[daip] Re: cl2hf

[Leonia Kogan]

Hi,

I have carried out a test of CL2HF

First of all I can not find any UV data with DATUTC.NE.0
My brief look to the FITLD (which can be wrong) shows that DATUTC should 
be equal zero always.

So I created UVDATA using the my private version of the simulation task UVCON.
DATUTC=0.3 at the data.

CL2HF's subroutine DSCINF returns DATUTC=1.65 instead of 0.3 .

When I changed declaration of DATUTC to DOUBLE PRECISION as Dan Lebach 
recommends, CL2HF's subroutine DSCINF returns DATUTC=0.3000000119 close to 0.3.

So it looks like the DOUBLE PRECISION for DATUTC in CL2HF helps.

But I do not know why DATUTC should be DOUBLE PRECISION in CL2HF if
it is REAL in DANT.INC 

So I want to wait Eric to discuss the details.

Leonia
----- Begin Included Message -----

>From del at gyro.harvard.edu Wed Oct  3 16:48 MDT 2001
Date: Wed, 3 Oct 2001 18:48:02 -0400 (EDT)
From: del at cfa.harvard.edu
To: lkogan at zia.aoc.NRAO.EDU
Subject: Re: cl2hf
Cc: cwalker at zia.aoc.NRAO.EDU, daip at cv3.cv.nrao.edu, dgg at leo.gsfc.nasa.gov
Content-Type: text
Content-Length: 1546
X-Lines: 43
Status: RO


Hi Leonia,

Firstly, apologies for the delay.  It's been a VERY busy day here.

When I wrote:
> 
> >DATUTC is defined as REAL, while in fact it should be
> >defined as DOUBLE PRECISION.
> 

The statement is based on the the TYPE output from OGET.
Specifically, SN2HF (and, apparently, CL2HF) gets DATUTC from the
line:

      CALL OGET (ANTAB, 'KEY.DATUTC', TYPE, DIM, DATUTC, CDUMMY, IERR)

If you look at variable TYPE upon subroutine return, it contains
the value 1, which according to OGET documentation refers to a
double precision variable.  I can add that when DATUTC was defined
as real and the value of DATUTC was nonzero, the value of DATUTC
returned from the above subroutine call was garbage (something of
order 10^19), certainly not the value I read when looking at the
AN table via PRTAB.  When I redefined DATUTC as double precision,
the value returned from the subroutine call matched the value I
saw in the AN table.

Perhaps DATUTC is supposed to be REAL but some other location in
AIPS wrongfully defines it as DOUBLE PRECISION.

I maintain that, based on my (albeit limited) understanding, the
value of DATUTC stored in the AN table should be 0 regardless of whether
it is REAL or DOUBLE PRECISION.  DATUTC is not the same thing as
UT1UTC (which I state because in the last few experiments I've looked at,
DATUTC has been set equal to UT1UTC).

If you change AIPS so that DATUTC is defined as REAL throughout, please
let me know so that I can make the change in SN2HF.

Thanks for your prompt attention to this matter.

Dan



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