KPG1_LOGAx

Takes the logarithm to an arbitrary base of an array and its variance

Description:

This routine fills the output array pixels with the results of taking the logarithm of the pixels of the input array to the base specified, i.e. New_value = Log Old_value. Base If the input pixel is negative, then a bad pixel value is used for the output value.

To find the logarithm to any base, the following algorithm is used, providing the base is positive and not equal to one:

New_Value = Log Old_Value / Log Base e e

If variance is present it is computed as: 2 New_Variance = Old_Variance / ( Old_value log Base ) e

Invocation

CALL KPG1_LOGAx( BAD, EL, INARR, VAR, INVAR, BASE, OUTARR, OUTVAR, NERR, NERRV, STATUS )

Arguments

BAD = LOGICAL (Given)
Whether to check for bad values in the input array.
EL = INTEGER (Given)
Number of elements in the input output arrays.
INARR( EL ) = ? (Given)
Array containing input image data.
VAR = LOGICAL (Given)
If .TRUE., there is a variance array to process.
INVAR( EL ) = ? (Given)
Array containing input variance data, when VAR = .TRUE..
BASE = DOUBLE PRECISION (Given)
Base of logarithm to be used. It must be a positive number.
OUTARR( EL ) = ? (Write)
Array containing results of processing the input data.
OUTVAR( EL ) = ? (Write)
Array containing results of processing the input variance data, when VAR = .TRUE..
NERR = INTEGER (Returned)
Number of numerical errors which occurred while processing the data array.
NERRV = INTEGER (Returned)
Number of numerical errors which occurred while processing the variance array, when VAR = .TRUE..
STATUS = INTEGER (Given)
Global status value.

Notes: