[gnumeric] dpois_raw: handle x=0.

[Morten Welinder <mortenw src gnome org>]

commit 025f887cb4564e1531f658d53569d7ab40558068
Author: Morten Welinder <terra gnome org>
Date:   Fri Nov 1 20:05:50 2013 -0400

    dpois_raw: handle x=0.

 ChangeLog      |    4 ++++
 src/mathfunc.c |    2 +-
 2 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 2189ed0..6df135d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2013-11-01  Morten Welinder  <terra gnome org>
+
+       * src/mathfunc.c (dpois_raw): Handler x=0 as in newer R.
+
 2013-10-31  Morten Welinder  <terra gnome org>
 
        * src/mathfunc.c (qgamma): Flip tail for high values of p.  This
diff --git a/src/mathfunc.c b/src/mathfunc.c
index 7b4db5a..a9e9b36 100644
--- a/src/mathfunc.c
+++ b/src/mathfunc.c
@@ -1080,7 +1080,7 @@ static gnm_float dpois_raw(gnm_float x, gnm_float lambda, gboolean give_log)
     if (lambda == 0) return( (x == 0) ? R_D__1 : R_D__0 );
     if (!gnm_finite(lambda)) return R_D__0;
     if (x < 0) return( R_D__0 );
-    if (x < lambda * GNM_MIN) return(R_D_exp(-lambda) );
+    if (x <= lambda * GNM_MIN) return(R_D_exp(-lambda) );
     if (lambda < x * GNM_MIN) return(R_D_exp(-lambda + x*gnm_log(lambda) -lgamma1p (x)));
     return(R_D_fexp( M_2PIgnum*x, -stirlerr(x)-bd0(x,lambda) ));
 }