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EXERCISES

Big Bang Nucleosynthesis Exercises

(Pre-Course Assignment)

Download, compile and run the Big Bang Nucleosynthesis Code

  1. Compile the code with your fortran90 compiler.
  2. Report in the Reaction Network Code discussion thread your success with machine information.
  3. Generate light element abundance predictions for a range of initial baryon-to-photon ratios, $\eta$.
    • Create the “Schramm Plot”Schramm Plot:  Please note that these lines have a finite thickness.  This thickness denotes the uncertainties from nuclear reaction rates, propagated into the abundance predictions.
  4. Repeat with $N_\nu = 2$ and $4$.

Big Bang Nucleosynthesis Exercises Discussion

Hendrik Schatz, 2014/05/15 11:32

Successfully downloaded, compiled (gfortran public_bigbang.f90 -o public_bigbang.exe) and ran code. Takes maybe 5 minutes to complete on my mac so Schramm plot will take a while … probably need to modify code to run in a script via command line without keyboard input. Somebody wants to do that?

Justin Brown, 2014/05/19 04:21

Compiled and ran on Mac OS X 10.9.2 with gfortran 4.9.0. For those still trying to run a range of eta conveniently, the functionality is already built into the code. You just need to uncomment some of the lines in public_bigbang.f90 between 48 and 119.

Heiko Moeller, 2014/05/19 11:01

Compiled and ran successfully on Mint 16 and gfortran version 4.8.1. Takes rather long (~30min) on my laptop. However the ratio for Li7 and H is way too low in my calculation even if I run it for 1d12 seconds. Can anyone confirm this? I suspect that maybe the Be7 decay is not inclulded. Using the abundances of Be7+Li7, the ratio seems reasonable.

Matthew Gilmer, 2014/05/21 18:31

Heiko, my calculation also gave a way too low Lithium-7 to proton ratio, when compared with the Schramm plot above.

Raditya Utama, 2014/05/19 18:09

Compiled and ran on Mac OS X 10.8.5 and gfortran 4.8 It took ~7 mins on it

Julia Bliss, 2014/05/20 13:20

Compiled and ran on my Ubuntu 12.10 and gfortran 4.7

Matthew Gilmer, 2014/05/21 18:26

Compiled and ran on MAC OS 10.9.2 and gfortran 4.9.

MacKenzie Warren, 2014/05/22 13:19

Compiled and ran on Mac OSX 10.9 with gfortran 4.9

Richard Cyburt, 2014/05/23 08:01

For those having issues with how long this code takes, one can edit the file network.dek and change the parameter setting

    integer, parameter :: abignet = 500,

this is the maximum number of isotopes.

Reduce this number and see if you get any better performance.

Nicole Vassh, 2014/05/23 16:38

After using Richard's fix outlined above, compiled and ran using MinGW with gfortran 4.8.1. Took about 9 min to run with N_nu = 2.

Donald Willcox, 2014/05/26 10:43

Compiled and ran just fine on Fedora 20 kernel 3.14.4 with gfortran 4.8.2. (Also tried compiling on a machine with gfortran 4.4 and received lots of compile errors that were fixed using 4.8.2.)

Tsung-Han Yeh, 2014/05/26 10:46

Linux version 3.7.10-1.28-default, gcc version 4.7.2, ifort Version 11.0. Got very low 7Li abundance.

Alexander Dombos, 2014/05/27 19:20

Compiled on my Mac OS X 10.7.5 using gfortran 4.8.2. Following the advice from a participant above, I commented out some of the lines in public_bigbang.f90 between 48 and 119. The code has been running a very long time, and I'm not sure if changing the parameter abignet as suggested above will help. Therefore, I haven't been able to reproduce the Schramm plot.

Sarah Schwartz, 2014/05/27 21:37

Compiled and ran on Linux 3.2.0 with gfortran.

Fei Yuan, 2014/05/27 21:49

Compiled successfully on Debian 3.2 with gfortran 4.7.

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bbnex.1400075290.txt.gz · Last modified: 2014/05/14 09:48 by cyburt