diff --git a/src/gnu/CMakeLists.txt b/src/gnu/CMakeLists.txt
index 3442a19f03..a8da27eb2d 100644
--- a/src/gnu/CMakeLists.txt
+++ b/src/gnu/CMakeLists.txt
@@ -1,5 +1,6 @@
 add_library(
   nrngnu STATIC
+  Geom.cpp
   HypGeom.cpp
   MCellRan4RNG.cpp
   mcran4.cpp
diff --git a/src/gnu/Geom.cpp b/src/gnu/Geom.cpp
new file mode 100755
index 0000000000..6f90799e3b
--- /dev/null
+++ b/src/gnu/Geom.cpp
@@ -0,0 +1,29 @@
+/* 
+Copyright (C) 1988 Free Software Foundation
+    written by Dirk Grunwald (grunwald@cs.uiuc.edu)
+
+This file is part of the GNU C++ Library.  This library is free
+software; you can redistribute it and/or modify it under the terms of
+the GNU Library General Public License as published by the Free
+Software Foundation; either version 2 of the License, or (at your
+option) any later version.  This library is distributed in the hope
+that it will be useful, but WITHOUT ANY WARRANTY; without even the
+implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+PURPOSE.  See the GNU Library General Public License for more details.
+You should have received a copy of the GNU Library General Public
+License along with this library; if not, write to the Free Software
+Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+#ifdef __GNUG__
+#pragma implementation
+#endif
+#include "Random.h"
+#include "Geom.h"
+
+double Geometric::operator()()
+{
+    int samples;
+    for (samples = 1; pGenerator -> asDouble() < pMean; samples++);
+    return((double) samples);
+}
+
diff --git a/src/gnu/Geom.h b/src/gnu/Geom.h
new file mode 100755
index 0000000000..cc0d8dcee6
--- /dev/null
+++ b/src/gnu/Geom.h
@@ -0,0 +1,44 @@
+// This may look like C code, but it is really -*- C++ -*-
+/* 
+Copyright (C) 1988 Free Software Foundation
+    written by Dirk Grunwald (grunwald@cs.uiuc.edu)
+
+This file is part of the GNU C++ Library.  This library is free
+software; you can redistribute it and/or modify it under the terms of
+the GNU Library General Public License as published by the Free
+Software Foundation; either version 2 of the License, or (at your
+option) any later version.  This library is distributed in the hope
+that it will be useful, but WITHOUT ANY WARRANTY; without even the
+implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+PURPOSE.  See the GNU Library General Public License for more details.
+You should have received a copy of the GNU Library General Public
+License along with this library; if not, write to the Free Software
+Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+#pragma once
+#include "Random.h"
+
+class Geometric: public Random {
+protected:
+    double pMean;
+public:
+    Geometric(double mean, RNG *gen);
+
+    double mean();
+    double mean(double x);
+
+    virtual double operator()();
+
+};
+
+
+inline Geometric::Geometric(double mean, RNG *gen) : Random(gen)
+{
+  pMean = mean;
+}
+
+
+inline double Geometric::mean() { return pMean; }
+inline double Geometric::mean(double x) {
+  double tmp = pMean; pMean = x; return tmp;
+}
diff --git a/src/gnu/distributions.hpp b/src/gnu/distributions.hpp
index c633c8891c..e8669326e5 100644
--- a/src/gnu/distributions.hpp
+++ b/src/gnu/distributions.hpp
@@ -46,20 +46,6 @@ class Erlang: public Random {
     std::gamma_distribution<> d;
 };
 
-class Geometric: public Random {
-public:
-    Geometric(double mean, RNG *gen)
-        : Random(gen)
-        , d(1 / (mean + 1))
-    {}
-
-    double operator()() override {
-        return 1. + d(*generator());
-    }
-private:
-    std::geometric_distribution<> d;
-};
-
 class LogNormal: public Random {
 public:
     LogNormal(double mean, double variance, RNG *gen)
diff --git a/src/ivoc/ivocrand.cpp b/src/ivoc/ivocrand.cpp
index feba848244..a823de07b4 100644
--- a/src/ivoc/ivocrand.cpp
+++ b/src/ivoc/ivocrand.cpp
@@ -18,6 +18,7 @@
 
 #include <Random.h>
 #include <distributions.hpp>
+#include <Geom.h>
 #include <HypGeom.h>
 #include <NrnRandom123RNG.hpp>
 #include <MCellRan4RNG.hpp>