Configuration file description

The table below describes the content of a configuration file used as input and output file in the APO software. An example of configuration file is also given for multiconfiguration observations.

NOTE:

The lengths have no particular units but it should be homogenous: the same units should be taken for all the lengths.
The obsolete parameters should still be given (as long as the source is not updated). Any value is OK.
Using a configfile as input allows to give a lot of parameters at once but does not necessarily take advantage of all the potentiality of the APO software. It might be necessary in some particular cases (e.g. when optimizing a single configuration for several source declinations) to specify additionnal parameters within a C++ program using the APO library. It is always very useful to use a configfile as output especially when IDL routines are used to view the results.

LISTING	LINE NUMBER	DESCRIPTION
! Thu Jan 25 13:34:04 2001	1	Date of creation
64 / nb of ant	2	Number of antennas.
1 / nb of conf	3	Number of configurations. Note that this is the number of configurations to be considered when observing the same source and merging the uv-samples of all the configurations, i.e. for multiconfiguration observations. The pads positions will be optimized in order to make the different configurations complementary in terms of distribution of samples.
0 / nb of common ant	4	Number of pads shared between the configurations.
4032 / nb of visibilities	5	Total number of samples.
-23.0 / site latitude	6	Latitude in degrees of the site where the array is positionned.
0.20 / opacity	7	Opacity of the atmosphere (used to compute the weights of the data).
-53.0 / source declination	8	Declination of the source in degrees the array is optimized for.
0.0 / initial hour angle	9	Hour angle at the begining of the observation. One value for each configuration .
0.10 / integration time	10	Observation duration. One value for each configuration should be given.
0.10 / hour angle sample interval	11	Averaging time of a measurement. One value for each configuration.
200.0 / maximal baseline	12	Largest projected baseline allowed. One value for each configuration.
1.0 / tolerance	13	OBSOLETE
200.0 / max baseline for model	14	External boundary for the circular grid to be used.
12.0 / diameter	15	Antenna diameter.
15.0 / minimum distance between antennas	16	Smallest distance allowed between the antennas.
12.0 / minimum baseline	17	Shortest projected baseline length allowed. Note that this is different from the last parameter as it is projected on the sky.
12.0 / min baseline for model	18	Inner boundary for the grid.
0.0 / mask radius	19	OBSOLETE
0.0 / minimum distance from map center	20	OBSOLETE
100.0 / maximum authorized displacement	21	OBSOLETE
mask_5deg_350.fits / name of map file	22	Name of the fits file containing the binary mask of the topographic constaints. Note that the mask should have 1's where antennas are forbidden. (Can be anyting if the last parameter is equal to 0.)
10.00 / x pixel size of map	23	Size of the pixel of the mask along x axis and in the same unit as the diameter. (Can be anyting if the last parameter is equal to 0.)
10.00 / y pixel size of map	24	Size of the pixel of the mask along y axis and in the same unit as the diameter. (Can be anyting if the last parameter is equal to 0.)
1850.0 / x center of map	25	X coordinate of the point to be taken as origin for all the antenna positions. This is the distance of this point to the left border of the mask in length unit. (Can be anything if the last parameter is equal to 0.)
1750.0 / y center of map	26	Y coordinate of the point to be taken as origin for all the antenna positions. This is the distance of this point to the bottom border of the mask in length unit. (Can be anything if the last parameter is equal to 0.)
200.0 / fwhm of model	27	FWHM in length unit of the Gaussian distribution of samples the array should be optimized for.
1 / map as background	28	1 if a mask should be considered for the topographic constraints. 0 otherwise.
-0.735 12.232 0 -4.216 30.256 0 -3.896 -29.697 0 12.205 -0.867 0 -11.905 -8.257 0 -20.512 8.931 0 25.108 15.795 0 -26.979 39.580 0 24.834 -31.405 0 etc...	29....	List of antenna positions. In each line the first 2 parameters are respectively x and y in length units. The third parameter says if the antenna can be moved (0)or not (1). If there are N antennas and several configurations with Nsh pads shared between the configurations the N first lines correspond to the first configuration, the lines N-Nsh+1 to 2*N-Nsh correspond to the second configuration, etc...

As an example of configuration file here is the begining of the input file used to optimize the array represented in Fig.6 of Boone 2001.
This is a multiconfiguration case: 2 configurations are optimized to be complementary.

! Sat Jan 27 12:29:26 2001
64 / nb of ant
2 / nb of conf
44 / nb of common ant
84672.0 / nb of visibilities
-23.0 / site latitude
0.20 / opacity
-10.0 / source declination
-3.0 -0.05 / initial hour angle
6.00 0.1 / integration time
0.3 / hour angle sample interval
700.0 170. / maximal baseline
1.0 / tolerance
700.0 / max baseline for model
12.0 / diameter
15.0 / minimum distance between antennas
12.0 12.0/ minimum baseline
12.0 / min baseline for model
10.5 / mask radius
0.0 / minimum distance from map center
50.0 / maximum authorized displacement
sitemapzoom2.fit / name of map file
10.0 / x pixel size of map
10.0 / y pixel size of map
505.0 / x center of map
505.0 / y center of map
700.0 / fwhm of model
1 / map as background
     -135.000      115.000       0
      205.000      185.000       0
      75.0000     -245.000       0
      275.000     -155.000       0
     -185.000      205.000       0
      65.0000      325.000       0
etc...

OPTIMIZATION SOFTWARE