from __future__ import generators
import config.base
import config.package
import os
from stat import *

def noCheck(command, status, output, error):
  ''' Do no check result'''
  return

class Configure(config.package.Package):
  def __init__(self, framework):
    config.package.Package.__init__(self, framework)
    self.minversion         = '2'
    self.versionname        = 'MPI_VERSION'
    self.functions          = ['MPI_Init', 'MPI_Comm_create']
    self.includes           = ['mpi.h']
    liblist_mpich         = [['fmpich2.lib','fmpich2g.lib','fmpich2s.lib','mpi.lib'],
                             ['fmpich2.lib','fmpich2g.lib','mpi.lib'],['fmpich2.lib','mpich2.lib'],
                             ['libfmpich2g.a','libmpi.a'],['libfmpich.a','libmpich.a', 'libpmpich.a'],
                             ['libmpich.a', 'libpmpich.a'],
                             ['libfmpich.a','libmpich.a', 'libpmpich.a', 'libmpich.a', 'libpmpich.a', 'libpmpich.a'],
                             ['libmpich.a', 'libpmpich.a', 'libmpich.a', 'libpmpich.a', 'libpmpich.a'],
                             ['libmpich.a','librt.a','libaio.a','libsnl.a','libpthread.a'],
                             ['libmpich.a','libssl.a','libuuid.a','libpthread.a','librt.a','libdl.a'],
                             ['libmpich.a','libnsl.a','libsocket.a','librt.a','libnsl.a','libsocket.a'],
                             ['libmpich.a','libgm.a','libpthread.a']]
    liblist_lam           = [['liblamf77mpi.a','libmpi++.a','libmpi.a','liblam.a'],
                             ['liblammpi++.a','libmpi.a','liblam.a'],
                             ['liblammpio.a','libpmpi.a','liblamf77mpi.a','libmpi.a','liblam.a'],
                             ['liblammpio.a','libpmpi.a','liblamf90mpi.a','libmpi.a','liblam.a'],
                             ['liblammpio.a','libpmpi.a','libmpi.a','liblam.a'],
                             ['liblammpi++.a','libmpi.a','liblam.a'],
                             ['libmpi.a','liblam.a']]
    liblist_msmpi         = [[os.path.join('amd64','msmpifec.lib'),os.path.join('amd64','msmpi.lib')],
                             [os.path.join('i386','msmpifec.lib'),os.path.join('i386','msmpi.lib')],
                             [os.path.join('x64','msmpifec.lib'),os.path.join('x64','msmpi.lib')],
                             [os.path.join('x86','msmpifec.lib'),os.path.join('x86','msmpi.lib')],
                             ['msmpi.lib']]
    liblist_other         = [['libmpich.a','libpthread.a'],['libmpi++.a','libmpi.a']]
    liblist_single        = [['libmpi.a'],['libmpich.a'],['mpi.lib'],['mpich2.lib'],['mpich.lib'],
                             [os.path.join('amd64','msmpi.lib')],[os.path.join('i386','msmpi.lib')],
                             [os.path.join('x64','msmpi.lib')],[os.path.join('x86','msmpi.lib')]]
    self.liblist          = liblist_mpich + liblist_lam + liblist_msmpi + liblist_other + liblist_single
    # defaults to --with-mpi=yes
    self.required         = 1
    self.isPOE            = 0
    self.usingMPIUni      = 0
    self.shared           = 0
    # local state
    self.needBatchMPI     = 1
    self.alternativedownload = 'mpich'
    self.haveReduceLocal  = 0
    # support MPI-3 process shared memory
    self.support_mpi3_shm = 0
    self.mpi_pkg_version  = ''
    self.mpi_pkg          = '' # mpich,mpich2,mpich3,openmpi,intel,intel2,intel3

    # mpiexec, absolute path, and sequential run
    self.mpiexec           = None
    self.mpiexecExecutable = None
    self.mpiexecseq        = None
    return

  def setupHelp(self, help):
    config.package.Package.setupHelp(self,help)
    import nargs
    help.addArgument('MPI', '-with-mpiexec=<prog>',                              nargs.Arg(None, None, 'The utility used to launch MPI jobs. (should support "-n <np>" option)'))
    help.addArgument('MPI', '-with-mpiexec-tail=<prog>',                         nargs.Arg(None, None, 'The utility you want to put at the very end of "mpiexec -n <np> ..." and right before your executable to launch MPI jobs.'))
    help.addArgument('MPI', '-with-mpi-compilers=<bool>',                        nargs.ArgBool(None, 1, 'Try to use the MPI compilers, e.g. mpicc'))
    help.addArgument('MPI', '-known-mpi-shared-libraries=<bool>',                nargs.ArgBool(None, None, 'Indicates the MPI libraries are shared (the usual test will be skipped)'))
    help.addArgument('MPI', '-with-mpi-f90module-visibility=<bool>',             nargs.ArgBool(None, 1, 'Indicates the MPI f90 module is available via petsc module. When disabled, mpi_f08 can be used from user code'))
    return

  def setupDependencies(self, framework):
    config.package.Package.setupDependencies(self, framework)
    self.mpich   = framework.require('config.packages.MPICH', self)
    self.openmpi = framework.require('config.packages.OpenMPI', self)
    self.cuda    = framework.require('config.packages.cuda',self)
    self.hip     = framework.require('config.packages.hip',self)
    self.sycl    = framework.require('config.packages.sycl',self)
    self.odeps   = [self.cuda,self.hip,self.sycl]
    return

  def __str__(self):
    output  = config.package.Package.__str__(self)
    if self.mpiexec: output  += '  mpiexec: '+self.mpiexec+'\n'
    if self.mpiexec_tail: output  += '  mpiexec_tail: '+self.mpiexec_tail+'\n'
    if self.mpi_pkg: output  += '  Implementation: '+self.mpi_pkg+'\n'
    if hasattr(self,'includepaths'):
      output  += '  MPI C++ include paths: '+ self.includepaths+'\n'
      output += '  MPI C++ libraries: '+ self.libpaths + ' ' + self.mpilibs+'\n'
    return output+self.mpi_pkg_version

  def generateLibList(self, directory):
    if self.setCompilers.usedMPICompilers:
      self.liblist = []
      self.libDirs = ['']
    return config.package.Package.generateLibList(self,directory)

  # search many obscure locations for MPI
  def getSearchDirectories(self):
    import re
    if self.mpich.found:
      yield (self.mpich.installDir)
      raise RuntimeError('--download-mpich libraries cannot be used')
    if self.openmpi.found:
      yield (self.openmpi.installDir)
      raise RuntimeError('--download-openmpi libraries cannot be used')

    yield ''
    # Try configure package directories
    dirExp = re.compile(r'mpi(ch)?(-.*)?')
    for packageDir in self.argDB['with-packages-search-path']:
      packageDir = os.path.abspath(packageDir)
      if not os.path.isdir(packageDir):
        raise RuntimeError('Invalid package directory: '+packageDir)
      for f in os.listdir(packageDir):
        dir = os.path.join(packageDir, f)
        if not os.path.isdir(dir):
          continue
        if not dirExp.match(f):
          continue
        yield (dir)
    # Try SUSE location
    yield (os.path.abspath(os.path.join('/opt', 'mpich')))
    # Try IBM
    self.isPOE = 1
    dir = os.path.abspath(os.path.join('/usr', 'lpp', 'ppe.poe'))
    yield (os.path.abspath(os.path.join('/usr', 'lpp', 'ppe.poe')))
    self.isPOE = 0
    # Try /usr/local
    yield (os.path.abspath(os.path.join('/usr', 'local')))
    # Try /usr/local/*mpich*
    if os.path.isdir(dir):
      ls = os.listdir(dir)
      for dir in ls:
        if dir.find('mpich') >= 0:
          dir = os.path.join('/usr','local',dir)
          if os.path.isdir(dir):
            yield (dir)
    # Try ~/mpich*
    homedir = os.getenv('HOME')
    if homedir:
      ls = os.listdir(homedir)
      for dir in ls:
        if dir.find('mpich') >= 0:
          dir = os.path.join(homedir,dir)
          if os.path.isdir(dir):
            yield (dir)
    # Try MSMPI/MPICH install locations under Windows
    # ex: /cygdrive/c/Program Files/Microsoft HPC Pack 2008 SDK
    for root in ['/',os.path.join('/','cygdrive')]:
      for drive in ['c']:
        for programFiles in ['Program Files','Program Files (x86)']:
          for packageDir in ['Microsoft HPC Pack 2008 SDK','Microsoft Compute Cluster Pack','MPICH2','MPICH',os.path.join('MPICH','SDK.gcc'),os.path.join('MPICH','SDK')]:
            yield(os.path.join(root,drive,programFiles,packageDir))
    return

  def checkSharedLibrary_ThisIsBroken(self):
  # TODO: Fix this routine, currently
  #       * the visibility flag is passed to the compiling/linking so the symbols are not visible to the loader and the test fails (this is easily fixed)
  #       * even with that fixed the dlsym() is unable to locate the checkInit symbol in the library even though nm shows it is there; I am not sure the cause
    '''Sets flag indicating if MPI libraries are shared or not and
    determines if MPI libraries CANNOT be used by shared libraries'''
    if self.argDB['with-batch']:
      if self.argDB['with-shared-libraries']:
        if not 'known-mpi-shared-libraries' in self.argDB:
          self.logPrintWarning('Cannot verify that MPI is a shared library - in \
batch-mode! If MPI is a static library but linked into multiple shared \
libraries that the application uses, sometimes compiles work - \
but one might get run-time errors. If you know that the MPI library is \
shared - run with --known-mpi-shared-libraries=1 option to remove this \
warning message')
        elif not self.argDB['known-mpi-shared-libraries']:
          raise RuntimeError('Provided MPI library is flagged as static library! If its linked\n\
into multiple shared libraries that an application uses, sometimes\n\
compiles go through - but one might get run-time errors.  Either\n\
reconfigure PETSc with --with-shared-libraries=0 or provide MPI with\n\
shared libraries and run with --known-mpi-shared-libraries=1')
      return
    self.shared = self.libraries.checkShared('#include <mpi.h>\n','MPI_Init','MPI_Initialized','MPI_Finalize',checkLink = self.checkPackageLink,libraries = self.lib, defaultArg = 'known-mpi-shared-libraries', executor = self.mpiexecseq)

    # TODO: Turn this on once shared library checks are working again
    #if self.argDB['with-shared-libraries'] and not self.shared:
    #  self.logPrint('MPI libraries cannot be used with shared libraries')
    #  raise RuntimeError('Shared libraries cannot be built using MPI provided.\nEither reconfigure with --with-shared-libraries=0 or rebuild MPI with shared library support')
    return

  def configureMPIEXEC_TAIL(self):
    '''Checking for location of mpiexec_tail'''
    if 'with-mpiexec-tail' in self.argDB:
      self.argDB['with-mpiexec-tail'] = os.path.expanduser(self.argDB['with-mpiexec-tail'])
      # If found, the call below defines a make macro MPIEXEC_TAIL with full path
      if not self.getExecutable(self.argDB['with-mpiexec-tail'], getFullPath=1, resultName = 'mpiexec_tail'):
        raise RuntimeError('Invalid mpiexec-tail specified: '+str(self.argDB['with-mpiexec-tail']))
    else:
      self.mpiexec_tail =''
      self.addMakeMacro('MPIEXEC_TAIL', '')

  def configureMPIEXEC(self):
    '''Checking for location of mpiexec'''
    mpiexecargs = ''
    if self.argDB['with-batch']:
      if 'with-mpiexec' in self.argDB:
        self.logPrintBox('--with-mpiexec is ignored since --with-batch is provided; one cannot run generated executables on the compile server')
      self.mpiexec = 'Not_appropriate_for_batch_systems_You_must_use_your_batch_system_to_submit_MPI_jobs_speak_with_your_local_sys_admin'
      self.mpiexecseq = 'Not_appropriate_for_batch_systems_You_must_use_your_batch_system_to_submit_MPI_jobs_speak_with_your_local_sys_admin'
      self.addMakeMacro('MPIEXEC', self.mpiexec)
      return
    if 'with-mpiexec' in self.argDB:
      self.argDB['with-mpiexec'] = os.path.expanduser(self.argDB['with-mpiexec'])
      if not self.getExecutable(self.argDB['with-mpiexec'], resultName = 'mpiexec'):
        raise RuntimeError('Invalid mpiexec specified: '+str(self.argDB['with-mpiexec']))
      self.mpiexec = self.argDB['with-mpiexec']
    elif self.isPOE:
      self.mpiexec = os.path.abspath(os.path.join('bin', 'mpiexec.poe'))
    else:
      mpiexecs = ['mpiexec', 'mpirun', 'mprun', 'srun']
      path    = []
      if 'with-mpi-dir' in self.argDB:
        path.append(os.path.join(os.path.abspath(self.argDB['with-mpi-dir']), 'bin'))
        # MPICH-NT-1.2.5 installs MPIRun.exe in mpich/mpd/bin
        path.append(os.path.join(os.path.abspath(self.argDB['with-mpi-dir']), 'mpd','bin'))
        useDefaultPath = 0
      else:
        for inc in self.include:
          path.append(os.path.join(os.path.dirname(inc), 'bin'))
          # MPICH-NT-1.2.5 installs MPIRun.exe in mpich/SDK/include/../../mpd/bin
          path.append(os.path.join(os.path.dirname(os.path.dirname(inc)),'mpd','bin'))
        for lib in self.lib:
          path.append(os.path.join(os.path.dirname(os.path.dirname(lib)), 'bin'))
        self.pushLanguage('C')
        if (os.path.basename(self.getCompiler()) == 'mpicc' or os.path.basename(self.getCompiler()) == 'mpiicc'):
          if os.path.dirname(self.getCompiler()):
            path.append(os.path.dirname(self.getCompiler()))
          else:
            try:
              (out,err,status) = config.base.Configure.executeShellCommand('which '+self.getCompiler())
              if not status and not err:
                path.append(os.path.dirname(out))
            except:
              pass
        self.popLanguage()
        useDefaultPath = 1
      if not self.getExecutable(mpiexecs, path = path, useDefaultPath = useDefaultPath, resultName = 'mpiexec',setMakeMacro=0):
        if not self.getExecutable('/bin/false', path = [], useDefaultPath = 0, resultName = 'mpiexec',setMakeMacro=0):
          raise RuntimeError('Could not locate MPIEXEC - please specify --with-mpiexec option')
      # Support for spaces and () in executable names; also needs to handle optional arguments at the end
      # TODO: This support for spaces and () should be moved to core BuildSystem
      self.mpiexec = self.mpiexec.replace(' ', r'\\ ').replace('(', r'\\(').replace(')', r'\\)').replace(r'\ -',' -')
      if hasattr(self, 'ompi_major_version'):
        if int(self.ompi_major_version) >= 5:
          mpiexecargs += ' --oversubscribe' # alias to --map-by :OVERSUBSCRIBE
        elif int(self.ompi_major_version) >= 3:
          (out, err, ret) = Configure.executeShellCommand(self.mpiexec+' -help all', checkCommand = noCheck, timeout = 60, log = self.log, threads = 1)
          if out.find('--oversubscribe') >=0:
            mpiexecargs += ' --oversubscribe'

    self.getExecutable(self.mpiexec, getFullPath=1, resultName='mpiexecExecutable',setMakeMacro=0)

    if not 'with-mpiexec' in self.argDB and hasattr(self,'isNecMPI') and hasattr(self,'mpiexecExecutable'):
      self.getExecutable('venumainfo', getFullPath=1, path = os.path.dirname(self.mpiexecExecutable))
      if hasattr(self,'venumainfo'):
        try:
          (out, err, ret) = Configure.executeShellCommand(self.venumainfo + ' | grep "available"',timeout = 60, log = self.log, threads = 1)
        except Exception as e:
          self.logWrite('NEC utility venumainfo failed '+str(e)+'\n')
        else:
          try:
            nve = len(out.split('\n'))
            mpiexecargs += ' -nve ' + str(nve)
          except Exception as e:
            self.logWrite('Unable to parse the number of VEs from the NEC utility venumainfo\n'+str(e)+'\n')

    # using mpiexec environmental variables make sure mpiexec matches the MPI libraries and save the variables for testing in PetscInitialize()
    # the variable HAVE_MPIEXEC_ENVIRONMENTAL_VARIABLE is not currently used. PetscInitialize() can check the existence of the environmental variable to
    # determine if the program has been started with the correct mpiexec (will only be set for parallel runs so not clear how to check appropriately)
    (out, err, ret) = Configure.executeShellCommand(self.mpiexec+' -n 1 printenv', checkCommand = noCheck, timeout = 120, threads = 1, log = self.log)
    if ret:
      self.logWrite('Unable to run '+self.mpiexec+' with option "-n 1 printenv"\nThis could be ok, some MPI implementations such as SGI produce a non-zero status with non-MPI programs\n'+out+err)
    else:
      if out.find('MPIR_CVAR_CH3') > -1:
        if hasattr(self,'ompi_major_version'): raise RuntimeError("Your libraries are from Open MPI but it appears your mpiexec is from MPICH");
        self.addDefine('HAVE_MPIEXEC_ENVIRONMENTAL_VARIABLE', 'MPIR_CVAR_CH3')
      elif  out.find('MPIR_CVAR_CH3') > -1:
        if hasattr(self,'ompi_major_version'): raise RuntimeError("Your libraries are from Open MPI but it appears your mpiexec is from MPICH");
        self.addDefine('HAVE_MPIEXEC_ENVIRONMENTAL_VARIABLE', 'MPICH')
      elif out.find('OMPI_COMM_WORLD_SIZE') > -1:
        if hasattr(self,'mpich_numversion'): raise RuntimeError("Your libraries are from MPICH but it appears your mpiexec is from Open MPI");
        self.addDefine('HAVE_MPIEXEC_ENVIRONMENTAL_VARIABLE', 'OMP')
    if hasattr(self,'isNecMPI'):
      (out, err, ret) = Configure.executeShellCommand(self.mpiexec+' -n 1 -V /usr/bin/true', checkCommand = noCheck, timeout = 120, threads = 1, log = self.log)
      if ret:
        self.logWrite('Unable to run '+self.mpiexec+' with option "-n 1 -V /usr/bin/true"\n'+str(out)+'\n'+str(err))
      else:
        try:
          necmpimajor = out.split(' ')[4].split('.')[0]
          necmpiminor = out.split(' ')[4].split('.')[1]
          self.addDefine('NECMPI_VERSION_MAJOR', necmpimajor)
          self.addDefine('NECMPI_VERSION_MINOR', necmpiminor)
        except Exception as e:
            self.logWrite('Unable to parse the output of '+self.mpiexec+' with option "-n 1 -V /usr/bin/true"\n'+str(e)+'\n'+str(out)+'\n'+str(err))

    # use full path if found
    if self.mpiexecExecutable:
      self.mpiexec = self.mpiexecExecutable
    self.addMakeMacro('MPIEXEC', self.mpiexec + mpiexecargs)

    # use sequential runs for testing
    self.mpiexecseq = self.mpiexec + mpiexecargs + ' -n 1'

    if hasattr(self,'mpich_numversion') or hasattr(self,'ompi_major_version'):

      hostnameworks = 0
      # turn of checks if Apple firewall is on since it prevents success of the tests even though MPI will work
      self.getExecutable('socketfilterfw', path = ['/usr/libexec/ApplicationFirewall'])
      if hasattr(self,'socketfilterfw'):
        try:
          (result, err, ret) = Configure.executeShellCommand(self.socketfilterfw + ' --getglobalstate', timeout = 60, log = self.log, threads = 1)
          if result.find("Firewall is enabled") > -1:  hostnameworks = 1
        except:
          self.logPrint("Exception: Unable to get result from socketfilterfw\n")

      self.getExecutable('hostname')
      if not hostnameworks and hasattr(self,'hostname'):
        try:
          (hostname, err, ret) = Configure.executeShellCommand(self.hostname, timeout = 60, log = self.log, threads = 1)
          self.logPrint("Return code from hostname: %s\n" % ret)
        except:
          self.logPrint("Exception: Unable to get result from hostname, skipping network checks\n")
        else:
          if ret == 0:
            self.logPrint("Hostname works, running network checks")

            self.getExecutable('ping', path = ['/sbin'], useDefaultPath = 1)
            if not hasattr(self,'ping'):
              self.getExecutable('fping', resultName = 'ping')
            if hasattr(self,'ping'):
              if self.setCompilers.isCygwin(self.log):
                count = ' -n 2 '
              else:
                count = ' -c 2 '
              try:
                (ok, err, ret) = Configure.executeShellCommand(self.ping + count + hostname, timeout = 60, log = self.log, threads = 1)
                self.logPrint("Return code from ping: %s\n" % ret)
                if not ret: hostnameworks = 1
              except:
                self.logPrint("Exception: while running ping skipping ping check\n")

              if not hostnameworks:
                # Note: host may not work on macOS, this is normal
                self.getExecutable('host')
                if hasattr(self,'host'):
                  try:
                    (ok, err, ret) = Configure.executeShellCommand(self.host + ' '+ hostname, timeout = 60, log = self.log, threads = 1)
                    self.logPrint("Return code from host: %s\n" % ret)
                    # host works even with broken VPN it is not a useful test
                  except:
                    self.logPrint("Exception: while running host skipping host check\n")

              if not hostnameworks:
                self.getExecutable('traceroute', path = ['/usr/sbin'], useDefaultPath = 1)
                if hasattr(self,'traceroute'):
                  try:
                    (ok, err, ret) = Configure.executeShellCommand(self.traceroute + ' ' + hostname, timeout = 60, log = self.log, threads = 1)
                    self.logPrint("Return code from traceroute: %s\n" % ret)
                    if not ret: hostnameworks = 1
                  except:
                    self.logPrint("Exception: while running traceroute skipping traceroute check\n")

              if not hostnameworks:
                self.logPrintWarning('mpiexec may not work on your system due to network issues. \
Perhaps you have VPN running whose network settings may not work with mpiexec or your network is misconfigured')
          else:
            self.logPrintWarning('mpiexec may not work on your system due to network issues. \
Unable to run hostname to check the network')
          self.logPrintDivider()

    # check that mpiexec runs an MPI program correctly
    error_message = 'Unable to run MPI program with '+self.mpiexecseq+'\n\
    (1) make sure this is the correct program to run MPI jobs\n\
    (2) your network may be misconfigured; see https://petsc.org/release/faq/#mpi-network-misconfigure\n\
    (3) you may have VPN running whose network settings may not play nice with MPI\n'

    includes = '#include <mpi.h>'
    body = 'MPI_Init(0,0);\nMPI_Finalize();\n'
    try:
      ok = self.checkRun(includes, body, executor = self.mpiexecseq, timeout = 120, threads = 1)
      if not ok: raise RuntimeError(error_message)
    except RuntimeError as e:
      if str(e).find('Runaway process exceeded time limit') > -1:
        raise RuntimeError('Timeout: %s' % error_message)

  def configureMPI2(self):
    '''Check for functions added to the interface in MPI-2'''
    oldFlags = self.compilers.CPPFLAGS
    oldLibs  = self.compilers.LIBS
    self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)
    self.compilers.LIBS = self.libraries.toString(self.lib)+' '+self.compilers.LIBS
    self.framework.saveLog()
    # Check for some of the MPI functions PETSc needs from MPI-2.0/2.1. Generally speaking, PETSc requires MPI-2.1 with exception of MPI multithreading and one-sided.
    if not self.checkLink('#include <mpi.h>\n',
    '''
      int a,b,c,d,flag,sendbuf[1]={1},recvbuf[1]={2};
      MPI_Datatype newtype;
      if (MPI_Allreduce(MPI_IN_PLACE,0,1,MPI_INT,MPI_SUM,MPI_COMM_SELF)) return 0;
      if (MPI_Finalized(&flag)) return 0;
      if (MPI_Type_dup(MPI_INT,&newtype)) return 0;
      if (MPI_Exscan(sendbuf,recvbuf,1,MPI_INT,MPI_SUM,MPI_COMM_WORLD)) return 0;
      if (MPI_Reduce_scatter(sendbuf,recvbuf,sendbuf,MPI_INT,MPI_SUM,MPI_COMM_WORLD)) return 0;
      if (MPI_Type_get_envelope(MPI_INT,&a,&b,&c,&d)) return 0;
    '''):
      raise RuntimeError('PETSc requires some of the MPI-2.0 (1997), MPI-2.1 (2008) functions - they are not available with the specified MPI library')

    if not self.checkLink('#include <mpi.h>\n', 'int count=2; int blocklens[2]={0,1}; MPI_Aint indices[2]={0,1}; MPI_Datatype old_types[2]={MPI_INT,MPI_DOUBLE}; MPI_Datatype *newtype = 0;\n \
                                             if (MPI_Type_create_struct(count, blocklens, indices, old_types, newtype)) { }\n'):
      self.framework.addDefine('MPI_Type_create_struct(count,lens,displs,types,newtype)', 'MPI_Type_struct((count),(lens),(displs),(types),(newtype))')
    if not self.checkLink('#include <mpi.h>\n', 'MPI_Comm_errhandler_fn * p_err_fun = 0; MPI_Errhandler * p_errhandler = 0; if (MPI_Comm_create_errhandler(p_err_fun,p_errhandler)) { }\n'):
      self.framework.addDefine('MPI_Comm_create_errhandler(p_err_fun,p_errhandler)', 'MPI_Errhandler_create((p_err_fun),(p_errhandler))')
    if not self.checkLink('#include <mpi.h>\n', 'if (MPI_Comm_set_errhandler(MPI_COMM_WORLD,MPI_ERRORS_RETURN)) { }\n'):
      self.framework.addDefine('MPI_Comm_set_errhandler(comm,p_errhandler)', 'MPI_Errhandler_set((comm),(p_errhandler))')
    if self.checkLink('#include <mpi.h>\n', 'if (MPI_Reduce_local(0, 0, 0, MPI_INT, MPI_SUM)) { }\n'): # MPI_Reduce_local is in MPI-2.2
      self.haveReduceLocal = 1
      self.addDefine('HAVE_MPI_REDUCE_LOCAL',1)
    if self.checkLink('#include <mpi.h>\n', 'char version[MPI_MAX_LIBRARY_VERSION_STRING];int verlen;if (MPI_Get_library_version(version,&verlen)) { }\n'):
      self.addDefine('HAVE_MPI_GET_LIBRARY_VERSION', 1)
    # Even MPI_Win_create is in MPI 2.0, we do this test to suppress MPIUNI, which does not support MPI one-sided.
    if self.checkLink('#include <mpi.h>\n', 'int base[100]; MPI_Win win = 0; if (MPI_Win_create(base,100,4,MPI_INFO_NULL,MPI_COMM_WORLD,&win)) { }'):
      self.addDefine('HAVE_MPI_WIN_CREATE', 1)
    if not self.checkLink('#include <mpi.h>\n', 'int ptr[1] = {0}; MPI_Win win = 0; if (MPI_Accumulate(ptr,1,MPI_INT,0,0,1,MPI_INT,MPI_REPLACE,win)) { }'):
      raise RuntimeError('PETSc requires MPI_REPLACE (introduced in MPI-2.1 in 2008). Please update or switch to MPI that supports MPI_REPLACE. Let us know at petsc-maint@mcs.anl.gov if this is not possible')
    # flag broken one-sided tests
    if not 'HAVE_MSMPI' in self.defines and not (hasattr(self, 'mpich_numversion') and int(self.mpich_numversion) <= 30004300) and not (hasattr(self, 'isNecMPI')):
      self.addDefine('HAVE_MPI_ONE_SIDED', 1)

    if self.checkLink('#include <mpi.h>\n', 'int provided; if (MPI_Init_thread(0,0,MPI_THREAD_FUNNELED,&provided)) return 0;'): # MPI-2.1
      self.addDefine('HAVE_MPI_INIT_THREAD',1)

    # deadlock AO tests ex1 with test 3
    if (not hasattr(self, 'isNecMPI')) and self.checkLink('#include <mpi.h>\n',
    '''
     int sendbuf[2] = {1,2};
     int recvbuf[1];
     if (MPI_Reduce_scatter_block(sendbuf,recvbuf,1,MPI_INT,MPI_SUM,MPI_COMM_WORLD)) return 0;
    '''):
      self.addDefine('HAVE_MPI_REDUCE_SCATTER_BLOCK',1) # MPI-2.2

    self.compilers.CPPFLAGS = oldFlags
    self.compilers.LIBS = oldLibs
    self.logWrite(self.framework.restoreLog())
    return

  def configureMPI3(self):
    '''Check for functions added to the interface in MPI-3'''
    oldFlags = self.compilers.CPPFLAGS
    oldLibs  = self.compilers.LIBS
    self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)
    self.compilers.LIBS = self.libraries.toString(self.lib)+' '+self.compilers.LIBS
    self.framework.saveLog()
    # Skip buggy MPICH versions
    if (hasattr(self, 'mpich_numversion') and int(self.mpich_numversion) > 30004300) or not hasattr(self, 'mpich_numversion'):
      if self.checkLink('#include <mpi.h>\n',
                      'MPI_Comm scomm; MPI_Aint size=128; int disp_unit=8,*baseptr; MPI_Win win;\n\
                       if (MPI_Comm_split_type(MPI_COMM_WORLD, MPI_COMM_TYPE_SHARED, 0, MPI_INFO_NULL, &scomm)) { }\n\
                       if (MPI_Win_allocate_shared(size,disp_unit,MPI_INFO_NULL,MPI_COMM_WORLD,&baseptr,&win)) { }\n\
                       if (MPI_Win_shared_query(win,0,&size,&disp_unit,&baseptr)) { }\n'):
        self.addDefine('HAVE_MPI_PROCESS_SHARED_MEMORY', 1)
        self.support_mpi3_shm = 1
    if not any([
        hasattr(self, 'isIntelMPI'),
        hasattr(self, 'ompi_version') and (4,1,0) <= self.ompi_version < (4,2,0), # dynamic window tests fail unless using --mca btl vader
        ]) and self.checkLink('#include <mpi.h>\n',
                      'MPI_Aint size=128; int disp_unit=8,*baseptr; MPI_Win win;\n\
                       if (MPI_Win_allocate(size,disp_unit,MPI_INFO_NULL,MPI_COMM_WORLD,&baseptr,&win)) { }\n\
                       if (MPI_Win_attach(win,baseptr,size)) { }\n\
                       if (MPI_Win_create_dynamic(MPI_INFO_NULL,MPI_COMM_WORLD,&win)) { }\n'):
      self.addDefine('HAVE_MPI_FEATURE_DYNAMIC_WINDOW', 1) # Use it to represent a group of MPI3 Win routines
    if self.checkCompile('#include <mpi.h>\n MPI_Count i = 0;\n'): # introduced in MPI-3.0
      self.addDefine('HAVE_MPI_COUNT',1) # we need it to support MPIPetsc_Type_get_envelope etc

    if self.checkLink('#include <mpi.h>\n',
                      '''
                        int send=0,recv,counts[2]={1,1},displs[2]={1,2}; MPI_Request req;
                        if (MPI_Iscatter(&send,1,MPI_INT,&recv,1,MPI_INT,0,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Iscatterv(&send,counts,displs,MPI_INT,&recv,1,MPI_INT,0,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Igather(&send,1,MPI_INT,&recv,1,MPI_INT,0,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Igatherv(&send,1,MPI_INT,&recv,counts,displs,MPI_INT,0,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Iallgather(&send,1,MPI_INT,&recv,1,MPI_INT,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Iallgatherv(&send,1,MPI_INT,&recv,counts,displs,MPI_INT,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Ialltoall(&send,1,MPI_INT,&recv,1,MPI_INT,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Iallreduce(&send,&recv,1,MPI_INT,MPI_SUM,MPI_COMM_WORLD,&req)) return 0;
                        if (MPI_Ibarrier(MPI_COMM_WORLD,&req)) return 0;
                      '''):
      self.addDefine('HAVE_MPI_NONBLOCKING_COLLECTIVES', 1)
    if self.checkLink('#include <mpi.h>\n',
                      'MPI_Comm distcomm; \n\
                       MPI_Request req; \n\
                       if (MPI_Dist_graph_create_adjacent(MPI_COMM_WORLD,0,0,MPI_WEIGHTS_EMPTY,0,0,MPI_WEIGHTS_EMPTY,MPI_INFO_NULL,0,&distcomm)) { }\n\
                       if (MPI_Neighbor_alltoallv(0,0,0,MPI_INT,0,0,0,MPI_INT,distcomm)) { }\n\
                       if (MPI_Ineighbor_alltoallv(0,0,0,MPI_INT,0,0,0,MPI_INT,distcomm,&req)) { }\n'):
      self.addDefine('HAVE_MPI_NEIGHBORHOOD_COLLECTIVES',1)
    cuda_aware = 0
    if hasattr(self, 'ompi_major_version'):
      openmpi_cuda_test = '#include<mpi.h>\n #include <mpi-ext.h>\n #if defined(MPIX_CUDA_AWARE_SUPPORT) && MPIX_CUDA_AWARE_SUPPORT\n #else\n #error This Open MPI is not CUDA-aware\n #endif\n'
      if self.checkCompile(openmpi_cuda_test):
        cuda_aware = 1
    elif hasattr(self, 'mpich_numversion'):
      if self.libraries.check(self.dlib, "yaksuri_cudai_unpack_wchar_t"):
        cuda_aware = 1
    if cuda_aware:
      self.addDefine('HAVE_MPI_GPU_AWARE', 1)
    else:
      self.testoptions = '-use_gpu_aware_mpi 0'
    if self.checkLink('#include <mpi.h>\n', 'int ptr[1] = {0}; MPI_Win win = 0; if (MPI_Get_accumulate(ptr,1,MPI_INT,ptr,1,MPI_INT,0,0,1,MPI_INT,MPI_SUM,win)) { }\n'):
      self.addDefine('HAVE_MPI_GET_ACCUMULATE', 1)
    if self.checkLink('#include <mpi.h>\n', 'int ptr[1]; MPI_Win win = 0; MPI_Request req; if (MPI_Rget(ptr,1,MPI_INT,0,1,1,MPI_INT,win,&req)) { }\n'):
      self.addDefine('HAVE_MPI_RGET', 1)
    self.compilers.CPPFLAGS = oldFlags
    self.compilers.LIBS = oldLibs
    self.logWrite(self.framework.restoreLog())
    return


  def configureMPI4(self):
    '''Check for functions added to the interface in MPI-4'''
    oldFlags = self.compilers.CPPFLAGS
    oldLibs  = self.compilers.LIBS
    self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)
    self.compilers.LIBS = self.libraries.toString(self.lib)+' '+self.compilers.LIBS
    self.framework.saveLog()

    if self.checkLink('#include <mpi.h>\n',
    '''
      int          buf[1]={0},dest=1,source=1,tag=0, combiner, ints[1];
      MPI_Count    count=1, nints, naddrs, ncounts, ntypes, counts[1];
      MPI_Request  req;
      MPI_Status   stat;
      MPI_Aint     addrs[1];
      MPI_Datatype types[1];

      if (MPI_Send_c(buf,count,MPI_INT,dest,tag,MPI_COMM_WORLD)) return 1;
      if (MPI_Send_init_c(buf,count,MPI_INT,dest,tag,MPI_COMM_WORLD,&req)) return 1;
      if (MPI_Isend_c(buf,count,MPI_INT,dest,tag,MPI_COMM_WORLD,&req)) return 1;
      if (MPI_Recv_c(buf,count,MPI_INT,source,tag,MPI_COMM_WORLD,&stat)) return 1;
      if (MPI_Recv_init_c(buf,count,MPI_INT,source,tag,MPI_COMM_WORLD,&req)) return 1;
      if (MPI_Irecv_c(buf,count,MPI_INT,source,tag,MPI_COMM_WORLD,&req)) return 1;
      if (MPI_Neighbor_alltoallv_c(0,0,0,MPI_INT,0,0,0,MPI_INT,MPI_COMM_WORLD)) return 1;
      if (MPI_Ineighbor_alltoallv_c(0,0,0,MPI_INT,0,0,0,MPI_INT,MPI_COMM_WORLD,&req)) return 1;
      if (MPI_Type_get_envelope_c(MPI_INT,&nints,&naddrs,&ncounts,&ntypes,&combiner)) return 1;
      if (MPI_Type_get_contents_c(MPI_INT,nints,naddrs,ncounts,ntypes,ints,addrs,counts,types)) return 1;
    ''' + ('if (MPI_Reduce_local_c(0,0,0,MPI_INT,MPI_SUM)) return 1;\n' if self.haveReduceLocal == 1 else '')):
      self.addDefine('HAVE_MPI_LARGE_COUNT', 1)

    if self.checkLink('#include <mpi.h>\n',
    '''
      MPI_Request req;
      MPI_Info    info = 0;
      if (MPI_Neighbor_alltoallv_init(0,0,0,MPI_INT,0,0,0,MPI_INT,MPI_COMM_WORLD,info,&req)) return 1;
    '''):
      self.addDefine('HAVE_MPI_PERSISTENT_NEIGHBORHOOD_COLLECTIVES', 1)

    self.compilers.CPPFLAGS = oldFlags
    self.compilers.LIBS = oldLibs
    self.logWrite(self.framework.restoreLog())
    return

  def configureMPIX(self):
    '''Check for experimental functions added by MPICH or Open MPI as MPIX'''
    # mpich-4.2 has a bug fix (PR6454). Without it, we could not use MPIX stream
    if (hasattr(self, 'mpich_numversion') and int(self.mpich_numversion) >= 40200000):
      oldFlags = self.compilers.CPPFLAGS
      oldLibs  = self.compilers.LIBS
      self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)
      self.compilers.LIBS = self.libraries.toString(self.lib)+' '+self.compilers.LIBS
      self.framework.saveLog()
      if self.checkLink('#include <mpi.h>\n',
      '''
        MPI_Info    info ;
        // cudaStream_t stream;
        int         stream; // use a fake type instead as we don't want this check to depend on CUDA
        MPI_Comm    stream_comm ;
        MPIX_Stream mpi_stream ;
        MPI_Request req;
        MPI_Status  stat;
        int         sbuf[1]={0},rbuf[1]={0},count=1,dest=1,source=0,tag=0;

        MPI_Info_create (&info);
        MPI_Info_set(info, "type", "cudaStream_t");
        MPIX_Info_set_hex(info, "value", &stream, sizeof(stream));
        MPIX_Stream_create(info, &mpi_stream );
        MPIX_Stream_comm_create(MPI_COMM_WORLD, mpi_stream, &stream_comm);
        MPIX_Isend_enqueue(sbuf,count,MPI_INT,dest,tag,stream_comm,&req);
        MPIX_Irecv_enqueue(rbuf,count,MPI_INT,source,tag,stream_comm,&req);
        MPIX_Allreduce_enqueue(sbuf,rbuf,count,MPI_INT,MPI_SUM,stream_comm);
        MPIX_Wait_enqueue(&req, &stat);
      '''):
        self.addDefine('HAVE_MPIX_STREAM', 1)

      if self.checkLink('#include <mpi.h>\n',
      '''
        MPI_Comm comm = MPI_COMM_WORLD; // fake
        MPIX_Threadcomm_start(comm);
        MPIX_Threadcomm_finish(comm);
        MPIX_Threadcomm_free(&comm);
      '''):
        self.addDefine('HAVE_MPIX_THREADCOMM', 1)

      self.compilers.CPPFLAGS = oldFlags
      self.compilers.LIBS = oldLibs
      self.logWrite(self.framework.restoreLog())
    return

  def configureMPITypes(self):
    '''Checking for MPI Datatype handles'''
    oldFlags = self.compilers.CPPFLAGS
    oldLibs  = self.compilers.LIBS
    self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)
    self.compilers.LIBS = self.libraries.toString(self.lib)+' '+self.compilers.LIBS
    mpitypes = [('MPI_LONG_DOUBLE', 'long-double'), ('MPI_INT64_T', 'int64_t')]
    for datatype, name in mpitypes:
      includes = '#include <stdlib.h>\n#include <mpi.h>\n'
      body     = 'int size;\nint ierr;\nMPI_Init(0,0);\nierr = MPI_Type_size('+datatype+', &size);\nif(ierr || (size == 0)) exit(1);\nMPI_Finalize();\n'
      if self.checkCompile(includes, body):
        self.addDefine('HAVE_'+datatype, 1)
    self.compilers.CPPFLAGS = oldFlags
    self.compilers.LIBS = oldLibs
    return

  def alternateConfigureLibrary(self):
    '''Setup MPIUNI, our uniprocessor version of MPI'''
    self.addDefine('HAVE_MPIUNI', 1)
    self.addDefine('HAVE_MPI_REDUCE_LOCAL',1) # One can add these MPI macros on demand for MPIUNI
    self.addDefine('HAVE_MPI_LARGE_COUNT', 1)
    self.addDefine('HAVE_MPI_COUNT',1)
    self.addMakeMacro('MPI_IS_MPIUNI', 1)
    self.framework.packages.append(self)
    self.mpiexec = '${PETSC_DIR}/lib/petsc/bin/petsc-mpiexec.uni'
    self.mpiexecseq = '${PETSC_DIR}/lib/petsc/bin/petsc-mpiexec.uni'
    self.addMakeMacro('MPIEXEC','${PETSC_DIR}/lib/petsc/bin/petsc-mpiexec.uni')
    self.executeTest(self.configureMPIEXEC_TAIL)
    self.framework.saveLog()
    self.framework.addDefine('MPI_Type_create_struct(count,lens,displs,types,newtype)', 'MPI_Type_struct((count),(lens),(displs),(types),(newtype))')
    self.framework.addDefine('MPI_Comm_create_errhandler(p_err_fun,p_errhandler)', 'MPI_Errhandler_create((p_err_fun),(p_errhandler))')
    self.framework.addDefine('MPI_Comm_set_errhandler(comm,p_errhandler)', 'MPI_Errhandler_set((comm),(p_errhandler))')
    self.logWrite(self.framework.restoreLog())
    self.usingMPIUni = 1
    self.found = 1
    self.version = 'PETSc MPIUNI uniprocessor MPI replacement'
    self.executeTest(self.PetscArchMPICheck)
    return

  def checkDownload(self):
    '''Check if we should download MPICH or Open MPI'''
    if 'download-mpi' in self.argDB and self.argDB['download-mpi']:
      raise RuntimeError('Option --download-mpi does not exist! Use --download-mpich or --download-openmpi instead.')
    if self.argDB['download-mpich'] and self.argDB['download-openmpi']:
      raise RuntimeError('Cannot install more than one of Open MPI or  MPICH for a single configuration. \nUse different PETSC_ARCH if you want to be able to switch between two')
    return None

  def SGIMPICheck(self):
    '''Returns true if SGI MPI is used'''
    if self.libraries.check(self.lib, 'MPI_SGI_barrier') :
      self.logPrint('SGI MPI detected - defining MISSING_SIGTERM')
      self.addDefine('MISSING_SIGTERM', 1)
      return 1
    else:
      self.logPrint('SGI MPI test failure')
      return 0

  def CxxMPICheck(self):
    '''Make sure C++ can compile and link'''
    if not hasattr(self.compilers, 'CXX'):
      return 0
    self.libraries.pushLanguage('Cxx')
    oldFlags = self.compilers.CXXPPFLAGS
    self.compilers.CXXPPFLAGS += ' '+self.headers.toString(self.include)
    self.log.write('Checking for header mpi.h\n')
    # check if MPI_Finalize from c++ exists
    self.log.write('Checking for C++ MPI_Finalize()\n')
    if not self.libraries.check(self.lib, 'MPI_Finalize', prototype = '#include <mpi.h>', call = 'int ierr;\nierr = MPI_Finalize();\n(void)ierr', cxxMangle = 1):
      raise RuntimeError('C++ error! MPI_Finalize() could not be located!')
    self.compilers.CXXPPFLAGS = oldFlags
    self.libraries.popLanguage()
    return

  def FortranMPICheck(self):
    '''Make sure fortran include [mpif.h] and library symbols are found'''
    if not hasattr(self.compilers, 'FC'):
      return 0
    # Fortran compiler is being used - so make sure mpif.h exists
    self.libraries.pushLanguage('FC')
    oldFlags = self.compilers.FPPFLAGS
    self.compilers.FPPFLAGS += ' '+self.headers.toString(self.include)
    # check if mpi_init form fortran works
    self.log.write('Checking for fortran mpi_init()\n')
    if not self.libraries.check(self.lib,'', call = '#include "mpif.h"\n       integer ierr\n       call mpi_init(ierr)'):
      raise RuntimeError('Fortran error! mpi_init() could not be located!')
    # check if mpi.mod exists
    if self.fortran.fortranIsF90:
      self.log.write('Checking for mpi.mod\n')
      if self.libraries.check(self.lib,'', call = '       use mpi\n       integer(kind=selected_int_kind(5)) ierr,rank\n       call mpi_init(ierr)\n       call mpi_comm_rank(MPI_COMM_WORLD,rank,ierr)\n'):
        self.addDefine('HAVE_MPI_F90MODULE', 1)
    self.compilers.FPPFLAGS = oldFlags
    self.libraries.popLanguage()
    return 0

  def configureIO(self):
    '''Check for the functions in MPI/IO
       - Define HAVE_MPIIO if they are present
       - Some older MPI 1 implementations are missing these'''
    # MSWIN has buggy MPI IO
    if 'HAVE_MSMPI' in self.defines: return
    oldFlags = self.compilers.CPPFLAGS
    oldLibs  = self.compilers.LIBS
    self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)
    self.compilers.LIBS = self.libraries.toString(self.lib)+' '+self.compilers.LIBS
    if not self.checkLink('#include <mpi.h>\n', '''MPI_Aint lb, extent;\nif (MPI_Type_get_extent(MPI_INT, &lb, &extent)) { }\n
                                                 MPI_File fh = 0;\nvoid *buf = 0;\nMPI_Status status;\nif (MPI_File_write_all(fh, buf, 1, MPI_INT, &status)) { }\n
                                                 if (MPI_File_read_all(fh, buf, 1, MPI_INT, &status)) { }\n
                                                 MPI_Offset disp = 0;\nMPI_Info info = 0;\nif (MPI_File_set_view(fh, disp, MPI_INT, MPI_INT, "", info)) { }\n
                                                 if (MPI_File_open(MPI_COMM_SELF, "", 0, info, &fh)) { }\n
                                                 if (MPI_File_close(&fh)) { }\n'''):
      self.compilers.LIBS = oldLibs
      self.compilers.CPPFLAGS = oldFlags
      return
    self.addDefine('HAVE_MPIIO', 1)
    self.compilers.LIBS = oldLibs
    self.compilers.CPPFLAGS = oldFlags
    return

  def checkMPIDistro(self):
    '''Determine if MPICH_NUMVERSION, OMPI_MAJOR_VERSION or MSMPI_VER exist in mpi.h
       Used for consistency checking of MPI installation at compile time'''
    import re
    HASHLINESPACE = ' *(?:\n#.*\n *)*'
    oldFlags = self.compilers.CPPFLAGS
    self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)

    # the following packages are all derived originally from the MPICH implementation
    MPI_VER = ''
    # I_MPI_NUMVERSION is broken on Windows and only has a value of 0 so test also for the named version
    MPICHPKG = 'I_MPI'
    mpich_test = '#include <mpi.h>\nconst char *mpich_ver = '+MPICHPKG+'_VERSION;\n'
    if self.checkCompile(mpich_test):
      buf = self.outputPreprocess(mpich_test)
      try:
        mpich_numversion = re.compile('\nconst char *mpich_ver ='+HASHLINESPACE+r'"([\.0-9]+)"'+HASHLINESPACE+';').search(buf).group(1)
        self.addDefine('HAVE_'+MPICHPKG+'_VERSION',mpich_numversion)
        MPI_VER  = '  '+MPICHPKG+'_VERSION: '+mpich_numversion
      except:
        self.logPrint('Unable to parse '+MPICHPKG+' version from header. Probably a buggy preprocessor')
    for MPICHPKG in ['MPICH', 'I_MPI', 'MVAPICH2']:
      mpich_test = '#include <mpi.h>\nint mpich_ver = '+MPICHPKG+'_NUMVERSION;\n'
      if self.checkCompile(mpich_test):
        buf = self.outputPreprocess(mpich_test)
        try:
          mpich_numversion = re.compile('\nint mpich_ver ='+HASHLINESPACE+'([0-9]+)'+HASHLINESPACE+';').search(buf).group(1)
          MPI_VER += '  '+MPICHPKG+'_NUMVERSION: '+mpich_numversion
          self.addDefine('HAVE_'+MPICHPKG, 1)
          # for I_MPI and MVAPICH2, we can not use petscpkg_version.h since they are not a petsc package yet.
          # Anyway, we use PETSC_PKG_'MPICHPKG'_NUMVERSION to record the config time version for later compile time checking.
          self.addDefine('PKG_'+MPICHPKG+'_NUMVERSION',mpich_numversion)
          if MPICHPKG == 'MPICH':
            self.mpich_numversion = mpich_numversion
            MAJ = int(mpich_numversion)//10000000  # See comments in MPICH.py
            MIN = int(mpich_numversion)//100000%100
            REV = int(mpich_numversion)//1000%100
            self.mpich.version_tuple = (MAJ, MIN, REV) # version_tuple makes mpich included in petscpkg_version.h
          elif MPICHPKG == 'I_MPI': self.isIntelMPI = 1
        except:
          self.logPrint('Unable to parse '+MPICHPKG+' version from header. Probably a buggy preprocessor')
    if MPI_VER:
      self.compilers.CPPFLAGS = oldFlags
      self.mpi_pkg_version = MPI_VER+'\n'
      self.mpi_pkg = 'mpich'+mpich_numversion[0]
      return

    # NEC MPI is derived from MPICH but it does not keep MPICH related NUMVERSION
    necmpi_test = '#include <mpi.h>\nMPI_NEC_Function f = MPI_NEC_FUNCTION_NULL;\n'
    if self.checkCompile(necmpi_test):
      self.isNecMPI = 1
      self.addDefine('HAVE_NECMPI',1)

    # IBM Spectrum MPI is derived from Open MPI, we do not yet have specific tests for it
    # https://www.ibm.com/us-en/marketplace/spectrum-mpi
    openmpi_test = '#include <mpi.h>\nint ompi_major = OMPI_MAJOR_VERSION;\nint ompi_minor = OMPI_MINOR_VERSION;\nint ompi_release = OMPI_RELEASE_VERSION;\n'
    if self.checkCompile(openmpi_test):
      buf = self.outputPreprocess(openmpi_test)
      ompi_major_version = ompi_minor_version = ompi_release_version = 'unknown'
      try:
        ompi_major_version = re.compile('\nint ompi_major ='+HASHLINESPACE+'([0-9]+)'+HASHLINESPACE+';').search(buf).group(1)
        ompi_minor_version = re.compile('\nint ompi_minor ='+HASHLINESPACE+'([0-9]+)'+HASHLINESPACE+';').search(buf).group(1)
        ompi_release_version = re.compile('\nint ompi_release ='+HASHLINESPACE+'([0-9]+)'+HASHLINESPACE+';').search(buf).group(1)
        self.ompi_major_version = ompi_major_version
        self.ompi_version = tuple([int(i) for i in [ompi_major_version,ompi_minor_version,ompi_release_version]])
        self.openmpi.version_tuple = self.ompi_version # version_tuple makes openmpi included by petscpkg_version.h, so one can uses macros defined there
        self.addDefine('HAVE_OPENMPI', 1) # we have openmpi, though it is not necessarily installed by --download-openmpi
        self.mpi_pkg_version = '  OMPI_VERSION: '+ompi_major_version+'.'+ompi_minor_version+'.'+ompi_release_version+'\n'
        MPI_VER = '  OMPI_VERSION: '+ompi_major_version+'.'+ompi_minor_version+'.'+ompi_release_version
      except:
        self.logPrint('Unable to parse Open MPI version from header. Probably a buggy preprocessor')
    if MPI_VER:
      self.compilers.CPPFLAGS = oldFlags
      self.mpi_pkg_version = MPI_VER+'\n'
      self.mpi_pkg = 'openmpi'
      return

    msmpi_test = '#include <mpi.h>\n#define xstr(s) str(s)\n#define str(s) #s\n#if defined(MSMPI_VER)\nchar msmpi_hex[] = xstr(MSMPI_VER);\n#else\n#error not MSMPI\n#endif\n'
    if self.checkCompile(msmpi_test):
      buf = self.outputPreprocess(msmpi_test)
      msmpi_version = 'unknown'
      self.addDefine('HAVE_MSMPI',1) # flag we have MSMPI since we need to disable broken components
      try:
        msmpi_version = re.compile('\n'+r'char msmpi_hex\[\] = '+HASHLINESPACE+'\"([a-zA-Z0-9_]*)\"'+HASHLINESPACE+';').search(buf).group(1)
        MPI_VER = '  MSMPI_VERSION: '+msmpi_version
        self.addDefine('HAVE_MSMPI_VERSION',msmpi_version)
      except:
        self.logPrint('Unable to parse MSMPI version from header. Probably a buggy preprocessor')
    if MPI_VER:
      self.compilers.CPPFLAGS = oldFlags
      self.mpi_pkg_version = MPI_VER+'\n'
      return

    return

  def findMPIIncludeAndLib(self):
    '''Find MPI include paths and libraries from "mpicc -show" or Cray "cc --cray-print-opts=cflags/libs" and save.'''
    '''When the underlying C++ compiler used by CUDA or HIP is not the same'''
    '''as the MPICXX compiler (if any), the includes are needed for compiling with'''
    '''the CUDA or HIP compiler or the Kokkos compiler, and the libraries are needed'''
    '''when the Kokkos compiler wrapper is linking a Kokkos application.'''
    needed=False
    if hasattr(self.compilers, 'CUDAC') and self.cuda.found: needed = True
    if hasattr(self.compilers, 'HIPC') and self.hip.found: needed = True
    if hasattr(self.compilers, 'SYCLC') and self.sycl.found: needed = True
    if not needed: return

    if 'with-mpi-include' in self.argDB and 'with-mpi-lib' in self.argDB:
      self.includepaths = self.headers.toString(self.argDB['with-mpi-include'])
      self.mpilibs = self.libraries.toString(self.argDB['with-mpi-lib'])
      self.libpaths = ''
    else:
      import re
      cflagsOutput = ''
      libsOutput   = ''
      if config.setCompilers.Configure.isCrayPEWrapper(self.setCompilers.CC, self.log):
        # check these two env vars to only query MPICH headers and libs. Cray PE may include other libs.
        var1 = os.environ.get('PE_PKGCONFIG_LIBS').split(':') # the env var is in a format like 'mpich:libsci_mpi:libsci:dsmml'
        var2 = os.environ.get('PE_PKGCONFIG_PRODUCTS').split(':')
        env  = None # None means to inherit the current process' environment
        if ('mpich' in var1 and 'PE_MPICH' in var2): # assume the two env vars appear together if any one is set
          env = dict(os.environ, PE_PKGCONFIG_LIBS='mpich', PE_PKGCONFIG_PRODUCTS='PE_MPICH') # modify the two env vars only

        cflagsOutput = self.executeShellCommand([self.compilers.CC, '--cray-print-opts=cflags'], env=env, log = self.log)[0]
        # --no-as-needed since we always need MPI
        libsOutput   = self.executeShellCommand([self.compilers.CC, '--no-as-needed', '--cray-print-opts=libs'], env=env, log = self.log)[0]
      else:
        cflagsOutput = self.executeShellCommand(self.compilers.CC + ' -show', log = self.log)[0] # not list since CC might be 'mpicc -cc=clang'
        libsOutput   = cflagsOutput # same output as -show

      # find include paths
      self.includepaths = ''
      argIter = iter(cflagsOutput.split())
      try:
        while 1:
          arg = next(argIter)
          self.logPrint( 'Checking arg '+arg, 4, 'compilers')
          m = re.match(r'^-I.*$', arg)
          if m:
            self.logPrint('Found include option: '+arg, 4, 'compilers')
            self.includepaths += arg + ' '
            continue
      except StopIteration:
        pass
      # find libraries
      self.libpaths = ''
      self.mpilibs = ''
      argIter = iter(libsOutput.split())
      try:
        while 1:
          arg = next(argIter)
          self.logPrint( 'Checking arg '+arg, 4, 'compilers')
          m = re.match(r'^-L.*$', arg)
          if m:
            self.logPrint('Found -L link option: '+arg, 4, 'compilers')
            self.libpaths += arg + ' '
          m = re.match(r'^-Wl.*$', arg)
          if m:
            self.logPrint('Found -Wl link option: '+arg, 4, 'compilers')
            self.libpaths += arg + ' '
          m = re.match(r'^-l.*$', arg)
          if m:
            self.logPrint('Found -l link option: '+arg, 4, 'compilers')
            # TODO filter out system libraries
            self.mpilibs += arg + ' '
      except StopIteration:
        pass
    self.addMakeMacro('MPICXX_INCLUDES',self.includepaths)
    self.addMakeMacro('MPICXX_LIBS',self.libpaths + ' ' + self.mpilibs)
    return

  def log_print_mpi_h_line(self,buf):
    for line in buf.splitlines():
      if 'mpi.h' in line:
        self.log.write('mpi_h_line:\n'+line+'\n')
        return
    self.log.write('mpi.h not found in buf')
    return

  def PetscArchMPICheck(self):
    '''Check that previously configured for MPI include files are not in the PETSC_ARCH directory'''
    import os
    '''Makes sure incompatible mpi.h is not in the PETSC_ARCH/include directory'''
    build_mpi_h_dir = os.path.join(self.petscdir.dir,self.arch,'include')
    build_mpi_h = os.path.join(build_mpi_h_dir,'mpi.h')
    if os.path.isfile(build_mpi_h):
      self.log.write('mpi.h found in build dir! Checking if its a bad copy.\n')
      if self.usingMPIUni:
        raise RuntimeError('There is a copy of mpi.h in '+build_mpi_h_dir+' that will conflict with --with-mpi=0 build. do:\nrm -rf '+self.arch+' and run ./configure again\n')
      oldFlags = self.compilers.CPPFLAGS
      mpi_h_test = '#include <mpi.h>'
      # check self.include
      self.compilers.CPPFLAGS = oldFlags+' '+self.headers.toString(self.include)
      buf1 = self.outputPreprocess(mpi_h_test)
      self.log_print_mpi_h_line(buf1)
      # check build_mpi_h_dir and self.include
      self.compilers.CPPFLAGS = oldFlags+' '+self.headers.getIncludeArgument(build_mpi_h_dir)+' '+self.headers.toString(self.include)
      buf2 = self.outputPreprocess(mpi_h_test)
      self.log_print_mpi_h_line(buf2)
      if buf1 != buf2:
        raise RuntimeError('There is a copy of mpi.h in '+build_mpi_h_dir+' that is not compatible with your MPI, do:\nrm -rf '+self.arch+' and run ./configure again\n')
      self.compilers.CPPFLAGS = oldFlags
    return


  def configureLibrary(self):
    '''Calls the regular package configureLibrary and then does an additional test needed by MPI'''
    import platform
    if 'with-'+self.package+'-shared' in self.argDB:
      self.argDB['with-'+self.package] = 1
    config.package.Package.configureLibrary(self)
    if self.argDB['with-mpi-f90module-visibility']:
      self.addDefine('HAVE_MPI_F90MODULE_VISIBILITY',1)
    if self.setCompilers.usedMPICompilers:
      if 'with-mpi-include' in self.argDB: raise RuntimeError('Do not use --with-mpi-include when using MPI compiler wrappers')
      if 'with-mpi-lib' in self.argDB: raise RuntimeError('Do not use --with-mpi-lib when using MPI compiler wrappers')
    self.executeTest(self.checkMPIDistro)
    if any(x in platform.processor() for x in ['i386','x86','i86pc']) and config.setCompilers.Configure.isSolaris(self.log) and hasattr(self, 'mpich_numversion') and int(self.mpich_numversion) >= 30301300:
      # this is only needed if MPICH/HWLOC were compiled with optimization
      self.logWrite('Setting environmental variable to work around buggy HWLOC\nhttps://github.com/open-mpi/hwloc/issues/290\n')
      os.environ['HWLOC_COMPONENTS'] = '-x86'
      self.addDefine('HAVE_HWLOC_SOLARIS_BUG',1)
      self.logPrintWarning('This MPI implementation may have a bug in it that causes programs to hang. \
You may need to set the environmental variable HWLOC_COMPONENTS to -x86 to prevent such hangs')
    self.executeTest(self.configureMPI2) #depends on checkMPIDistro
    self.executeTest(self.configureMPI3) #depends on checkMPIDistro
    self.executeTest(self.configureMPI4)
    self.executeTest(self.configureMPIX)
    self.executeTest(self.configureMPIEXEC)
    self.executeTest(self.configureMPIEXEC_TAIL)
    self.executeTest(self.configureMPITypes)
    self.executeTest(self.SGIMPICheck)
    self.executeTest(self.CxxMPICheck)
    self.executeTest(self.FortranMPICheck)
    self.executeTest(self.configureIO) #depends on checkMPIDistro
    self.executeTest(self.findMPIIncludeAndLib)
    self.executeTest(self.PetscArchMPICheck)

    oldFlags = self.compilers.CPPFLAGS # Disgusting save and restore
    self.compilers.CPPFLAGS += ' '+self.headers.toString(self.include)
    for combiner in ['MPI_COMBINER_DUP', 'MPI_COMBINER_CONTIGUOUS', 'MPI_COMBINER_NAMED']:
      if self.checkCompile('#include <mpi.h>', 'int combiner = %s;(void)combiner' % (combiner,)):
        self.addDefine('HAVE_' + combiner,1)
    self.compilers.CPPFLAGS = oldFlags
