*-- Author : R. Henderson
SUBROUTINE FPDG33(IP)
**: FPDG33 40000 RH. New steering parameter.
*------------------------------------------------------------------
**: FPDG33 30907 RH. Bug fix in cluster finding.
C------------------------------------------------------------------
C
C--- This routine finds clusters from 3 digitizings
C--- wires 2 3 4 only
C--- This routine should always be called from within FPDG4
C--- after FPDG31
C
C---
*KEEP,FPPRAM.
C
C--- MAXSEG is maximum number of segments per supermodule
C--- MAXCON is maximum number of amibiguous segments associatable with
C--- one segment
C--- LIMSTO is maximum number of 2 cluster planes intersections to be
C--- stored per supermodule
C--- MSEGLM is maximum number of clusters that can be found before
C--- connectivity considered
C--- MAXCLU is maximum number of clusters that can be found after
C--- forming non-connected set MUST BE 50 IF RUN WITH OLD RCW
C--- (cluster = 3/4 digits found in a straight line in one
C--- 4-wire orientation)
C
C---
*KEND.
C---
*KEEP,FPLGEO.
C---
C---
*KEND.
C---
*KEEP,FPCLUS.
C---
*KEND.
C---
*KEEP,FPH1WRK.
C-- *KEEP,FPCSEG.
C---
C---
C-- *KEEP,FPDIGI.
C---
C-- *KEEP,FPDGI.
C---
C-- *KEEP,FPSTID.
C---
C-- *interface to real data
C---.
*KEND.
C---
C---
C-------------------------------------------------------------------
C DIGITS ANALYSIS
C
C The following arrays are used in the remainder of this routine
C
C drsto(drift,wire_in_orientation):
C This has both drift and reflection per orientation
C
C ndrsto(wire_in_orientation):
C Number of drifts + reflections on wire (Naughty)
C
C drmask(drift,wire_in_orientation):
C 1.0 If digit or reflection used
C 0.0 If digit or reflection unused
C
C idigst(wire_in_orientation,found_segment_candidate):
C index of digitising associated with a particular
C candidate segment for a particular wire
C
C nsgtab(candidate_segment):
C Number of candidate segments with which current segment
C shares digitizings
C
C segtab(candidate_segment,associated_ambiguous_segments):
C segment index ambiguous with current segment
C
C-------------------------------------------------------------------
C
C--- tolerance for finding digitizings
C
C
C--- define maximum slope to be found for segment
C
C
C--- Section to find 2d line segments
C
C--- loop over first and last wire in orientation
C--- but allow one of the intermediate points to be missing
C
C
C--- entry point for more relaxed segment search
C--- ifirst = 1 on first pass through
C
C
C--- determine if dealing with a split cell
C
C
C--- On first pass filter out large slopes
C
C---
C
C--- use tolerance to find digitizings to form segments
C
C
C--- plane 2
C
C
C--- store the digitizing per segment found
C
CALL ERRLOG(209,'W:FPDG33: NSEG > MSEGLM')
C
C--- Now sort out which initial segments to keep
C
C
C--- Create segtab showing interconnectivity
C
CALL VZERO(NSGTAB,MSEGLM)
C
C--- loop over remaining segments
C
C
C--- comparison loop over each wire in turn
C
C
C--- has the same wire the same digit
C
C
C--- remove nodes greater than or equal to 3
C
CALL VFLOAT(NSGTAB,ASGTAB,NSEG)
C
C--- greater than 2.0 so remove by setting nsgtab = -1.0
C
C
C--- Now remove any reference to this node in the remaining nodes
C
C
C--- Now try to find loops and angles and eliminate
C
C
C--- Find first candidate with 2 links
C
C
C--- Now trace its path
C
C
C--- Entry point for step along chain
C
C
C--- Test if path at end
C
C
C--- Skip link if pointing back
C
C
C--- Store next element of chain
C
C
C--- Test if loop complete
C
C
C--- Points to next element in chain
C
C
C--- End of branch one
C
C
C--- This cannot be a loop so kill off node
C
C
C--- Now remove any reference to this node in the remaining nodes
C
C
C--- Now continue on node loop
C
C
C--- Loop complete
C
C
C--- Perform fits and eliminate all but one node in loop
C
CALL FPCFIT(IP,Y,W,SLOPE,ZERO,COVSLZ,CHISQ,PBCHI)
C
C--- Keep only highest probability iff prob gt 10**-5
C
C
C--- now loop over segments and remove all but the saved
C
C
C--- Now remove any reference to this node in the remaining nodes
C
C
C
C--- now remove any pairs by fitting
C
C
C--- Found a pair so find partner
C
C
C--- fit the first possiblity
C
CALL FPCFIT(IP,Y,W,SLOPE,ZERO,COVSLZ,CHISQ1,PBCHI1)
C
C--- Fit the second possiblity
C
CALL FPCFIT(IP,Y,W,SLOPE,ZERO,COVSLZ,CHISQ2,PBCHI2)
C
C--- Now remove the smaller probability segment
C
C
C--- Now remove any reference to this node in the remaining nodes
C
C
C--- Now draw remaining segments
C
C
C--- fit remaining segments
C
CALL FPCFIT(IP,Y,W,SLOPE,ZERO,COVSLZ,CHISQ,PBCHI)
C%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
C
C--- find the absolute coordinate normal current wire orientation
C
C
C--- find which orientation plane (1-9) is current
C
C
C--- find fitted 'y' position at begining and end of 4 wire set
C--- fdrsta and fdrend respectively
C
C
C--- Transform from orientation drift coordinates to global coordinates
C--- assuming that drift x coordinate is zero
C
C
C--- Fill track cluster banks and banks counter
C
C
C--- Increment cluster counter per plane
C
CALL ERRLOG(210,'W:FPDG33: NTC(IPLANE) > MAXCLU')
C
C--- store toc
C
C
C--- store the digitisings associated with plane/track for final
C fit
C
C%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
C
C--- Now plot unused digitisizings
C
C
C--- Set drmask to 1.0 for used digits
C
C
C--- If first pass now loop back with 2*tolerance and 3*maxang
C
*