5 files changed, 23 insertions, 11 deletions

diff --git a/doc/nissy.1 b/doc/nissy.1
index c467a2b..7b92e8c 100644
--- a/doc/nissy.1
+++ b/doc/nissy.1
@@ -137,6 +137,8 @@ steps, for examples EOs that finish with F\(aq, with this options they are not.
 .
 .It Fl c
 Display only the number of solutions found, not the solutions themselves.
+.It Fl L
+Look for solutions on both normal and inverse scramble, without NISS (linear).
 .
 .It Fl m Ar min
 Only look for solution that are at least
diff --git a/src/commands.c b/src/commands.c
index f01edfd..1e5dd07 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -210,7 +210,7 @@ solve_parse_args(int c, char **v)
         a->opts->max_solutions = 1;
         a->opts->nthreads      = 1;
         a->opts->optimal       = -1;
-        a->opts->can_niss      = false;
+        a->opts->nisstype      = NORMAL;
         a->opts->verbose       = false;
         a->opts->all           = false;
         a->opts->print_number  = true;
@@ -272,7 +272,10 @@ solve_parse_args(int c, char **v)
                         a->opts->optimal = val;
                         infinitesols = true;
                 } else if (!strcmp(v[i], "-N")) {
-                        a->opts->can_niss = true;
+                        a->opts->nisstype = NISS;
+                } else if (!strcmp(v[i], "-L")) {
+                        if (a->opts->nisstype != NISS)
+                                a->opts->nisstype = LINEAR;
                 } else if (!strcmp(v[i], "-i")) {
                         a->scrstdin = true;
                 } else if (!strcmp(v[i], "-v")) {
diff --git a/src/cubetypes.h b/src/cubetypes.h
index 66839ca..b082518 100644
--- a/src/cubetypes.h
+++ b/src/cubetypes.h
@@ -70,6 +70,12 @@ trans
         bu_mirror, br_mirror, bd_mirror, bl_mirror,
 } Trans;
 
+typedef enum
+niss_type
+{
+        NORMAL, LINEAR, NISS
+} NissType;
+
 
 /* Typedefs ******************************************************************/
 
@@ -291,7 +297,7 @@ solveoptions
         int                       max_solutions;
         int                       nthreads;
         int                       optimal;
-        bool                      can_niss;
+        NissType                  nisstype;
         bool                      verbose;
         bool                      all;
         bool                      print_number;
diff --git a/src/solve.c b/src/solve.c
index 44550cc..39437fb 100644
--- a/src/solve.c
+++ b/src/solve.c
@@ -97,7 +97,7 @@ dfs(DfsArg *arg)
                 invert_branch(arg);
         dfs_branch(arg);
 
-        if (arg->opts->can_niss && !arg->niss && niss_makes_sense(arg))
+        if (arg->opts->nisstype == NISS && !arg->niss && niss_makes_sense(arg))
                 dfs_niss(arg);
 
         if (sw)
@@ -193,7 +193,7 @@ dfs_stop(DfsArg *arg)
         bool b;
 
         lowerbound = arg->step->estimate(arg);
-        if (arg->opts->can_niss && !arg->niss)
+        if (arg->opts->nisstype == NISS && !arg->niss)
                 lowerbound = MIN(1, lowerbound);
 
         if (arg->current_alg->len + lowerbound > arg->d) {
@@ -330,7 +330,7 @@ multidfs(Cube c, Trans tr, Step *s, SolveOptions *opts, AlgList *sols, int d)
                 alg = new_alg("");
                 append_move(alg, s->moveset->sorted_moves[i], false);
                 append_alg(start, alg);
-                if (opts->can_niss) {
+                if (opts->nisstype == NISS || opts->nisstype == LINEAR) {
                         alg->inv[0] = true;
                         append_alg(start, alg);
                 }
@@ -458,7 +458,7 @@ solve_2phase(Cube cube, int nthreads)
         opts1.max_solutions = 20;
         opts1.nthreads      = nthreads;
         opts1.optimal       = 3;
-        opts1.can_niss      = false;
+        opts1.nisstype      = NORMAL;
         opts1.verbose       = false;
         opts1.all           = true;
 
@@ -466,7 +466,7 @@ solve_2phase(Cube cube, int nthreads)
         opts2.max_moves     = 19;
         opts2.max_solutions = 1;
         opts2.nthreads      = nthreads;
-        opts2.can_niss      = false;
+        opts2.nisstype      = NORMAL;
         opts2.verbose       = false;
 
         /* We skip step1 if it is solved on any axis */
diff --git a/src/steps.c b/src/steps.c
index bdcbd2a..6754d22 100644
--- a/src/steps.c
+++ b/src/steps.c
@@ -1678,9 +1678,10 @@ prepare_step(Step *step, SolveOptions *opts)
 {
         int i;
 
-        if (step->final && opts->can_niss) {
-                opts->can_niss = false;
-                fprintf(stderr, "Step is final, NISS not used (-n ignored)\n");
+        if (step->final && opts->nisstype != NORMAL) {
+                opts->nisstype = NORMAL;
+                fprintf(stderr, "Step is final, NISS not used"
+                                " (-N and -L ignored)\n");
         }
 
         for (i = 0; i < step->ntables; i++) {