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user.c -- user-definable operations

This section contains functions and constants that the user may want to change.

Copyright © 1995-2020 C.B. Barber

» Geom • Global • Io • Mem • Merge • Poly • Qhull • Set • Stat • User

Index to user.c, usermem.c, userprintf.c, userprintf_rbox.c and user.h

• qhull library constants
• user.h data types and configuration macros
• joggle constants
• performance related constants
• memory constants
• conditional compilation
• merge constants
• user.c functions
• usermem.c functions
• userprintf.c functions

»Qhull library constants

• FILENAMElen -- max length of TI or TO filename
• msgcode -- unique message codes for qh_fprintf
• qh_OPTIONline -- max length of option line ('FO')

»user.h data types and configuration macros

• realT, qh_REAL... size of floating point numbers
• countT, COUNTmax size of counts and identifiers, typically 'int' or 'long long'
• qh_CPUclock clock() function for reporting the total time spent by Qhull
• qh_RANDOM... random number generator

»definition constants

• qh_DEFAULTbox define default box size for rbox, 'Qbb', and 'QbB' (Geomview expects 0.5)
• qh_INFINITE on output, indicates Voronoi center at infinity
• qh_ORIENTclock define convention for orienting facets
• qh_RANDOMdist for testing qh.DISTround (sets qh.RANDOMfactor for qh.RANDOMdist, same as option 'Rn')

»joggle constants

• qh_JOGGLEagain how often to retry before using qh_JOGGLEmaxincrease again
• qh_JOGGLEdefault default value for qh.JOGGLEmax for 'QP'
• qh_JOGGLEincrease factor to increase qh.JOGGLEmax on retrys for 'QPn'
• qh_JOGGLEmaxincrease max for increasing qh.JOGGLEmax relative to qh.MAXwidth
• qh_JOGGLEmaxretry report error if this many retries
• qh_JOGGLEretry how often to retry before using qh_JOGGLEmax

»performance related constants

• qh_HASHfactor total/used hash slots
• qh_INITIALmax if dim >= qh_INITIALmax, use min/max coordinate points for initial simplex
• qh_INITIALsearch if qh.INITIALmax, search points up to this dimension
• qh_NOtrace disallow tracing
• qh_VERIFYdirect 'Tv' verifies all points X facets if op count is smaller

»memory constants

• qh_MEMalign memory alignment for qh_meminitbuffers() in global.c
• qh_MEMbufsize size of additional memory buffers
• qh_MEMinitbuf size of initial memory buffer

»conditional compilation

• compiler defined symbols, e.g., _STDC_ and _cplusplus
• qh_COMPUTEfurthest compute furthest distance to an outside point instead of storing it with the facet
• qh_KEEPstatistics enable statistic gathering and reporting with option 'Ts'
• qh_MAXcheckpoint report up to qh_MAXcheckpoint errors per facet in qh_check_point ('Tv')
• qh_MAXoutside record outer plane for each facet
• qh_NOmerge disable facet merging
• qh_NOtrace disable tracing with option 'T4'
• qh_QHpointer access global data with pointer or static structure
• qh_QUICKhelp use abbreviated help messages, e.g., for degenerate inputs

»merge constants

• qh_BESTcentrum if many vertices for facet, qh_findbestneighbor tests centrums instead of vertices
• qh_BESTnonconvex if many neighbors for facet, qh_findbestneighbor only tests nonconvex ridges
• qh_COPLANARratio what is qh.MINvisible?
• qh_DIMreduceBuild max dimension for vertex reduction
• qh_DIMmergeVertex max dimension for vertex merging
• qh_DISToutside when is a point clearly outside of a facet for qh_findbestnew and qh_partitionall
• qh_MAXnarrow max. cosine for qh.NARROWhull
• qh_MAXcoplanarcentrum if 'Qx' and many merges, use f.maxoutside for coplanarity test instead of qh.centrum_radius
• qh_MAXnarrow max. cosine in initial hull that sets qh.NARROWhull
• qh_MAXnewcentrum when does qh_reducevertices_centrum() reset the centrum?
• qh_MAXnewmerges when does qh_merge_nonconvex() call qh_reducevertices_centrums?
• qh_RATIOconcavehorizon ratio of horizon vertex distance to qh.max_outside for concave, twisted new facets in qh_test_nonsimplicial_merge
• qh_RATIOconvexmerge ratio of vertex distance to qh.min_vertex for clearly convex new facets in qh_test_nonsimplicial_merge
• qh_RATIOcoplanarapex ratio of best distance for coplanar apex vs. vertex merge in qh_getpinchedmerges
• qh_RATIOcoplanaroutside ratio to repartition a coplanar point as an outside point in qh_partitioncoplanar and qh_check_maxout
• qh_RATIOmaxsimplex ratio for searching all points in qh_maxsimplex
• qh_RATIOnearinside ratio for retaining inside points for qh_check_maxout
• qh_RATIOpinchedsubridge ratio to qh.ONEmerge to accept vertices in qh_findbest_pinchedvertex
• qh_RATIOtrypinched ratio to qh.ONEmerge to try qh_getpinchedmerges in qh_buildcone_mergepinched
• qh_RATIOtwisted maximum ratio to qh.ONEmerge to merge twisted facets in qh_merge_twisted
• qh_SEARCHdist when is facet coplanar with the best facet for qh_findbesthorizon
• qh_USEfindbestnew when to use qh_findbestnew for qh_partitionpoint()
• qh_WARNnarrow max. cosine in initial hull to warn about qh.NARROWhull
• qh_WIDEcoplanar what is a wide facet
• qh_WIDEduplicate merge ratio for errexit from qh_forcedmerges due to duplicate ridge
• qh_WIDEridge merge ratio for selecting a forced dupridge merge
• qh_WIDEmaxoutside precision ratio for maximum increase for qh.max_outside in qh_check_maxout
• qh_WIDEmaxoutside2 precision ratio for maximum qh.max_outside in qh_check_maxout
• qh_WIDEpinched merge ratio for distance between pinched vertices compared to current facet width for qh_getpinchedmerges and qh_next_vertexmerge
• qh_ZEROdelaunay define facets that are ignored in Delaunay triangulations

»user.c functions

• Qhull template for calling qh_new_qhull from your program
• qh_errexit report error and exit qhull()
• qh_errprint print information about facets and ridges
• qh_new_qhull call qhull on an array of points
• qh_printfacetlist print all fields of all facets
• qh_printhelp_degenerate prints descriptive message for precision error
• qh_printhelp_internal print help message for an internal error
• qh_printhelp_narrowhull prints descriptive message to warn about a narrow hull
• qh_printhelp_singular print help message for singular data
• qh_printhelp_topology print help message for a topology error due to merging
• qh_printhelp_wide print help message for a wide merge error
• qh_user_memsizes define additional quick allocation sizes

»usermem.c functions

• qh_exit exit program, same as exit(). May be redefined as throw "QH10003.." by libqhullcpp/usermem_r-cpp.cpp
• qh_fprintf_stderr print to stderr when qh.ferr is not defined.
• qh_free free memory, same as free().
• qh_malloc allocate memory, same as malloc()

»userprintf.c and userprintf_rbox,c functions

• qh_fprintf print information from Qhull, sames as fprintf().
• qh_fprintf_rbox print information from Rbox, sames as fprintf().

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Comments to: qhull@qhull.org
Created: May 2, 1997 --- Last modified: see top