Changeset d795ba718dc53f591c82994811f50250aceec1d7
 Timestamp:
 04/11/12 20:15:47 (2 years ago)
 Author:
 Raymond Toy <toy.raymond@…>
 Children:
 6ab5226ca3e32b443d87934ec138ff0efc8aaecc
 Parents:
 c0e12ddf6b61f571555d46c6f168e6bebabc80b1
 gitcommitter:
 Raymond Toy <toy.raymond@…> (04/11/12 20:15:47)
 Message:

Add TODO list for besselj.
 Files:

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rc0e12d

rd795ba


376  376  (format t " term = ~S~%" term) 
377  377  (format t " sum = ~S~%" sum)))))) 
378   
 378  
 379  ;; TODO: 
 380  ;; o For z <= 1 use the series. 
 381  ;; o Currently accuracy is not good for large z and halfinteger 
 382  ;; order. 
 383  ;; o For real v and z, return a real number instead of complex. 
 384  ;; o Handle the case of Re(z) < 0. (The formulas are for Re(z) > 0: 
 385  ;; bessel_j(v,z*exp(m*%pi*%i)) = exp(m*v*%pi*%i)*bessel_j(v, z) 
 386  ;; o The paper suggests using 
 387  ;; bessel_i(v,z) = exp(v*%pi*%i/2)*bessel_j(v, %i*z) 
 388  ;; when Im(z) >> Re(z) 
 389  ;; 
379  390  (defun besselj (v z) 
380  391  (let ((vv (ftruncate v))) 
… 
… 

383  394  (integerbesseljexparc v z)) 
384  395  (t 
 396  ;; Need to finetune the value of bign. 
385  397  (let ((bign 100) 
386  398  (vpi (* v (floatpi (realpart z))))) 