I want to update record after insert and after update , i am writing trigger 

trigger opMetricsTrigger on Operational_Metrics__c (after insert,after update)
{
     Operational_Metrics__c[] op=null;
     Set<string> opIds = new Set<string>();
     Date d1,d2;
       List<Operational_Metrics__c> c= new LIST<Operational_Metrics__c>();
     private static boolean run = true;
     if(run)
     {
       run=false;
     for (Operational_Metrics__c e : Trigger.new)
     {
         if(e.u_id__c != null)
         opIds.add(e.u_id__c );
     }
      
     List<Operational_Metrics__c> opm = [select Unique_Pile_ID__c,u_id__C, Project__c,Composting_Method__c,Pile_Monitoring_Date__c,Average_Temperature__c,Moisture_Test__c,Pile_Monitoring_Action_Taken__c,Other_Action__c,Pile_Input_Register_Date__c,Total_Waste_Input_on_the_Pile__c,Pile_Completion_Stage__c,Date_Pile_COmpleted__c,Curing_Batch_Register_Date__c,No_of_Days__c  from operational_metrics__c where u_id__c in :opIds];
     for(Operational_Metrics__c ops : opm)
     {
        if(ops.Pile_Completion_Stage__c=='yes')
         {
             System.debug('records1 are '+ops.Date_Pile_COmpleted__c);
             d1=ops.Date_Pile_COmpleted__c;
         } 
         else if(ops.Curing_Batch_Register_Date__c!=null)
         {
             d2=ops.Curing_Batch_Register_Date__c;
             System.debug('records2 are '+ops.Curing_Batch_Register_Date__c);
    
         }
        if(d1!=null && d2!=null)
        {
           
            ops.No_of_Days_for_piling__c=d1.daysBetween(d2);
             System.debug('no of days '+ops.No_of_Days_for_piling__c);
            c.add(ops);
        }
       
     }
    

       update c;
    }
}

I am able to get all debug logs correctly but when i am updating the record it is throwing CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY error which causes recursive calls to the trigger. could any one help me out.