### changeset 11984:b4986fecdc53release-3-2-x

author Marco Caliari Thu, 11 Jun 2009 07:13:19 +0200 52b9155fa58a bdc383a457fb scripts/ChangeLog scripts/general/quadgk.m 2 files changed, 9 insertions(+), 7 deletions(-) [+]
line wrap: on
line diff
```--- a/scripts/ChangeLog
+++ b/scripts/ChangeLog
@@ -1,11 +1,15 @@
+2009-06-10  Marco Caliari <marco.caliari@univr.it>
+
+	* general/quadgk.m: Better waypoint transform.
+
2009-06-09  David Bateman  <dbateman@free.fr>

waypoint transform for x = 0 case.

2009-06-09  Marco Caliari <marco.caliari@univr.it>

-	* general/guadgk.m: Fix doubly infinite transformation to the finite
+	* general/quadgk.m: Fix doubly infinite transformation to the finite
interval.

2009-06-08  Ben Abbott <bpabbott@mac.com>```
```--- a/scripts/general/quadgk.m
@@ -193,18 +193,16 @@
##   g(t)  = t / (1 - t^2)
##   g'(t) =  (1 + t^2) / (1 - t^2) ^ 2
## waypoint transform is then
-      ##   t =  (-1 + sqrt(1 + 4 * g(t) .^ 2)) ./ (2 * g(t))
+      ##   t =  (2 * g(t)) ./ (1 + sqrt(1 + 4 * g(t) .^ 2))
if (!isempty (waypoints))
-	trans = @(x) (-1 + sqrt(1 + 4 * x .^ 2)) ./ (2 * x);
+	trans = @(x) (2 * x) ./ ((1 + sqrt(1 + 4 * x .^ 2));
subs = [-1; trans(waypoints); 1];
-	## The waypoint transform gives NaN for x=0;
-	subs(isnan(subs)) = 0;
else
subs = linspace (-1, 1, 11)';
endif
h = 2;
trans = @(t) t ./ (1 - t.^2);
-      f = @(t) f (trans(t)) .* (1 + t .^ 2) ./ ((1 - t .^ 2) .^ 2);
+      f = @(t) f (t ./ (1 - t .^ 2)) .* (1 + t .^ 2) ./ ((1 - t .^ 2) .^ 2);
elseif (isinf(a))
## Formula defined in Shampine paper as two separate steps. One to
## weaken singularity at finite end, then a second to transform to```