ENHANCE: RandomUnimodularMat allows for option of entry range

as Random(Integers) only selects from [-10..10].

lib/matrix.gd

@@ -1734,6 +1734,8 @@ DeclareGlobalFunction( "RandomMat" );
 ##  returns a new random mutable <A>m</A><M>\times</M><A>m</A> matrix with integer
 ##  entries that is invertible over the integers.
 ##  Optionally, a random source <A>rs</A> can be supplied.
+##  If the option <A>domain</A> is given, random seection is made from <A>domain</A>, otherwise
+##  from <A>Integers</A>
 ##  <Example><![CDATA[
 ##  gap> m := RandomUnimodularMat(3);
 ##  [ [ -5, 1, 0 ], [ 12, -2, -1 ], [ -14, 3, 0 ] ]

lib/matrix.gi

@@ -3593,8 +3593,13 @@ end );
 #F  RandomUnimodularMat( [rs ,] <m> )  . . . . . . . random unimodular matrix
 ##
 InstallGlobalFunction( RandomUnimodularMat, function ( arg )
-    local  rs, m, mat, c, i, j, k, l, a, b, v, w, gcd;
+local  rs, m, mat, c, i, j, k, l, a, b, v, w, gcd,dom;
 
+    dom:=ValueOption("domain");
+    if dom=fail or dom=false then
+      dom:=Integers;
+    fi;
+
     if Length(arg) >= 1 and IsRandomSource(arg[1]) then
         rs := Remove(arg, 1);
     else
@@ -3626,8 +3631,8 @@ InstallGlobalFunction( RandomUnimodularMat, function ( arg )
             j := Random(rs, 1, m);
         until j <> i;
         repeat
-            a := Random( rs, Integers );
-            b := Random( rs, Integers );
+            a := Random( rs, dom );
+            b := Random( rs, dom );
             gcd := Gcdex( a, b );
         until gcd.gcd = 1;
         v := mat[i];  w := mat[j];
@@ -3640,8 +3645,8 @@ InstallGlobalFunction( RandomUnimodularMat, function ( arg )
             l := Random(rs, 1, m);
         until l <> k;
         repeat
-            a := Random( rs, Integers );
-            b := Random( rs, Integers );
+            a := Random( rs, dom );
+            b := Random( rs, dom );
             gcd := Gcdex( a, b );
         until gcd.gcd = 1;
         for i  in [1..m]  do