken. This is probably not the best place nor the best way to fix it, though - but given my limited understanding of VW, I felt this was the best I could do, for now at least.)
Fixed crashing in LDA's learn_batch function in case l.sorted_features is empty. (When a socket connection is dropped, l.sorted_features may end up being empty. In that case, l.sorted_features[0] does not exist and therefore its address cannot be taken. This is probably not the best place nor the best way to fix it, though - but given my limited understanding of VW, I felt this was the best I could do, for now at least.)

jon-morra-zefr/vowpal_wabbit,zhoususheng/vowpal_wabbit,marko-asplund/vowpal_wabbit,lmatthieu/myvw,lmatthieu/myvw,deaktator/vowpal_wabbit-jmorra,michaelbrundage/vowpal_wabbit,followyourheart/vowpal_wabbit,martinbel/vowpal_wabbit,VerveWireless/vowpal_wabbit,raosudha89/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,VerveWireless/vowpal_wabbit,haipengl/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,robin-lai/vowpal_wabbit,deaktator/vowpal_wabbit-jmorra,robin-lai/vowpal_wabbit,chenmoshushi/vowpal_wabbit,emjotde/vowpal_wabbit,ffyu/vowpal_wabbit,gregsharp/vowpal_wabbit,deaktator/vowpal_wabbit,ml-lab/vowpal_wabbit,tzukuoh/vowpal_wabbit,zzzbit/vowpal_wabbit,pombredanne/vowpal_wabbit,byzhang/vowpal_wabbit,martinbel/vowpal_wabbit,lhoang29/vowpal_wabbit,martinbel/vowpal_wabbit,abimannans/vowpal_wabbit,pombredanne/vowpal_wabbit,marcovzla/vowpal_wabbit,multiworldtesting/explore-cpp,yonglehou/vowpal_wabbit,gregsharp/vowpal_wabbit,zermelozf/vw_tuto,emjotde/vowpal_wabbit,virneo/explore-cpp,marcovzla/vowpal_wabbit,chrinide/vowpal_wabbit,virneo/explore-cpp,martinpopel/vowpal_wabbit,danmelamed/vowpal_wabbit,ffyu/vowpal_wabbit,sandyice74/vowpal_wabbit,gregsharp/vowpal_wabbit,tsourolampis/vowpal_wabbit,emjotde/vowpal_wabbit,haipengl/vowpal_wabbit,trufanov-nok/vowpal_wabbit,marko-asplund/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,chrinide/vowpal_wabbit,virneo/explore,printedheart/vowpal_wabbit,hhexiy/vowpal_wabbit,chenmoshushi/vowpal_wabbit,hhexiy/vowpal_wabbit,printedheart/vowpal_wabbit,hhexiy/vowpal_wabbit,obrianjunior/vowpal_wabbit,haipengl/vowpal_wabbit,hal3/vowpal_wabbit,virneo/explore,stathwang/vowpal_wabbit,tsourolampis/vowpal_wabbit,digitalreasoning/vowpal_wabbit,zachmayer/vowpal_wabbit,pombredanne/vowpal_wabbit,robin-lai/vowpal_wabbit,marcovzla/vowpal_wabbit,ffyu/vowpal_wabbit,pombredanne/vowpal_wabbit,abimannans/vowpal_wabbit,swjo207/vowpal_wabbit,sandyice74/vowpal_wabbit,elevatedcareers/vowpal_wabbit,followyourheart/vowpal_wabbit,gregsharp/vowpal_wabbit,feynman0825/vowpal_wabbit,digitalreasoning/vowpal_wabbit,abimannans/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,printedheart/vowpal_wabbit,chenmoshushi/vowpal_wabbit,ffyu/vowpal_wabbit,haipengl/vowpal_wabbit,followyourheart/vowpal_wabbit,swjo207/vowpal_wabbit,emjotde/vowpal_wabbit,yonglehou/vowpal_wabbit,byzhang/vowpal_wabbit,abimannans/vowpal_wabbit,swjo207/vowpal_wabbit,digitalreasoning/vowpal_wabbit,digitalreasoning/vowpal_wabbit,emjotde/vowpal_wabbit,ffyu/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,printedheart/vowpal_wabbit,michaelbrundage/vowpal_wabbit,raosudha89/vowpal_wabbit,stathwang/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,martinbel/vowpal_wabbit,chrinide/vowpal_wabbit,multiworldtesting/explore,michaelbrundage/vowpal_wabbit,followyourheart/vowpal_wabbit,obrianjunior/vowpal_wabbit,hal3/vowpal_wabbit,haipengl/vowpal_wabbit,haipengl/vowpal_wabbit,ml-lab/vowpal_wabbit,obrianjunior/vowpal_wabbit,lhoang29/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,yonglehou/vowpal_wabbit,feynman0825/vowpal_wabbit,danmelamed/vowpal_wabbit,michaelbrundage/vowpal_wabbit,gregsharp/vowpal_wabbit,abimannans/vowpal_wabbit,feynman0825/vowpal_wabbit,raosudha89/vowpal_wabbit,multiworldtesting/explore-cpp,chenmoshushi/vowpal_wabbit,chenmoshushi/vowpal_wabbit,zzzbit/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,obrianjunior/vowpal_wabbit,obrianjunior/vowpal_wabbit,zhoususheng/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,danmelamed/vowpal_wabbit,jmorra/vowpal_wabbit,lhoang29/vowpal_wabbit,hhexiy/vowpal_wabbit,deaktator/vowpal_wabbit-jmorra,multiworldtesting/explore,swjo207/vowpal_wabbit,zachmayer/vowpal_wabbit,martinbel/vowpal_wabbit,danmelamed/vowpal_wabbit,digitalreasoning/vowpal_wabbit,digitalreasoning/vowpal_wabbit,followyourheart/vowpal_wabbit,lmatthieu/myvw,emjotde/vowpal_wabbit,trufanov-nok/vowpal_wabbit,deaktator/vowpal_wabbit,raosudha89/vowpal_wabbit,lmatthieu/myvw,elkingtonmcb/vowpal_wabbit,zermelozf/vw_tuto,VerveWireless/vowpal_wabbit,zhoususheng/vowpal_wabbit,trufanov-nok/vowpal_wabbit,followyourheart/vowpal_wabbit,jmorra/vowpal_wabbit,multiworldtesting/decision,martinpopel/vowpal_wabbit,marcovzla/vowpal_wabbit,sandyice74/vowpal_wabbit,marcovzla/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,michaelbrundage/vowpal_wabbit,jmorra/vowpal_wabbit,trufanov-nok/vowpal_wabbit,printedheart/vowpal_wabbit,digitalreasoning/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,byzhang/vowpal_wabbit,byzhang/vowpal_wabbit,robin-lai/vowpal_wabbit,danmelamed/vowpal_wabbit,deaktator/vowpal_wabbit,marko-asplund/vowpal_wabbit,zachmayer/vowpal_wabbit,martinpopel/vowpal_wabbit,hhexiy/vowpal_wabbit,emjotde/vowpal_wabbit,ml-lab/vowpal_wabbit,jmorra/vowpal_wabbit,stathwang/vowpal_wabbit,chrinide/vowpal_wabbit,feynman0825/vowpal_wabbit,ml-lab/vowpal_wabbit,elevatedcareers/vowpal_wabbit,ffyu/vowpal_wabbit,raosudha89/vowpal_wabbit,deaktator/vowpal_wabbit,haipengl/vowpal_wabbit,followyourheart/vowpal_wabbit,robin-lai/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,tsourolampis/vowpal_wabbit,hhexiy/vowpal_wabbit,zachmayer/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,danmelamed/vowpal_wabbit,emjotde/vowpal_wabbit,lhoang29/vowpal_wabbit,jmorra/vowpal_wabbit,yonglehou/vowpal_wabbit,followyourheart/vowpal_wabbit,byzhang/vowpal_wabbit,pombredanne/vowpal_wabbit,hal3/vowpal_wabbit,zachmayer/vowpal_wabbit,haipengl/vowpal_wabbit,martinpopel/vowpal_wabbit,haipengl/vowpal_wabbit,hal3/vowpal_wabbit,sandyice74/vowpal_wabbit,hhexiy/vowpal_wabbit,marko-asplund/vowpal_wabbit,ml-lab/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,printedheart/vowpal_wabbit,chenmoshushi/vowpal_wabbit,lhoang29/vowpal_wabbit,feynman0825/vowpal_wabbit,elevatedcareers/vowpal_wabbit,hal3/vowpal_wabbit,hal3/vowpal_wabbit,martinpopel/vowpal_wabbit,swjo207/vowpal_wabbit,byzhang/vowpal_wabbit,abimannans/vowpal_wabbit,zhoususheng/vowpal_wabbit,abimannans/vowpal_wabbit,zachmayer/vowpal_wabbit,zzzbit/vowpal_wabbit,hal3/vowpal_wabbit,deaktator/vowpal_wabbit-jmorra,deaktator/vowpal_wabbit-jmorra,elevatedcareers/vowpal_wabbit,ml-lab/vowpal_wabbit,stathwang/vowpal_wabbit,hhexiy/vowpal_wabbit,printedheart/vowpal_wabbit,stathwang/vowpal_wabbit,ml-lab/vowpal_wabbit,zermelozf/vw_tuto,pombredanne/vowpal_wabbit,multiworldtesting/explore,chrinide/vowpal_wabbit,zzzbit/vowpal_wabbit,lmatthieu/myvw,jmorra/vowpal_wabbit,trufanov-nok/vowpal_wabbit,tzukuoh/vowpal_wabbit,trufanov-nok/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,VerveWireless/vowpal_wabbit,robin-lai/vowpal_wabbit,lhoang29/vowpal_wabbit,tsourolampis/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,zhoususheng/vowpal_wabbit,deaktator/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,sandyice74/vowpal_wabbit,jmorra/vowpal_wabbit,sandyice74/vowpal_wabbit,pombredanne/vowpal_wabbit,martinbel/vowpal_wabbit,robin-lai/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,ffyu/vowpal_wabbit,sandyice74/vowpal_wabbit,elevatedcareers/vowpal_wabbit,obrianjunior/vowpal_wabbit,swjo207/vowpal_wabbit,VerveWireless/vowpal_wabbit,emjotde/vowpal_wabbit,michaelbrundage/vowpal_wabbit,tsourolampis/vowpal_wabbit,chenmoshushi/vowpal_wabbit,printedheart/vowpal_wabbit,pombredanne/vowpal_wabbit,byzhang/vowpal_wabbit,lhoang29/vowpal_wabbit,tzukuoh/vowpal_wabbit,marko-asplund/vowpal_wabbit,feynman0825/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,tzukuoh/vowpal_wabbit,zachmayer/vowpal_wabbit,chrinide/vowpal_wabbit,pombredanne/vowpal_wabbit,marko-asplund/vowpal_wabbit,danmelamed/vowpal_wabbit,hal3/vowpal_wabbit,marcovzla/vowpal_wabbit,feynman0825/vowpal_wabbit,elevatedcareers/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,yonglehou/vowpal_wabbit,digitalreasoning/vowpal_wabbit,yonglehou/vowpal_wabbit,VerveWireless/vowpal_wabbit,multiworldtesting/explore-csharp,deaktator/vowpal_wabbit-jmorra,tzukuoh/vowpal_wabbit,elevatedcareers/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,jmorra/vowpal_wabbit,VerveWireless/vowpal_wabbit,followyourheart/vowpal_wabbit,eisber/mwt-ds,stathwang/vowpal_wabbit,tsourolampis/vowpal_wabbit,deaktator/vowpal_wabbit-jmorra,tzukuoh/vowpal_wabbit,feynman0825/vowpal_wabbit,swjo207/vowpal_wabbit,gregsharp/vowpal_wabbit,digitalreasoning/vowpal_wabbit,deaktator/vowpal_wabbit,martinpopel/vowpal_wabbit,eisber/mwt-ds,feynman0825/vowpal_wabbit,chriszeng8/vowpal_wabbit,hhexiy/vowpal_wabbit,eisber/mwt-ds,obrianjunior/vowpal_wabbit,sandyice74/vowpal_wabbit,VerveWireless/vowpal_wabbit,abimannans/vowpal_wabbit,marcovzla/vowpal_wabbit,byzhang/vowpal_wabbit,martinpopel/vowpal_wabbit,digitalreasoning/vowpal_wabbit,michaelbrundage/vowpal_wabbit,emjotde/vowpal_wabbit,jmorra/vowpal_wabbit,zachmayer/vowpal_wabbit,zhoususheng/vowpal_wabbit,zzzbit/vowpal_wabbit,raosudha89/vowpal_wabbit,chenmoshushi/vowpal_wabbit,chenmoshushi/vowpal_wabbit,robin-lai/vowpal_wabbit,ml-lab/vowpal_wabbit,hal3/vowpal_wabbit,tzukuoh/vowpal_wabbit,zzzbit/vowpal_wabbit,danmelamed/vowpal_wabbit,martinbel/vowpal_wabbit,jmorra/vowpal_wabbit,michaelbrundage/vowpal_wabbit,byzhang/vowpal_wabbit,ml-lab/vowpal_wabbit,tzukuoh/vowpal_wabbit,ml-lab/vowpal_wabbit,deaktator/vowpal_wabbit,lmatthieu/myvw,printedheart/vowpal_wabbit,gregsharp/vowpal_wabbit,tsourolampis/vowpal_wabbit,zermelozf/vw_tuto,yonglehou/vowpal_wabbit,abimannans/vowpal_wabbit,zermelozf/vw_tuto,marcovzla/vowpal_wabbit,obrianjunior/vowpal_wabbit,zzzbit/vowpal_wabbit,marko-asplund/vowpal_wabbit,gregsharp/vowpal_wabbit,stathwang/vowpal_wabbit,zhoususheng/vowpal_wabbit,zzzbit/vowpal_wabbit,marcovzla/vowpal_wabbit,stathwang/vowpal_wabbit,marko-asplund/vowpal_wabbit,sandyice74/vowpal_wabbit,trufanov-nok/vowpal_wabbit,feynman0825/vowpal_wabbit,martinbel/vowpal_wabbit,haipengl/vowpal_wabbit,elevatedcareers/vowpal_wabbit,chrinide/vowpal_wabbit,VerveWireless/vowpal_wabbit,deaktator/vowpal_wabbit-jmorra,deaktator/vowpal_wabbit,swjo207/vowpal_wabbit,zermelozf/vw_tuto,raosudha89/vowpal_wabbit,gregsharp/vowpal_wabbit,zermelozf/vw_tuto,VerveWireless/vowpal_wabbit,zzzbit/vowpal_wabbit,robin-lai/vowpal_wabbit,elevatedcareers/vowpal_wabbit,hhexiy/vowpal_wabbit,deaktator/vowpal_wabbit-jmorra,robin-lai/vowpal_wabbit,zermelozf/vw_tuto,printedheart/vowpal_wabbit,zhoususheng/vowpal_wabbit,chriszeng8/vowpal_wabbit,raosudha89/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,chriszeng8/vowpal_wabbit,tzukuoh/vowpal_wabbit,chrinide/vowpal_wabbit,zhoususheng/vowpal_wabbit,chenmoshushi/vowpal_wabbit,martinpopel/vowpal_wabbit,lhoang29/vowpal_wabbit,martinbel/vowpal_wabbit,martinpopel/vowpal_wabbit,ffyu/vowpal_wabbit,trufanov-nok/vowpal_wabbit,chriszeng8/vowpal_wabbit,martinbel/vowpal_wabbit,obrianjunior/vowpal_wabbit,trufanov-nok/vowpal_wabbit,michaelbrundage/vowpal_wabbit,trufanov-nok/vowpal_wabbit,ffyu/vowpal_wabbit,marko-asplund/vowpal_wabbit,byzhang/vowpal_wabbit,swjo207/vowpal_wabbit,deaktator/vowpal_wabbit,deaktator/vowpal_wabbit,chriszeng8/vowpal_wabbit,yonglehou/vowpal_wabbit,ffyu/vowpal_wabbit,raosudha89/vowpal_wabbit,stathwang/vowpal_wabbit,tzukuoh/vowpal_wabbit,zachmayer/vowpal_wabbit,zzzbit/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,zachmayer/vowpal_wabbit,chrinide/vowpal_wabbit,chriszeng8/vowpal_wabbit,tsourolampis/vowpal_wabbit,KaiWeiChang/vowpal_wabbit,chriszeng8/vowpal_wabbit,zermelozf/vw_tuto,abimannans/vowpal_wabbit,swjo207/vowpal_wabbit,deaktator/vowpal_wabbit-jmorra,raosudha89/vowpal_wabbit,elevatedcareers/vowpal_wabbit,virneo/explore,obrianjunior/vowpal_wabbit,chriszeng8/vowpal_wabbit,pombredanne/vowpal_wabbit,danmelamed/vowpal_wabbit,michaelbrundage/vowpal_wabbit,zermelozf/vw_tuto,chriszeng8/vowpal_wabbit,gregsharp/vowpal_wabbit,yonglehou/vowpal_wabbit,yonglehou/vowpal_wabbit,stathwang/vowpal_wabbit,tsourolampis/vowpal_wabbit,sandyice74/vowpal_wabbit,zhoususheng/vowpal_wabbit,elkingtonmcb/vowpal_wabbit,lhoang29/vowpal_wabbit,lmatthieu/myvw,followyourheart/vowpal_wabbit,lmatthieu/myvw,elkingtonmcb/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,deaktator/vowpal_wabbit,martinpopel/vowpal_wabbit,lhoang29/vowpal_wabbit,chriszeng8/vowpal_wabbit,sidsen/mwt-ds-decision,danmelamed/vowpal_wabbit,marko-asplund/vowpal_wabbit,hal3/vowpal_wabbit,hal3/vowpal_wabbit,marcovzla/vowpal_wabbit,jon-morra-zefr/vowpal_wabbit,lmatthieu/myvw