====== EXERCISES ======
**[[RXNnetworkEX|Reaction Networks]]**, **[[NuclPhysInput|Nucl Physics Input]]**, **[[HydroEX|Hydro]]**, **[[BBNEX|BBN]]**

<box 80% left blue|**(During-Course Assignment)**>

  - Make sure everyone got the pre-test done and correct.
  - Re-run the pre-test, reducing the temperature in the thermodynamic file
    * Find the minimum temperatures at which silicon burning, oxygen burning and carbon burning occur.
  - Grab a new (larger, 150 species) sunet_sn150.txt from the document server.
    * Rename sunet_150.txt to sunet
    * Build a new Data directory from REACLIB
    * Create a new initial abundance file (matching the composition in the pretest)
    * Run same test problem with new network
    * Compare results to pre-test.
    * Compare timing of pre-test to new problem.

 
Additional possibilities:

**Run a reaction network with given nuclear input for:**

  -	Fixed temperature and density
    *	Try various temperatures and densities
    *	Try different network sizes
    *	Swap out a reaction rate with a different version
    *	Vary initial composition (X, Y, Z or Ye)
    *	Let evolve until Nuclear Statistical Equilibrium is reached
  -	Temperature/density trajectories

    *	$ T(t) = T(0)\exp{(-t/\tau)} $ or $\ T(t) = T(0)(1+\frac{t}{n\tau})^{-n} $

    *	$ [1.+f_{\nu}(T(0))]\rho (t) = \rho (0) [1.+f_{\nu}(T(t))](T(t)/T(0))^3$


    *	How do initial conditions affect the resulting nucleosynthesis
    *	How does the trajectory form affect the results?
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<box 80% left orange|**(Pre-Course Assignment)**>

**Download, compile and run the Reaction Network Code**

     - Download the [[rxnnetcode|Reaction Network Code]].
     - Compile the code with your fortran90 compiler, following the instructions in doc/Compiling.txt in the XNet distribution.
     - Report in the Reaction Network Code discussion thread your success with machine and compiler information.
     - Run a first test problem, following the instructions in doc/Running.txt in the XNet distribution. 
       * Your results should look like this figure. {{:XNet_test.png?direct&200}}
     - Try various temperatures and densities by changing the th_const file.
   
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~~DISCUSSION|Reaction Network Exercises Discussion~~