SURFLIB_READ

This routine reads IP data from a text file and stores it in a multi-dimensional array. The format of the file is: Any line starting with the string ’FAST’ is assumed to be specifying the angle between 0 degrees on the waveplate and the angle to the fast axis. This is wavelength dependent. The line should be of the format

FAST filter angle

eg “FAST 450 -3.0”

The list of valid filter names is passed in to the routine. An error is raised if a fast axis angle has not been specified for each filter.

For each bolometer the following information is required:

BolName P0 P0_Err Pslope_Err Theta0 Theta0_Err ThetaSlope ThetaSlope_Err

BolName	Name of bolometer (eg H7,G12..)
P0	IP percentage polarization at the horizon
P0Err	Error in P0
PSlope	Gradient in P (ie P = P0 $+$ Pslope $*$ Elevation)
PSlopeErr	Error in PSlope
Theta0	polarization angle of IP (degrees)
Theta0Err	Error in polarisation angle
ThetaSlope	Gradient in Theta (ie Theta = Theta0 $+$ ThetaSlope $*$ El)
ThSlErr	Error in ThetaSlope

For example: H7 2.0 0.01 0.02 0.01 167 2 1.0 0.01

{ is the comment character. Blank lines are ignored. The columns must be space separated.

All angles are converted to radians before further processing (including Pslope which is in degrees $^{- 1}$ )

CALL SURFLIB_READ_IPFILE( FD, NUM_CHAN, NUM_ADC, N_FILT, FILTERS, FAST_ANG, BOL_IP_DATA, STATUS)

FD = FILE (Given)

Identifier to the open file (opened for read access)

NUM_CHAN = INTEGER (Given)

Number of available bolometer channels

NUM_ADC = INTEGER (Given)

Number of available AtoD cards

N_FILT = INTEGER (Given)

Number of filters requested

FILTERS( N_FILT ) = CHARACTER (Given)

Array of requested filter names

FAST_ANG( N_FILT ) = REAL (Returned)

Fast axis angle for each filter. Will contain bad values if no angle was found

BOL_IP_DATA(8, NUM_CHAN, NUM_ADC) = REAL (Returned)

The IP data. This array contains the ip data for each bolometer (specified by a combination of CHAN and ADC). The 4 slices represent: P0, Pslope, Theta0 and ThetaSlope The last 4 slices contain the corresponding variance All angles are converted to radians (Pslope has to be converted from /degree to /radian).

SURFLIB_READ_IPFILE

Description:

Invocation

Arguments