Re: isis-1.0.8 is available

On Fri, Apr 26, 2002 at 18:46 -0400, Craig Heinke wrote:
> Hello,
>    I am attempting to use the ISIS function "add_atable_model", and am having 
> difficulty altering the normalization of the additive table model with either 
> the renorm_counts command or fit_counts.  I am also using the pileup model; 
> here is what I've been doing:
> 
> import("xspec");
> set_kernel(1,"pileup"); 
> ()= load_data("X5_205bin_grp_noecl.pi");
> add_atable_model("NS_H_14.38.fits", "NS", ["T", "z","norm"]);
> fit_fun("phabs(1) * NS(1)");


Hi Craig,

This seems to be a problem with the interface to the xspec
additive table models -- through a silly oversight on 
my part, the norm parameter has no effect on the function
because it isn't explicitly in the table (duh).

In the meantime, I think you can include the normalization 
parameter via a simple S-Lang fit-function:

define coef_fit (l,h,p)
{
   return p[0];
}
add_slang_function ("coef", ["norm"]);

Then, use
   fit_fun ("phabs(1) * coef(1) * NS(1)");

Also, the table model should probably be loaded using
  add_atable_model("NS_H_14.38.fits", "NS", ["T", "z"]);
since the norm is presumably not one of the tabulated
parameters.

I will fix this problem in the next release so that
the normalization parameter is automatically included.

Thanks,

John

-- 
John C. Houck                       MIT Center for Space Research
NE80-6005: 617-253-3849                   77 Massachusetts Avenue
42:21:55.105N, 71:05:28.122W             Cambridge, MA 02139-4307
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