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;; Index lookup and acceleration
;; Liam Healy, Sun Nov  4 2007 - 18:09
;; Time-stamp: <2008-12-26 11:18:49EST lookup.lisp>
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;; $Id$
(defmobject acceleration "gsl_interp_accel"
  ()
  "acceleration for interpolation"			; FDL
  "Make an accelerator object, which is a
   kind of iterator for interpolation lookups.  It tracks the state of
   lookups, thus allowing for application of various acceleration
   strategies.")

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(defmfun interpolation-search (x-array x low-index high-index)
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  ((x-array :pointer) (x :double) (low-index sizet) (high-index sizet))
  :c-return sizet
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  :documentation			; FDL
  "Find the index i of the array x-array such
   that x-array[i] <= x < x-array[i+1].  The index is searched for
   in the range [low-index, high-index].")

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(defmfun accelerated-interpolation-search (x-array x acceleration)
  "gsl_interp_accel_find"
  ((acceleration :pointer) (x-array :pointer) (x :double))
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  :c-return sizet
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  :documentation			; FDL
  "Search the data array x-array of size, using the given acceleration.
   This is how lookups are performed during evaluation of an interpolation.  The
   function returns an index i such that x_array[i] <= x < x_array[i+1]}.")