10 files changed, 58 insertions, 21 deletions

diff --git a/configure.sh b/configure.sh
index aac6444..ec0343a 100755
--- a/configure.sh
+++ b/configure.sh
@@ -14,7 +14,9 @@
 # The string "architecture" must be one of "AVX2", "NEON" or "PORTABLE".
 #
 # THREADS=n
-# Choose how many threads to use for multi-threaded oerations.
+# The maximum number of threads to use for multi-threaded operations.
+# This is also used as default value in case an operation allows
+# specifying how many threads to use.
 # By default, 8 threads will be used (TODO: in the future this will be
 # determined base on the system).
 # The number n must be between 1 and 128.
diff --git a/python/example.py b/python/example.py
index fdea2d4..b939183 100644
--- a/python/example.py
+++ b/python/example.py
@@ -23,7 +23,7 @@ data = bytearray(open("tables/" + solver, "rb").read())
 cube = nissy.applymoves(nissy.solved_cube, "U F R2");
 
 # Solve!
-solutions = nissy.solve(cube, solver, nissy.nissflag_normal, 0, 9, 3, -1, data)
+solutions = nissy.solve(cube, solver, nissy.nissflag_normal, 0, 9, 3, -1, 4, data)
 
 # Print the solutions, one per line
 print("Found ", len(solutions), " solutions:")
diff --git a/python/nissy_module.c b/python/nissy_module.c
index 2357b90..947d06f 100644
--- a/python/nissy_module.c
+++ b/python/nissy_module.c
@@ -306,7 +306,8 @@ checkdata(PyObject *self, PyObject *args)
 }
 
 PyDoc_STRVAR(solve_doc,
-"solve(cube, solver, nissflag, minmoves, maxmoves, maxsolutions, optimal, data)\n"
+"solve(cube, solver, nissflag, minmoves, maxmoves, maxsolutions,"
+" optimal, threads, data)\n"
 "--\n\n"
 "Solves the given 'cube' with the given 'solver' and other parameters."
 "See the documentation for libnissy (in nissy.h) for details.\n"
@@ -319,6 +320,7 @@ PyDoc_STRVAR(solve_doc,
 "  - maxsolution: the maximum number of solutions to return\n"
 "  - optimal: the largest number of moves from the shortest solution"
 "(set to -1 to ignore)\n"
+"  - threads: the number of threads to use (0 for default)\n"
 "  - data: a bytearray containing the data for the solver\n"
 "\n"
 "Returns: a list with the solutions found\n"
@@ -328,20 +330,20 @@ solve(PyObject *self, PyObject *args)
 {
         long long result;
         unsigned nissflag, minmoves, maxmoves, maxsolutions;
-        int optimal, i, j, k;
+        int optimal, i, j, k, threads;
         const char *cube, *solver;
         char solutions[MAX_SOLUTIONS_SIZE];
         long long stats[NISSY_SIZE_SOLVE_STATS];
         PyByteArrayObject *data;
         PyObject *list, *item;
 
-        if (!PyArg_ParseTuple(args, "ssIIIIiY", &cube, &solver, &nissflag,
-            &minmoves, &maxmoves, &maxsolutions, &optimal, &data))
+        if (!PyArg_ParseTuple(args, "ssIIIIiiY", &cube, &solver, &nissflag,
+            &minmoves, &maxmoves, &maxsolutions, &optimal, &threads, &data))
                 return NULL;
 
         Py_BEGIN_ALLOW_THREADS
         result = nissy_solve(cube, solver, nissflag, minmoves, maxmoves,
-            maxsolutions, optimal, data->ob_alloc, data->ob_bytes,
+            maxsolutions, optimal, threads, data->ob_alloc, data->ob_bytes,
             MAX_SOLUTIONS_SIZE, solutions, stats);
         Py_END_ALLOW_THREADS
 
diff --git a/shell/shell.c b/shell/shell.c
index e548fd6..5a2d283 100644
--- a/shell/shell.c
+++ b/shell/shell.c
@@ -28,6 +28,7 @@
 #define FLAG_MAXMOVES     "-M"
 #define FLAG_OPTIMAL      "-O"
 #define FLAG_MAXSOLUTIONS "-n"
+#define FLAG_THREADS      "-t"
 
 #define INFO_CUBEFORMAT(cube) cube " must be given in B32 format."
 #define INFO_MOVESFORMAT "The accepted moves are U, D, R, L, F and B, " \
@@ -54,6 +55,7 @@ typedef struct {
         unsigned maxmoves;
         unsigned optimal;
         unsigned maxsolutions;
+        unsigned threads;
 } args_t;
 
 static int64_t compose_exec(args_t *);
@@ -88,6 +90,7 @@ static bool set_minmoves(int, char **, args_t *);
 static bool set_maxmoves(int, char **, args_t *);
 static bool set_optimal(int, char **, args_t *);
 static bool set_maxsolutions(int, char **, args_t *);
+static bool set_threads(int, char **, args_t *);
 static bool set_id(int, char **, args_t *);
 
 static uint64_t rand64(void);
@@ -113,6 +116,7 @@ struct {
         OPTION(FLAG_MAXMOVES, 1, set_maxmoves),
         OPTION(FLAG_OPTIMAL, 1, set_optimal),
         OPTION(FLAG_MAXSOLUTIONS, 1, set_maxsolutions),
+        OPTION(FLAG_THREADS, 1, set_threads),
         OPTION(NULL, 0, NULL)
 };
  
@@ -193,9 +197,10 @@ struct {
                 "solve",
                 "solve " FLAG_SOLVER " SOLVER"
                 "[" FLAG_MINMOVES " n] [" FLAG_MAXMOVES " N] "
-                FLAG_CUBE " CUBE",
+                FLAG_CUBE " CUBE"
+                FLAG_THREADS " T",
                 "Solve the given CUBE using SOLVER, "
-                "using at least n and at most N moves. "
+                "using at least n and at most N moves, and T threads. "
                 INFO_CUBEFORMAT("CUBE"),
                 solve_exec
         ),
@@ -475,7 +480,7 @@ solve_exec(args_t *args)
 
         ret = nissy_solve(
             args->cube, args->str_solver, nissflag, args->minmoves,
-            args->maxmoves, args->maxsolutions, args->optimal,
+            args->maxmoves, args->maxsolutions, args->optimal, args->threads,
             size, buf, SOLUTIONS_BUFFER_SIZE, solutions, stats);
 
         free(buf);
@@ -557,6 +562,7 @@ parse_args(int argc, char **argv, args_t *args)
                 .maxmoves = 20,
                 .optimal = -1,
                 .maxsolutions = 1,
+                .threads = 0,
         };
 
         if (argc == 0) {
@@ -728,6 +734,12 @@ set_maxsolutions(int argc, char **argv, args_t *args)
         return parse_uint(argv[0], &args->maxsolutions);
 }
 
+static bool
+set_threads(int argc, char **argv, args_t *args)
+{
+        return parse_uint(argv[0], &args->threads);
+}
+
 void
 log_stderr(const char *str, ...)
 {
diff --git a/src/nissy.c b/src/nissy.c
index f933cab..5d009ba 100644
--- a/src/nissy.c
+++ b/src/nissy.c
@@ -489,6 +489,7 @@ nissy_solve(
         unsigned maxmoves,
         unsigned maxsols,
         int optimal,
+        int threads,
         unsigned long long data_size,
         const char data[data_size],
         unsigned sols_size,
@@ -499,6 +500,7 @@ nissy_solve(
         cube_t c;
         long long parse_ret;
         uint8_t h, k;
+        int t;
 
         if (solver == NULL) {
                 LOG("Error: 'solver' argument is NULL\n");
@@ -522,10 +524,22 @@ nissy_solve(
                 return 0;
         }
 
+        t = threads == 0 ? THREADS : threads;
+        if (t < 0) {
+                LOG("solve: 'threads' is negative. Please provide a "
+                    "number of threads between 1 and %d\n", THREADS);
+                return NISSY_ERROR_OPTIONS;
+        } 
+        if (t > THREADS) {
+                LOG("solve: 'threads' is above the maximum value of %d\n",
+                    THREADS);
+                return NISSY_ERROR_OPTIONS;
+        }
+
         if (!strncmp(solver, "h48", 3)) {
                 parse_ret = parse_h48_solver(solver, &h, &k);
                 if (parse_ret == NISSY_OK)
-                        return solve_h48(c, minmoves, maxmoves, maxsols,
+                        return solve_h48(c, minmoves, maxmoves, maxsols, t,
                                 data_size, data, sols_size, sols, stats);
                 else
                         return parse_ret;
diff --git a/src/nissy.h b/src/nissy.h
index 8394fad..94c604c 100644
--- a/src/nissy.h
+++ b/src/nissy.h
@@ -259,6 +259,9 @@ Parameters:
    maxsols   - The maximum number of solutions.
    optimal   - If set to a non-negative value, the maximum number of moves
                above the optimal solution length.
+   threads   - The number of threads to use. Must be less than or equalt to
+               the value of the compile-time constant THREADS. If set to 0,
+               the default value THREADS will be used.
    data_size - The size of the data buffer.
    data      - The data for the solver. Can be computed with gendata.
    sols_size - The size of the solutions buffer.
@@ -286,6 +289,7 @@ nissy_solve(
         unsigned maxmoves,
         unsigned maxsolutions,
         int optimal,
+        int threads,
         unsigned long long data_size,
         const char data[data_size],
         unsigned sols_size,
diff --git a/src/solvers/h48/solve.h b/src/solvers/h48/solve.h
index 8666007..0969c45 100644
--- a/src/solvers/h48/solve.h
+++ b/src/solvers/h48/solve.h
@@ -38,6 +38,7 @@ typedef struct {
         int64_t nodes_visited;
         int64_t table_fallbacks;
         int64_t table_lookups;
+        int threads;
         int ntasks;
         solve_h48_task_t *tasks;
         int thread_id;
@@ -62,7 +63,7 @@ STATIC int64_t solve_h48_maketasks(
     solve_h48_task_t [static STARTING_CUBES], int *);
 STATIC void *solve_h48_runthread(void *);
 STATIC int64_t solve_h48_dfs(dfsarg_solve_h48_t *);
-STATIC int64_t solve_h48(cube_t, int8_t, int8_t, uint64_t, uint64_t,
+STATIC int64_t solve_h48(cube_t, int8_t, int8_t, uint64_t, int, uint64_t,
     const void *, uint64_t, char *, long long [static NISSY_SIZE_SOLVE_STATS]);
 
 STATIC int64_t
@@ -316,7 +317,7 @@ solve_h48_runthread(void *arg)
         dfsarg = (dfsarg_solve_h48_t *)arg;
         cube = dfsarg->start_cube;
 
-        for (i = dfsarg->thread_id; i < dfsarg->ntasks; i += THREADS) {
+        for (i = dfsarg->thread_id; i < dfsarg->ntasks; i += dfsarg->threads) {
                 task = dfsarg->tasks[i];
                 memcpy(dfsarg->moves, task.moves, STARTING_MOVES);
                 dfsarg->cube = cube;
@@ -407,6 +408,7 @@ solve_h48(
         int8_t minmoves,
         int8_t maxmoves,
         uint64_t maxsolutions,
+        int threads,
         uint64_t data_size,
         const void *data,
         uint64_t solutions_size,
@@ -461,7 +463,7 @@ solve_h48(
         fallback2 = h48data + offset;
 
         symmask = symmetry_mask(cube);
-        for (i = 0; i < THREADS; i++) {
+        for (i = 0; i < threads; i++) {
                 arg[i] = (dfsarg_solve_h48_t) {
                         .start_cube = cube,
                         .cube = cube,
@@ -481,6 +483,7 @@ solve_h48(
                         .nodes_visited = 0,
                         .table_fallbacks = 0,
                         .table_lookups = 0,
+                        .threads = threads,
                         .thread_id = i,
                         .solutions_mutex = &solutions_mutex,
                 };
@@ -505,7 +508,7 @@ solve_h48(
         if (*arg[0].nsols >= (int64_t)maxsolutions)
                 goto solve_h48_done;
 
-        for (i = 0; i < THREADS; i++) {
+        for (i = 0; i < threads; i++) {
                 arg[i].ntasks = ntasks;
                 arg[i].tasks = tasks;
         }
@@ -520,12 +523,12 @@ solve_h48(
                 if (d >= 10)
                         LOG("Found %" PRId64 " solutions, searching at depth %"
                             PRId8 "\n", nsols, d);
-                for (i = 0; i < THREADS; i++) {
+                for (i = 0; i < threads; i++) {
                         arg[i].depth = d;
                         pthread_create(
                             &thread[i], NULL, solve_h48_runthread, &arg[i]);
                 }
-                for (i = 0; i < THREADS; i++)
+                for (i = 0; i < threads; i++)
                         pthread_join(thread[i], NULL);
         }
 
@@ -534,7 +537,7 @@ solve_h48_done:
                 goto solve_h48_error_solutions_buffer;
 
         nodes_visited = table_lookups = table_fallbacks = 0;
-        for (i = 0; i < THREADS; i++) {
+        for (i = 0; i < threads; i++) {
                 nodes_visited += arg[i].nodes_visited;
                 table_fallbacks += arg[i].table_fallbacks;
                 table_lookups += arg[i].table_lookups;
diff --git a/tools/300_solve_small/solve_small.c b/tools/300_solve_small/solve_small.c
index 09ca85a..073de89 100644
--- a/tools/300_solve_small/solve_small.c
+++ b/tools/300_solve_small/solve_small.c
@@ -37,7 +37,7 @@ void run(void) {
                         continue;
                 }
                 n = nissy_solve(cube, solver, NISSY_NISSFLAG_NORMAL,
-                    0, 20, 1, -1, size, buf, SOL_BUFFER_LEN, sol, stats);
+                    0, 20, 1, -1, 0, size, buf, SOL_BUFFER_LEN, sol, stats);
                 if (n == 0)
                         printf("No solution found\n");
                 else
diff --git a/tools/301_solve_file/solve_file.c b/tools/301_solve_file/solve_file.c
index aa45df0..fe41bb7 100644
--- a/tools/301_solve_file/solve_file.c
+++ b/tools/301_solve_file/solve_file.c
@@ -24,7 +24,7 @@ void run(void) {
                         continue;
                 }
                 nsols = nissy_solve(cube, solver, NISSY_NISSFLAG_NORMAL,
-                    0, 20, 1, -1, size, buf, SOL_BUFFER_LEN, sol, stats);
+                    0, 20, 1, -1, 0, size, buf, SOL_BUFFER_LEN, sol, stats);
                 if (nsols == 0)
                         printf("No solution found\n");
                 else
diff --git a/tools/302_solve_multisol/solve_multisol.c b/tools/302_solve_multisol/solve_multisol.c
index 739ccbd..a03c2a0 100644
--- a/tools/302_solve_multisol/solve_multisol.c
+++ b/tools/302_solve_multisol/solve_multisol.c
@@ -30,7 +30,7 @@ void run(void) {
                         continue;
                 }
                 n = nissy_solve(cube, solver, NISSY_NISSFLAG_NORMAL,
-                    0, 20, nsol, -1, size, buf, SOL_BUFFER_LEN, sol, stats);
+                    0, 20, nsol, -1, 0, size, buf, SOL_BUFFER_LEN, sol, stats);
                 if (n == 0)
                         printf("No solution found\n");
                 else