View source for Information about the new FineMesh B-field option

A new "fine-mesh" option for the magnetic field map is now available.  The code interpolates over the coarse field map in CalibDB in fine bins, currently set to 1 mm steps in both z and r.  The option is available in a jana program 
by setting the '''-DBFIELD_TYPE=FineMesh''' parameter.  If EVIO is not available, the code generates the fine-mesh map 
in memory at the start of a run.  If EVIO is available, the fine-mesh B-field data is written to the current working 
directory and is read in at the beginning of execution the next time the executable is called.

Benchmark results (in Hz) on ifarml6 with 4 threads analyzing single particle events (0.1-3.1 GeV/c) with no background:

<pre>
          Kalman Filter    Least-squares (ALT1)
          protons pions    protons pions
-----------------------------------------------
FineMesh    65.1  58.2       51.0  59.9
Standard    48.5  45.6       47.2  62.8
</pre>