*-- Author : S.Burke / J.V. Morris
      SUBROUTINE FKRST(JPL,IERR)
**********************************************************************                                        
*                                                                    *                                        
* Calculate residuals and chi-squared between the smoothed and true  *                                        
* vectors at plane JPL                                               *                                        
*                                                                    *                                        
* ERROR CONDITIONS;                                                  *                                        
*       IERR =   0  ; normal termination                             *                                        
*   ->  IERR = 111  ; smoothed covariance not positive definite      *                                        
*                                                                    *                                        
*   ->  Fatal error                                                  *                                        
*                                                                    *                                        
**********************************************************************                                        
*KEEP,FKECODE.                                                                                                
*KEND.                                                                                                        
*KEEP,FKNPL.                                                                                                  
*                                                                                                             
* Per-track values can go in H1WORK; note that LTRUE and LFIRST must                                          
* be set at least per event.                                                                                  
*                                                                                                             
* This is about 36k words long; the remaining common blocks are                                               
* about 3.6k in total. Some of this could be in /H1WORK/, but the                                             
* blocks would have to be reorganised.                                                                        
*                                                                                                             
* /FKPROJ/                                                                                                    
* /FKFILT/                                                                                                    
* /FKSMTH/                                                                                                    
* /FKINT/                                                                                                     
* /FKRSID/                                                                                                    
* /FKTRUE/                                                                                                    
* /FKDBG/                                                                                                     
*KEEP,FKTRUE.                                                                                                 
*KEEP,FKSMTH.                                                                                                 
*KEND.                                                                                                        
**********************************************************************                                        
*                                                                                                             
* Calculate the residuals ...                                                                                 
*                                                                                                             
      CALL FKDIFF(TRUE(1,JPL),SSMT(1,JPL),RTRUE(1,JPL))
*                                                                                                             
* ... and the chi-squared                                                                                     
*                                                                                                             
      CALL UCOPY(CSMT(1,1,JPL),CT,50)                                                                  
      CALL DSINV(5,CT,5,IFAIL)                                                                         
         CALL FKERR(IUTIL,IROUT,IFATAL,IOCV,IERR)
*