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Timestamp:
03/21/12 22:24:48 (2 years ago)
Author:
Raymond Toy <toy.raymond@…>
Children:
e10e402d446339130042607357b0129b35a1faa7
Parents:
4b332ed2140e56c6fcaa689e6b8a48be36c988f6
git-committer:
Raymond Toy <toy.raymond@…> (03/21/12 22:24:48)
Message:

Handle the case of negative v in exp-integral-e(v, z). Add tests.

Files:
1 modified

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  • qd-gamma.lisp

    r4b332e r1d9ec0  
    528528  ;; 
    529529  ;; 
    530   (cond ((< (abs z) 1) 
     530  (cond ((and (realp v) (minusp v)) 
     531         ;; E(-v, z) = z^(-v-1)*incomplete_gamma_tail(v+1,z) 
     532         (let ((-v (- v))) 
     533           (* (expt z (- v 1)) 
     534              (incomplete-gamma-tail (+ -v 1) z)))) 
     535        ((< (abs z) 1) 
    531536         ;; Use series for small z 
    532537         (s-exp-integral-e v z))