Module nic_rem_persist

When run under python, check validity of input parameters. For unspecified *_lo parameters, the
    user will be given the option of typing in a value or accepting the default value. For an unspecified
    model(mask) file, will try to get file name from PMODFILE(PMSKFILE) from input file header, otherwise
    will get default value from persutil.           

@param calcfile: name of PED file
@type calcfile: string
@param targfile: name of CAL file
@type targfile: string
@param persist_lo: minimum allowed value of the persistence 
@type persist_lo: Float32
@param used_lo: minimum allowed value of the fraction of pixels used 
@type used_lo: Float32
@param persist_model: filename containing persistence frame (ring median of)
@type persist_model:  string
@param persist_mask: filename containing pixel mask 
@type persist_mask:  string

@return: persist_lo, used_lo, persist_model, persist_mask
@rtype: float, float, string, string

When run from linux command line, verify that each parameter is valid.

Parameters:

• calcfile (string) - name of ped file
• targfile (string) - name of cal file
• persist_lo (Float32) - minimum allowed value of the persistence
• used_lo (Float32) - minimum allowed value of the fraction of pixels used

Returns: float, float

persist_lo, used_lo

Make an annular mask footprint for use in ndimage.median_filter to create a ring median image.
    Sets all pixels between rin and rout to 1.

@param rin: inner radius
@type rin: integer
@param rout: outer radius
@type rout: integer

@return: mask
@rtype: ndarray

version of nicmos iterstat: calculate sigma-clipped mean
     and standart deviation

@param clip: number of std to use in sigma clipping  
@type clip:  Float32
@param d: array of values to sigma clip
@type clip:  Float32

@return:  clipped mean, clipped std
@rtype:  float, float    

Return the median of the array y, ignoring masked elements.

Parameters:

• y (Float32) - array of values [2d]
• mask (Int32) - array of ones or zeros (0 indicates a good value) [2d]

Returns: float

median of y, ignoring masked elements