ENHANCE: RandomUnimodularMat allows for option of entry range

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

lib/matrix.gd

@@ -1671,17 +1671,23 @@ DeclareGlobalFunction( "RandomMat" );
 ##
 ##  <#GAPDoc Label="RandomUnimodularMat">
 ##  <ManSection>
-##  <Func Name="RandomUnimodularMat" Arg='[rs ,] m'/>
+##  <Func Name="RandomUnimodularMat" Arg='[rs ,] m [:random:=d]'/>
 ##
 ##  <Description>
 ##  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.
+##  Optionally, a random source <A>rs</A> can be supplied. If the
+##  option <C>random</C> is given, selection of random numbers is made from
+##  <A>d</A> (allowing for larger coefficients), otherwise from 
+##  <Ref Var="Integers"/> (for which random selection is bounded).
 ##  <Example><![CDATA[
 ##  gap> m := RandomUnimodularMat(3);
 ##  [ [ -5, 1, 0 ], [ 12, -2, -1 ], [ -14, 3, 0 ] ]
 ##  gap> m^-1;
 ##  [ [ -3, 0, 1 ], [ -14, 0, 5 ], [ -8, -1, 2 ] ]
+##  gap> m := RandomUnimodularMat(3:random:=[-100..100]);
+##  [ [ -2795335, 8733, 6466434 ], [ -19667053, 61444, 45495692 ],
+##    [ 37158478, -116088, -85958515 ] ]
 ##  ]]></Example>
 ##  </Description>
 ##  </ManSection>

lib/matrix.gi

@@ -3651,8 +3651,13 @@ 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("random");
+    if dom=fail or dom=false then
+      dom:=Integers;
+    fi;
+
     if Length(arg) >= 1 and IsRandomSource(arg[1]) then
         rs := Remove(arg, 1);
     else
@@ -3684,8 +3689,8 @@ 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];
@@ -3698,8 +3703,8 @@ 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