Add OB_RANDOM_SEED environment variable to specify seed for PRNG

openbabel · Jun 16, 2020 · 301390e · 301390e
1 parent f535334
commit 301390e
Show file tree

Hide file tree

Showing 4 changed files with 22 additions and 0 deletions.
diff --git a/doc/obabel.1 b/doc/obabel.1
@@ -341,6 +341,11 @@ Conversion from a SMI file in STDIN to a Mol2 file written to STDOUT:
 .Dl "obabel \-ismi \-omol2"
 Split a multi-molecule file into new1.smi, new2.smi, etc.:
 .Dl "obabel infile.mol -Onew.smi \-m"
+.Sh ENVIRONMENT
+.Bl -tag -width flag
+.It Ev OB_RANDOM_SEED
+Specify seed for pseudo random number generator.
+If not specified, random seed is used.
 .Sh SEE ALSO
 .Xr obenergy 1 ,
 .Xr obfit 1 ,

diff --git a/doc/obdistgen.1 b/doc/obdistgen.1
@@ -14,6 +14,11 @@ Generates SDFs with distance geometry.
 .Pp
 Generate rough 3D coordinates for molecule.smi and write
 it to molecule.sdf
+.Sh ENVIRONMENT
+.Bl -tag -width flag
+.It Ev OB_RANDOM_SEED
+Specify seed for pseudo random number generator.
+If not specified, random seed is used.
 .Sh SEE ALSO
 .Xr obgen 1 .
 .Pp

diff --git a/doc/obgen.1 b/doc/obgen.1
@@ -32,6 +32,11 @@ Generate 3D coordinates for the molecule(s) in file test.smi:
 Generate 3D coordinates for the molecule(s) in file test.smi using the
 UFF forcefield:
 .Dl "obgen -ff UFF test.smi"
+.Sh ENVIRONMENT
+.Bl -tag -width flag
+.It Ev OB_RANDOM_SEED
+Specify seed for pseudo random number generator.
+If not specified, random seed is used.
 .Sh SEE ALSO
 .Xr obabel 1 ,
 .Xr obminimize 1 ,

diff --git a/src/rand.cpp b/src/rand.cpp
@@ -19,6 +19,8 @@ GNU General Public License for more details.
 
 #include "rand.h"
 
+#include <cstdlib>
+
 #if TIME_WITH_SYS_TIME
 #include <sys/time.h>
 #include <ctime>
@@ -36,6 +38,11 @@ namespace OpenBabel
 
   void OBRandom::Reset()
   {
+    auto ob_random_seed = std::getenv("OB_RANDOM_SEED");
+    if (ob_random_seed) {
+      this->Seed(std::atoll(ob_random_seed));
+      return;
+    }
 #if defined(WIN32) || defined(__MINGW32__)
     // for VC++ do it this way
     time_t ltime;