[R-gregmisc-users] SF.net SVN: r-gregmisc:[2021] pkg/gtools/tests/test_ddirichlet.R

[<wa...@us...>]

Revision: 2021
          http://sourceforge.net/p/r-gregmisc/code/2021
Author:   warnes
Date:     2015-05-23 22:21:39 +0000 (Sat, 23 May 2015)
Log Message:
-----------
Add regression test ddirichlet() bug for x[i]=0, alpha[i]=1:
ddirichlet(x, alpha) was returning NA rather than 0.

Added Paths:
-----------
    pkg/gtools/tests/test_ddirichlet.R

Added: pkg/gtools/tests/test_ddirichlet.R
===================================================================
--- pkg/gtools/tests/test_ddirichlet.R	                        (rev 0)
+++ pkg/gtools/tests/test_ddirichlet.R	2015-05-23 22:21:39 UTC (rev 2021)
@@ -0,0 +1,14 @@
+## Bug reported by John Nolan:
+
+##
+## Whenever the pair (x[i], a[i]) == (0,1), NA would be returned, due
+## to an internal computation of ( 0 * -Inf ) => NaN
+##
+## The code now checks for this particular issue and sets the value of
+## ( 0 * -Inf ) to 0, which is correct for this calculation.
+##
+x = c(0,0,1)
+alpha = c(1,2,3)
+
+stopifnot( ddirichlet(x=x, alpha=alpha) == 0 )
+

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