[Halld-offline] problem with spread of values for particle gun

[David Lawrence]

Hi Richard,

     I thought the call to FFSET('SIZE', 16) that Sascha put in made the 
max size 16 characters opening up the naming space from the 4 character 
limit a bit. Can anyone else confirm this?

Regards,
-Dave

On 3/21/11 3:18 PM, Richard Jones wrote:
> Kei,
>
> Another one of those follies from FFREAD that I recently re-learned is 
> that it matters how many letters you put in the leading word in the 
> lines of control.in.  If the full command name is more than 4 
> characters then any string of 4 or more characters that coincides with 
> the name works.  For example, any of the following cards will work for 
> the INFILE command:
>
>     * INFI   'rhop.hddm' <--<< ok
>     * INFIL 'rhop.hddm' <--<< ok
>     * INFILE 'rhop.hddm' <--<< ok
>
>
> HOWEVER, if the specification is a shortened form, then spelling out 
> the complete word fails.  For example, the command for debug output is 
> spelled DEBU (without the G).   The first one below works, while the 
> second one is silently ignored.
>
>     * DEBU   1 10 1000 <--<< ok
>     * DEBUG 1 10 1000 <--<< bad form
>
> Just thought you might like to know.
>
> -Richard J.
>
>
>
> On 3/21/2011 2:43 PM, Kei Moriya wrote:
>> Dear offliners,
>>
>> I wanted to let you know that there is a little bug
>> when generating particles with a spread in
>> momentum and angle with the particle gun.
>>
>> When generating events with the particle gun,
>> I specify the central value of p, theta, and phi,
>> along with the full width of each value.
>> What I have noticed is that if I specify for
>> example
>> c   particle  momentum  theta  phi  delta_momentum delta_theta delta_phi
>> KINE   114      5.0       30.   0.      0.5              30        360.
>>
>> which means generate protons(offset=100+PID=14) with
>> p = 5.0 +/- 5
>> theta = 30 +/- 15
>> phi = 0 +/- 180.
>>
>> What I have noticed is that the decimal point for
>> the momentum values are essential, since without
>> the decimal point, the spread becomes 0!
>> I assume this is a simple bug of taking the value
>> as an int instead of a float.
>>
>> The plot attachd show the difference when
>> a "." is added to delta_momentum so that the
>> top plot (with decimal point) has a full width
>> of 5 (2.5<p<7.5), while the bottom (without decimal
>> point) has no width.
>>
>> I assume the place to correct this is within
>> gukine.F in sim-recon/sim-recon/src/programs/Simulations/HDGeant/
>> but I'll let the experts fix this so I don't
>> break anything.
>>
>> One thing that comes as a consequence of this is that
>> the plots I showed last week had theta exactly
>> at 0.25,0.75,1.25, ... degrees, and NO spread.
>> I'm not sure how many other people are using the
>> particle gun, but you may want to check that you
>> are actually getting a spread in your values.
>>
>> 	Kei
>>
>
>
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