Commit 3373bd8e authored by Raymond Toy's avatar Raymond Toy
Browse files

Rename alpha (beta) to bessel-alpha (bessel-beta)

Prevent confusion that `BETA` is the beta function.  While we're at it
rename `ALPHA` too, along with the `FOO-ITER` versions.
parent e61d3612
Pipeline #2210 passed with stage
in 2 minutes and 31 seconds
......@@ -263,12 +263,12 @@
;; alpha[n](z) = G(n+1,z/2)/z^(n+1)
;; beta[n](z) = G(n+1,z/2)/z^(n+1) - G(n+1,-z/2)/z^(n+1)
(defun alpha (n z)
(defun bessel-alpha (n z)
(let ((n (float n (realpart z))))
(/ (incomplete-gamma-lower (1+ n) (/ z 2))
(expt z (1+ n)))))
(defun alpha-iter (n z alpha-old)
(defun bessel-alpha-iter (n z alpha-old)
(if (zerop n)
;; (1- exp(-z/2))/z.
(/ (- 1 (exp (* z -1/2)))
......@@ -278,13 +278,13 @@
z
(ash 1 n)))))
(defun beta (n z)
(defun bessel-beta (n z)
(let ((n (float n (realpart z))))
(/ (- (incomplete-gamma-lower (1+ n) (/ z 2))
(incomplete-gamma-lower (1+ n) (/ z -2)))
(expt z (1+ n)))))
(defun beta-iter (n z old-beta)
(defun bessel-beta-iter (n z old-beta)
(if (zerop n)
;; integrate(exp(-z*s),s,-1/2,1/2)
;; = (exp(z/2)-exp(-z/2)/z
......@@ -360,10 +360,10 @@
(let ((eps (epsilon (realpart z))))
(an-clrhash)
(do* ((n 0 (+ 1 n))
(term (+ (* (alpha n z) (an n 0 v))
(* (beta n z) (sum-an big-n n v z)))
(+ (* (alpha n z) (an n 0 v))
(* (beta n z) (sum-an big-n n v z))))
(term (+ (* (bessel-alpha n z) (an n 0 v))
(* (bessel-beta n z) (sum-an big-n n v z)))
(+ (* (bessel-alpha n z) (an n 0 v))
(* (bessel-beta n z) (sum-an big-n n v z))))
(sum term (+ sum term)))
((<= (abs term) (* eps (abs sum)))
sum)
......@@ -376,10 +376,10 @@
(let ((eps (epsilon (realpart z))))
(an-clrhash)
(do* ((n 0 (+ 1 n))
(alphan (alpha-iter 0 z 0)
(alpha-iter n z alphan))
(betan (beta-iter 0 z 0)
(beta-iter n z betan))
(alphan (bessel-alpha-iter 0 z 0)
(bessel-alpha-iter n z alphan))
(betan (bessel-beta-iter 0 z 0)
(bessel-beta-iter n z betan))
(term (+ (* alphan (an n 0 v))
(* betan (sum-an big-n n v z)))
(+ (* alphan (an n 0 v))
......
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