June 2015 - petsc-dev - mailman3.cels.anl.gov

MatCreateVecs interface
by Stefano Zampini 25 Jun '15

25 Jun '15

Why the current interface in MatCreateVecs requires that a matrix has been already either allocated or setup ? Shouldn’t be enough to check if the layout has been already setup? Stefano

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Let Us Help With Your Bioinformatics Projects
by Justin Li, Ph.D., Lead Bioinformatician, AccuraScience 24 Jun '15

24 Jun '15

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Re: [petsc-dev] Fortran Interfaces and interrupting SNESSolve
by Jed Brown 24 Jun '15

24 Jun '15

Matthew Knepley <knepley(a)gmail.com> writes: > I don't know how to do this one since we overhauled our Fortran callbacks. > Jed or Satish? Emulate snessetngs_ (for 'maint') and fix SNESSetUpdate to take a context (for 'master').

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Re: [petsc-dev] Fortran Interfaces and interrupting SNESSolve
by Barry Smith 24 Jun '15

24 Jun '15

> On Jun 24, 2015, at 10:03 AM, Matthew Knepley <knepley(a)gmail.com> wrote: > > On Wed, Jun 24, 2015 at 9:48 AM, John O'Sullivan <jp.osullivan(a)auckland.ac.nz> wrote: > Hi Matt, > > I's just wondering if you'd had a chance to do the Fortran interface for SNESSetUpdate? > > I don't know how to do this one since we overhauled our Fortran callbacks. Jed or Satish? > > Also what would you guys recommend for interrupting SNESSolve? For example when the solution vector is outside the range for the RHS function that can be evaluated. I assume you mean the "current solution" vector is outside of the domain of the RHS? > > I think the new scheme is to return a NaN. Is that right Barry? Yes, just put a Inf into the function vector (at any location). Then then SNES will end with a SNES_DIVERGED_FNORM_NAN. Barry > > Matt > > Cheers > John > > -- > Dr John O'Sullivan > Lecturer > Department of Engineering Science > University of Auckland, New Zealand > email: > jp.osullivan at auckland.ac.nz > > tel: +64 (0)9 923 85353 > > From: petsc-dev-bounces(a)mcs.anl.gov [petsc-dev-bounces(a)mcs.anl.gov] on behalf of Matthew Knepley [knepley(a)gmail.com] > Sent: Wednesday, 24 June 2015 10:30 p.m. > To: Marco Zocca > Cc: PETSc > Subject: Re: [petsc-dev] "pure" subset of operators > > On Wed, Jun 24, 2015 at 2:48 AM, Marco Zocca <zocca.marco(a)gmail.com> wrote: > Hello, > is there an index of the PETSc operations (e.g. mathematical on Vec's > and Mat's) that do NOT overwrite the operands? > I understand in-place operations are more efficient, but they make it > harder to reason about the program's operation. > > We do not make a separate list of these. > > Thanks, > > Matt > > Thank you in advance > > > > -- > What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. > -- Norbert Wiener > > > > -- > What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. > -- Norbert Wiener

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Re: [petsc-dev] Fortran Interfaces and interrupting SNESSolve
by Matthew Knepley 24 Jun '15

24 Jun '15

On Wed, Jun 24, 2015 at 9:48 AM, John O'Sullivan < jp.osullivan(a)auckland.ac.nz> wrote: > Hi Matt, > > I's just wondering if you'd had a chance to do the Fortran interface for > SNESSetUpdate? > I don't know how to do this one since we overhauled our Fortran callbacks. Jed or Satish? > Also what would you guys recommend for interrupting SNESSolve? For example > when the solution vector is outside the range for the RHS function that can > be evaluated. > I think the new scheme is to return a NaN. Is that right Barry? Matt > Cheers > John > > -- > Dr John O'Sullivan > Lecturer > Department of Engineering Science > University of Auckland, New Zealand > email: jp.osullivan at auckland.ac.nz <https://lists.mcs.anl.gov/mailman/listinfo/petsc-dev> > tel: +64 (0)9 923 85353 > > ------------------------------ > *From:* petsc-dev-bounces(a)mcs.anl.gov [petsc-dev-bounces(a)mcs.anl.gov] on > behalf of Matthew Knepley [knepley(a)gmail.com] > *Sent:* Wednesday, 24 June 2015 10:30 p.m. > *To:* Marco Zocca > *Cc:* PETSc > *Subject:* Re: [petsc-dev] "pure" subset of operators > > On Wed, Jun 24, 2015 at 2:48 AM, Marco Zocca <zocca.marco(a)gmail.com> > wrote: > >> Hello, >> is there an index of the PETSc operations (e.g. mathematical on Vec's >> and Mat's) that do NOT overwrite the operands? >> I understand in-place operations are more efficient, but they make it >> harder to reason about the program's operation. >> > > We do not make a separate list of these. > > Thanks, > > Matt > > >> Thank you in advance >> > > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener

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Fortran Interfaces and interrupting SNESSolve
by John O'Sullivan 24 Jun '15

24 Jun '15

Hi Matt, I's just wondering if you'd had a chance to do the Fortran interface for SNESSetUpdate? Also what would you guys recommend for interrupting SNESSolve? For example when the solution vector is outside the range for the RHS function that can be evaluated. Cheers John -- Dr John O'Sullivan Lecturer Department of Engineering Science University of Auckland, New Zealand email: jp.osullivan at auckland.ac.nz<https://lists.mcs.anl.gov/mailman/listinfo/petsc-dev> tel: +64 (0)9 923 85353 ________________________________ From: petsc-dev-bounces(a)mcs.anl.gov [petsc-dev-bounces(a)mcs.anl.gov] on behalf of Matthew Knepley [knepley(a)gmail.com] Sent: Wednesday, 24 June 2015 10:30 p.m. To: Marco Zocca Cc: PETSc Subject: Re: [petsc-dev] "pure" subset of operators On Wed, Jun 24, 2015 at 2:48 AM, Marco Zocca <zocca.marco(a)gmail.com<mailto:[email protected]>> wrote: Hello, is there an index of the PETSc operations (e.g. mathematical on Vec's and Mat's) that do NOT overwrite the operands? I understand in-place operations are more efficient, but they make it harder to reason about the program's operation. We do not make a separate list of these. Thanks, Matt Thank you in advance -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener

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Re: [petsc-dev] "pure" subset of operators
by Matthew Knepley 24 Jun '15

24 Jun '15

On Wed, Jun 24, 2015 at 2:48 AM, Marco Zocca <zocca.marco(a)gmail.com> wrote: > Hello, > is there an index of the PETSc operations (e.g. mathematical on Vec's > and Mat's) that do NOT overwrite the operands? > I understand in-place operations are more efficient, but they make it > harder to reason about the program's operation. > We do not make a separate list of these. Thanks, Matt > Thank you in advance > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener

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"pure" subset of operators
by Marco Zocca 24 Jun '15

24 Jun '15

Hello, is there an index of the PETSc operations (e.g. mathematical on Vec's and Mat's) that do NOT overwrite the operands? I understand in-place operations are more efficient, but they make it harder to reason about the program's operation. Thank you in advance

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Re: [petsc-dev] hdf5 viewer question
by Dominic Meiser 23 Jun '15

23 Jun '15

Hi Matt, Thanks for your suggestion. I rebuilt with --with-64-bit-indices=1 but I get the same result. Any other ideas? Cheers, Dominic On 06/23/2015 09:23 AM, Matthew Knepley wrote: > On Tue, Jun 23, 2015 at 9:38 AM, Dominic Meiser <dmeiser(a)txcorp.com > <mailto:[email protected]>> wrote: > > Hi, > > I'm running into an issue with the Hdf5 viewer. For parallel vectors > of length larger than 2^16 I get the error message below. The vector > is created from a 1D DMDA with 2 dofs. Serial vectors work fine as > do vectors of length <= 2^16. The error message is reproduced below. > The issue can be reproduced with the attached example with 'mpirun > -np 2 ./testcase -da_grid_x 65537'. > > Do I need to configure the viewer in some way before using it? > > > You may have to configure with --with-64-bit-indices > > Thanks, > > Matt > > Thanks, > Dominic > > > > HDF5-DIAG: Error detected in HDF5 (1.8.12) MPI-process 0: > #000: H5D.c line 170 in H5Dcreate2(): unable to create dataset > major: Dataset > minor: Unable to initialize object > #001: H5Dint.c line 439 in H5D__create_named(): unable to create > and link to dataset > major: Dataset > minor: Unable to initialize object > #002: H5L.c line 1638 in H5L_link_object(): unable to create new > link to object > major: Links > minor: Unable to initialize object > #003: H5L.c line 1882 in H5L_create_real(): can't insert link > major: Symbol table > minor: Unable to insert object > #004: H5Gtraverse.c line 861 in H5G_traverse(): internal path > traversal failed > major: Symbol table > minor: Object not found > #005: H5Gtraverse.c line 641 in H5G_traverse_real(): traversal > operator failed > major: Symbol table > minor: Callback failed > #006: H5L.c line 1685 in H5L_link_cb(): unable to create object > major: Object header > minor: Unable to initialize object > #007: H5O.c line 3015 in H5O_obj_create(): unable to open object > major: Object header > HDF5-DIAG: Error detected in HDF5 (1.8.12) MPI-process 1: > #000: H5D.c line 170 in H5Dcreate2(): unable to create dataset > major: Dataset > minor: Unable to initialize object > #001: H5Dint.c line 439 in H5D__create_named(): unable to create > and link to dataset > major: Dataset > minor: Unable to initialize object > #002: H5L.c line 1638 in H5L_link_object(): unable to create new > link to object > major: Links > minor: Unable to initialize object > #003: H5L.c line 1882 in H5L_create_real(): can't insert link > major: Symbol table > minor: Unable to insert object > #004: H5Gtraverse.c line 861 in H5G_traverse(): internal path > traversal failed > major: Symbol table > minor: Object not found > #005: H5Gtraverse.c line 641 in H5G_traverse_real(): traversal > operator failed > major: Symbol table > minor: Callback failed > #006: H5L.c line 1685 in H5L_link_cb(): unable to create object > major: Object header > minor: Unable to initialize object > #007: H5O.c line 3015 in H5O_obj_create(): unable to open object > major: Object header > minor: Can't open object > #008: H5Doh.c line 293 in H5O__dset_create(): unable to create > dataset > major: Dataset > minor: Unable to initialize object > #009: H5Dint.c line 1044 in H5D__create(): unable to construct > layout information > major: Dataset > minor: Unable to initialize object > #010: H5Dchunk.c line 539 in H5D__chunk_construct(): chunk size > must be <= maximum dimension size for fixed-sized dimensions > major: Dataset > minor: Unable to initialize object > minor: Can't open object > #008: H5Doh.c line 293 in H5O__dset_create(): unable to create > dataset > major: Dataset > minor: Unable to initialize object > #009: H5Dint.c line 1044 in H5D__create(): unable to construct > layout information > major: Dataset > minor: Unable to initialize object > #010: H5Dchunk.c line 539 in H5D__chunk_construct(): chunk size > must be <= maximum dimension size for fixed-sized dimensions > major: Dataset > minor: Unable to initialize object > [0]PETSC ERROR: [1]PETSC ERROR: --------------------- Error Message > -------------------------------------------------------------- > --------------------- Error Message > -------------------------------------------------------------- > [0]PETSC ERROR: [1]PETSC ERROR: Error in external library > Error in external library > [0]PETSC ERROR: Error in HDF5 call H5Dcreate2() Status -1 > [0]PETSC ERROR: [1]PETSC ERROR: Error in HDF5 call H5Dcreate2() > Status -1 > [1]PETSC ERROR: See > http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble > shooting. > See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble > shooting. > [0]PETSC ERROR: Petsc Release Version 3.6.0, unknown > [0]PETSC ERROR: [1]PETSC ERROR: Petsc Release Version 3.6.0, unknown > [1]PETSC ERROR: ./testcase on a fftw_test named longspeak.txcorp.com > <http://longspeak.txcorp.com> by dmeiser Mon Jun 22 16:59:21 2015 > ./testcase on a fftw_test named longspeak.txcorp.com > <http://longspeak.txcorp.com> by dmeiser Mon Jun 22 16:59:21 2015 > [0]PETSC ERROR: Configure options --download-hdf5=1 > --download-fftw=1 --with-mpi=1 PETSC_ARCH=fftw_test > [0]PETSC ERROR: [1]PETSC ERROR: Configure options --download-hdf5=1 > --download-fftw=1 --with-mpi=1 PETSC_ARCH=fftw_test > [1]PETSC ERROR: #1 VecView_MPI_HDF5_DA() line 535 in > /home/scratch/petsc/src/dm/impls/da/gr2.c > #1 VecView_MPI_HDF5_DA() line 535 in > /home/scratch/petsc/src/dm/impls/da/gr2.c > [0]PETSC ERROR: #2 VecView_MPI_DA() line 713 in > /home/scratch/petsc/src/dm/impls/da/gr2.c > [1]PETSC ERROR: #2 VecView_MPI_DA() line 713 in > /home/scratch/petsc/src/dm/impls/da/gr2.c > [0]PETSC ERROR: #3 VecView() line 618 in > /home/scratch/petsc/src/vec/vec/interface/vector.c > [1]PETSC ERROR: #3 VecView() line 618 in > /home/scratch/petsc/src/vec/vec/interface/vector.c > [0]PETSC ERROR: [1]PETSC ERROR: #4 dump() line 75 in testcase.c > #4 dump() line 75 in testcase.c > [0]PETSC ERROR: #5 main() line 31 in testcase.c > [1]PETSC ERROR: #5 main() line 31 in testcase.c > [0]PETSC ERROR: [1]PETSC ERROR: PETSc Option Table entries: > [1]PETSC ERROR: PETSc Option Table entries: > [0]PETSC ERROR: -da_grid_x 65537 > [0]PETSC ERROR: -da_grid_x 65537 > [1]PETSC ERROR: ----------------End of Error Message -------send > entire error message to petsc-maint(a)mcs.anl.gov---------- > ----------------End of Error Message -------send entire error > message to petsc-maint(a)mcs.anl.gov---------- > [cli_0]: aborting job: > application called MPI_Abort(MPI_COMM_WORLD, 76) - process 0 > [cli_1]: aborting job: > application called MPI_Abort(MPI_COMM_WORLD, 76) - process 1 > > =================================================================================== > = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES > = PID 15847 RUNNING AT longspeak.txcorp.com > <http://longspeak.txcorp.com> > = EXIT CODE: 76 > = CLEANING UP REMAINING PROCESSES > = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES > =================================================================================== > > -- > Dominic Meiser > Tech-X Corporation > 5621 Arapahoe Avenue > Boulder, CO 80303 > USA > Telephone: 303-996-2036 <tel:303-996-2036> > Fax: 303-448-7756 <tel:303-448-7756> > www.txcorp.com <http://www.txcorp.com> > > > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which > their experiments lead. > -- Norbert Wiener -- Dominic Meiser Tech-X Corporation 5621 Arapahoe Avenue Boulder, CO 80303 USA Telephone: 303-996-2036 Fax: 303-448-7756 www.txcorp.com

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Re: [petsc-dev] hdf5 viewer question
by Matthew Knepley 23 Jun '15

23 Jun '15

On Tue, Jun 23, 2015 at 12:39 PM, Dominic Meiser <dmeiser(a)txcorp.com> wrote: > Hi Matt, > > Thanks for your suggestion. I rebuilt with --with-64-bit-indices=1 but I > get the same result. Any other ideas? > There could be a bug with the calculation of chunksize. I will run your example as soon as I can. Thanks, Matt > Cheers, > Dominic > > On 06/23/2015 09:23 AM, Matthew Knepley wrote: > >> On Tue, Jun 23, 2015 at 9:38 AM, Dominic Meiser <dmeiser(a)txcorp.com >> <mailto:[email protected]>> wrote: >> >> Hi, >> >> I'm running into an issue with the Hdf5 viewer. For parallel vectors >> of length larger than 2^16 I get the error message below. The vector >> is created from a 1D DMDA with 2 dofs. Serial vectors work fine as >> do vectors of length <= 2^16. The error message is reproduced below. >> The issue can be reproduced with the attached example with 'mpirun >> -np 2 ./testcase -da_grid_x 65537'. >> >> Do I need to configure the viewer in some way before using it? >> >> >> You may have to configure with --with-64-bit-indices >> >> Thanks, >> >> Matt >> >> Thanks, >> Dominic >> >> >> >> HDF5-DIAG: Error detected in HDF5 (1.8.12) MPI-process 0: >> #000: H5D.c line 170 in H5Dcreate2(): unable to create dataset >> major: Dataset >> minor: Unable to initialize object >> #001: H5Dint.c line 439 in H5D__create_named(): unable to create >> and link to dataset >> major: Dataset >> minor: Unable to initialize object >> #002: H5L.c line 1638 in H5L_link_object(): unable to create new >> link to object >> major: Links >> minor: Unable to initialize object >> #003: H5L.c line 1882 in H5L_create_real(): can't insert link >> major: Symbol table >> minor: Unable to insert object >> #004: H5Gtraverse.c line 861 in H5G_traverse(): internal path >> traversal failed >> major: Symbol table >> minor: Object not found >> #005: H5Gtraverse.c line 641 in H5G_traverse_real(): traversal >> operator failed >> major: Symbol table >> minor: Callback failed >> #006: H5L.c line 1685 in H5L_link_cb(): unable to create object >> major: Object header >> minor: Unable to initialize object >> #007: H5O.c line 3015 in H5O_obj_create(): unable to open object >> major: Object header >> HDF5-DIAG: Error detected in HDF5 (1.8.12) MPI-process 1: >> #000: H5D.c line 170 in H5Dcreate2(): unable to create dataset >> major: Dataset >> minor: Unable to initialize object >> #001: H5Dint.c line 439 in H5D__create_named(): unable to create >> and link to dataset >> major: Dataset >> minor: Unable to initialize object >> #002: H5L.c line 1638 in H5L_link_object(): unable to create new >> link to object >> major: Links >> minor: Unable to initialize object >> #003: H5L.c line 1882 in H5L_create_real(): can't insert link >> major: Symbol table >> minor: Unable to insert object >> #004: H5Gtraverse.c line 861 in H5G_traverse(): internal path >> traversal failed >> major: Symbol table >> minor: Object not found >> #005: H5Gtraverse.c line 641 in H5G_traverse_real(): traversal >> operator failed >> major: Symbol table >> minor: Callback failed >> #006: H5L.c line 1685 in H5L_link_cb(): unable to create object >> major: Object header >> minor: Unable to initialize object >> #007: H5O.c line 3015 in H5O_obj_create(): unable to open object >> major: Object header >> minor: Can't open object >> #008: H5Doh.c line 293 in H5O__dset_create(): unable to create >> dataset >> major: Dataset >> minor: Unable to initialize object >> #009: H5Dint.c line 1044 in H5D__create(): unable to construct >> layout information >> major: Dataset >> minor: Unable to initialize object >> #010: H5Dchunk.c line 539 in H5D__chunk_construct(): chunk size >> must be <= maximum dimension size for fixed-sized dimensions >> major: Dataset >> minor: Unable to initialize object >> minor: Can't open object >> #008: H5Doh.c line 293 in H5O__dset_create(): unable to create >> dataset >> major: Dataset >> minor: Unable to initialize object >> #009: H5Dint.c line 1044 in H5D__create(): unable to construct >> layout information >> major: Dataset >> minor: Unable to initialize object >> #010: H5Dchunk.c line 539 in H5D__chunk_construct(): chunk size >> must be <= maximum dimension size for fixed-sized dimensions >> major: Dataset >> minor: Unable to initialize object >> [0]PETSC ERROR: [1]PETSC ERROR: --------------------- Error Message >> -------------------------------------------------------------- >> --------------------- Error Message >> -------------------------------------------------------------- >> [0]PETSC ERROR: [1]PETSC ERROR: Error in external library >> Error in external library >> [0]PETSC ERROR: Error in HDF5 call H5Dcreate2() Status -1 >> [0]PETSC ERROR: [1]PETSC ERROR: Error in HDF5 call H5Dcreate2() >> Status -1 >> [1]PETSC ERROR: See >> http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble >> shooting. >> See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble >> shooting. >> [0]PETSC ERROR: Petsc Release Version 3.6.0, unknown >> [0]PETSC ERROR: [1]PETSC ERROR: Petsc Release Version 3.6.0, unknown >> [1]PETSC ERROR: ./testcase on a fftw_test named longspeak.txcorp.com >> <http://longspeak.txcorp.com> by dmeiser Mon Jun 22 16:59:21 2015 >> ./testcase on a fftw_test named longspeak.txcorp.com >> <http://longspeak.txcorp.com> by dmeiser Mon Jun 22 16:59:21 2015 >> [0]PETSC ERROR: Configure options --download-hdf5=1 >> --download-fftw=1 --with-mpi=1 PETSC_ARCH=fftw_test >> [0]PETSC ERROR: [1]PETSC ERROR: Configure options --download-hdf5=1 >> --download-fftw=1 --with-mpi=1 PETSC_ARCH=fftw_test >> [1]PETSC ERROR: #1 VecView_MPI_HDF5_DA() line 535 in >> /home/scratch/petsc/src/dm/impls/da/gr2.c >> #1 VecView_MPI_HDF5_DA() line 535 in >> /home/scratch/petsc/src/dm/impls/da/gr2.c >> [0]PETSC ERROR: #2 VecView_MPI_DA() line 713 in >> /home/scratch/petsc/src/dm/impls/da/gr2.c >> [1]PETSC ERROR: #2 VecView_MPI_DA() line 713 in >> /home/scratch/petsc/src/dm/impls/da/gr2.c >> [0]PETSC ERROR: #3 VecView() line 618 in >> /home/scratch/petsc/src/vec/vec/interface/vector.c >> [1]PETSC ERROR: #3 VecView() line 618 in >> /home/scratch/petsc/src/vec/vec/interface/vector.c >> [0]PETSC ERROR: [1]PETSC ERROR: #4 dump() line 75 in testcase.c >> #4 dump() line 75 in testcase.c >> [0]PETSC ERROR: #5 main() line 31 in testcase.c >> [1]PETSC ERROR: #5 main() line 31 in testcase.c >> [0]PETSC ERROR: [1]PETSC ERROR: PETSc Option Table entries: >> [1]PETSC ERROR: PETSc Option Table entries: >> [0]PETSC ERROR: -da_grid_x 65537 >> [0]PETSC ERROR: -da_grid_x 65537 >> [1]PETSC ERROR: ----------------End of Error Message -------send >> entire error message to petsc-maint(a)mcs.anl.gov---------- >> ----------------End of Error Message -------send entire error >> message to petsc-maint(a)mcs.anl.gov---------- >> [cli_0]: aborting job: >> application called MPI_Abort(MPI_COMM_WORLD, 76) - process 0 >> [cli_1]: aborting job: >> application called MPI_Abort(MPI_COMM_WORLD, 76) - process 1 >> >> >> =================================================================================== >> = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES >> = PID 15847 RUNNING AT longspeak.txcorp.com >> <http://longspeak.txcorp.com> >> = EXIT CODE: 76 >> = CLEANING UP REMAINING PROCESSES >> = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES >> >> =================================================================================== >> >> -- >> Dominic Meiser >> Tech-X Corporation >> 5621 Arapahoe Avenue >> Boulder, CO 80303 >> USA >> Telephone: 303-996-2036 <tel:303-996-2036> >> Fax: 303-448-7756 <tel:303-448-7756> >> www.txcorp.com <http://www.txcorp.com> >> >> >> >> >> -- >> What most experimenters take for granted before they begin their >> experiments is infinitely more interesting than any results to which >> their experiments lead. >> -- Norbert Wiener >> > > -- > Dominic Meiser > Tech-X Corporation > 5621 Arapahoe Avenue > Boulder, CO 80303 > USA > Telephone: 303-996-2036 > Fax: 303-448-7756 > www.txcorp.com > -- What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead. -- Norbert Wiener

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