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Finding the Rate of Change of a Mapping Output

The AST_RATE function can be used to find the rate of change of any Mapping output with respect to any Mapping input, at a given input position. The method used produces good accuracy (typically a relative error of 10E-10 or less) but may require the Mapping to be evaluated 100 or more times. An estimate of the second derivative is also produced by this function.



next up previous 264
Next: Reporting Coordinate Transformations
Up: Inter-Relating Coordinate Systems (Mappings)
Previous: Inverting Mappings

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
24th May 2011
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2009 Science \& Technology Facilities Council