GRBs retractions - Param or value?

[Alasdair Allan]

Roy Williams wrote:
> Petr Kubanek wrote:
>> I'll try to generate schema for GCN, so we can then compare which  
>> approach is better - without solid examples, we will just put  
>> arguments with suit each side. Nobody at VOEvent seems to dig GCN  
>> packets description and put out UCDs which will be used to  
>> describe GRB - so I'll do that for schema.
>
> We have been converting GCN1 realtime into VOEvents for the last  
> few months. You can see them here: http://voeventnet.caltech.edu/ 
> GCN.shtml

Or an alternative translation, split by source, at;

     http://www.thinkingtelescopes.lanl.gov/Alerts.htm

> You will note grouping of the multiple events from a single  
> physical source.

Which is one of the things VOEvent has been designed to simplify with  
it's <CItation> tag after all...

> We would appreciate your help in refining our conversion code from  
> GCN1 to VOEvent.

One of the things that LANL has started to do after discussions  
between Robert and myself while I was out in New Mexico is adding the  
raw 160 byte packet into the <What> section as <Params>, e.g.

<Group name="GCN_RAW_DATA" >
    <Param value="63" name="INT_0" />
    <Param value="2" name="INT_1" />
    <Param value="0" name="INT_2" />
    <Param value="1757200" name="INT_3" />
    <Param value="222683" name="INT_4" />
    <Param value="13952" name="INT_5" />
    <Param value="1726916" name="INT_6" />
    <Param value="2209189" name="INT_7" />
    <Param value="125923" name="INT_8" />
    <Param value="0" name="INT_9" />
    <Param value="0" name="INT_10" />
    <Param value="0" name="INT_11" />
    <Param value="10468" name="INT_12" />
    <Param value="878" name="INT_13" />
    <Param value="-1100" name="INT_14" />
    <Param value="1024" name="INT_15" />
    <Param value="117856202" name="INT_16" />
    <Param value="448" name="INT_17" />
    <Param value="3" name="INT_18" />
    <Param value="16777216" name="INT_19" />
    <Param value="764" name="INT_20" />
    <Param value="1072" name="INT_21" />
    <Param value="808482675" name="INT_22" />
    <Param value="909259314" name="INT_23" />
    <Param value="808465208" name="INT_24" />
    <Param value="1651731760" name="INT_25" />
    <Param value="6515758" name="INT_26" />
    <Param value="0" name="INT_27" />
    <Param value="0" name="INT_28" />
    <Param value="0" name="INT_29" />
    <Param value="0" name="INT_30" />
    <Param value="0" name="INT_31" />
    <Param value="0" name="INT_32" />
    <Param value="0" name="INT_33" />
    <Param value="0" name="INT_34" />
    <Param value="0" name="INT_35" />
    <Param value="0" name="INT_36" />
    <Param value="0" name="INT_37" />
    <Param value="0" name="INT_38" />
    <Param value="10" name="INT_39" />
</Group>

The following Perl snippet will translate this back into the original  
GCN packet by parsing the full VOEvent message saved as a file, and  
spitting the 160 byte packet back out as another file.

#!/usr/bin/perl

die "$!" unless open( FILE, "<$ARGV[0]" );
while ( <FILE> ) {
    my $val = $1 if m/.*"(\D?\d+)".*"INT_\d+".*/;
    push @bytes, $val if defined $val;
}
close(FILE);

die "$!" unless open( FILE, ">$ARGV[0].out");
map { print FILE pack( "N", $_ ) } @bytes;
close(FILE);

Hopefully this will simplify the transition from 160 byte GCN binary  
packets to XML for a lot of sites.

Cheers,
Al.