Merge remote-tracking branch 'upstream/master'

Merge upstream

33 files changed, 538 insertions, 347 deletions

diff --git a/.gitignore b/.gitignore
index bff1f6a..2e79f0a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -14,6 +14,7 @@ test/run
 test/run.DSYM
 tools/.DS_Store
 run.DSYM
+run.core
 test/last.*
 tools/results
 .vscode
diff --git a/README.md b/README.md
index 09b5881..9ecd744 100644
--- a/README.md
+++ b/README.md
@@ -61,7 +61,7 @@ The results of the last test case run is saved in test/last.out (standard
 output, the results compared with the .out files) and test/last.err
 (standard error).
 
-Tests are always run in "debug mode": this means that optimizations are
+Tests are always run in debug mode: this means that optimizations are
 disabled and some extra logging is enabled.
 
 See the test folder and test/test.sh for details.
@@ -70,7 +70,7 @@ See the test folder and test/test.sh for details.
 
 In the tools folder there are some small programs that test various
 functionality of the H48 library. They work similarly to test, but they
-are not run in debug mode.
+are not run in debug mode by default.
 
 To run a tool you must select it with the environment variable `TOOL`.
 For example the command:
@@ -79,14 +79,26 @@ For example the command:
 TOOL=stats make tool
 ```
 
-Will run the stats_tables_h48 tool. Like for tests, the value of the
-`TOOL` variable can be any regular expression matching the name of the
-tool. Unlike tests, one and only one tool will be selected for each run.
+Will run the stats_tables_h48 tool.
+
+To pass some arguments to a tool, use the `TOOLARGS` variable:
+
+```
+TOOL=gendata TOOLARGS="h48 0;2;20" make tool
+```
+
+Like for tests, the value of the `TOOL` variable can be any regular
+expression matching the name of the tool. Unlike tests, one and
+only one tool will be selected for each run.  The content of the
+`TOOLARGS` variable is used directly as command line arguments for
+the chosen tool.
 
 Each tool run is automatically timed, so these tools can be used as
 benchmark.  The output as well as the time of the run are saved to a
 file in the tools/results folder.
 
+To build and run a tool in debug mode, use `make debugtool`.
+
 ## Running commands manually
 
 This project also includes a rudimentary shell that can be used to run
diff --git a/configure.sh b/configure.sh
index e61a163..2b2f40b 100755
--- a/configure.sh
+++ b/configure.sh
@@ -22,10 +22,10 @@
 # SANITIZE="option1,option2,..."
 # Add the options "-fsanitize=option1", "-fsanitize=option2", ... to the
 # compilation command when compiling in debug mode.
-# By default, "-fsanitize=address" and "-fsanitize=undefined" will be used,
-# if available. If this variable is set, the default is overridden.
-# No check is performed on the given sanitizers, make sure that the ones you
-# choose are available on your system and compatible with each other.
+# By default, "-fsanitize=address" and "-fsanitize=undefined" will be used.
+# If this variable is set, the default is overridden. No check is performed
+# on the availability of any sanitizer used, make sure the ones you use are
+# available on your system.
 #
 # Examples
 #
@@ -39,10 +39,6 @@ greparch() {
         $CC -march=native -dM -E - </dev/null 2>/dev/null | grep "$1"
 }
 
-grepsan() {
-        $CC -fsanitize="$1" -dM -E -x c - </dev/null 2>/dev/null | grep "SANITIZE"
-}
-
 detectthreads() {
         echo 16 # TODO: choose based on system
 }
@@ -100,10 +96,7 @@ if [ -n "$SANITIZE" ]; then
                 SAN="$SAN -fsanitize=$san"
         done
 else
-        # No sanitizer specified, use "address" and "undefined" if present
-        [ -n "$(grepsan address)" ] && ADDR="-fsanitize=address"
-        [ -n "$(grepsan undefined)" ] && UNDEF="-fsanitize=undefined"
-        SAN="$ADDR $UNDEF"
+        SAN="-fsanitize=address -fsanitize=undefined"
 fi
 LIBS="-lpthread"
 
diff --git a/src/nissy.c b/src/nissy.c
index a2da73d..44efb83 100644
--- a/src/nissy.c
+++ b/src/nissy.c
@@ -12,8 +12,11 @@
 
 #include "nissy.h"
 
-STATIC int parse_h48_options(const char *, uint8_t *, uint8_t *, uint8_t *);
+int parse_h48_options(const char *, uint8_t *, uint8_t *, uint8_t *);
 STATIC int64_t write_result(cube_t, char [static 22]);
+STATIC bool distribution_equal(const uint64_t [static INFO_DISTRIBUTION_LEN],
+    const uint64_t [static INFO_DISTRIBUTION_LEN], uint8_t);
+STATIC bool checkdata(const void *, const tableinfo_t *);
 
 /* TODO: add option to get DR, maybe C-only, E-only, eo... */
 #define GETCUBE_OPTIONS(S, F) { .option = S, .fix = F }
@@ -25,7 +28,7 @@ struct {
         GETCUBE_OPTIONS(NULL, NULL)
 };
 
-STATIC int
+int
 parse_h48_options(const char *buf, uint8_t *h, uint8_t *k, uint8_t *maxdepth)
 {
         bool h_valid, k_valid, maxdepth_valid;
@@ -63,6 +66,52 @@ parse_h48_options_error:
         return -1;
 }
 
+STATIC bool
+checkdata(const void *buf, const tableinfo_t *info)
+{
+        uint64_t distr[INFO_DISTRIBUTION_LEN];
+
+        if (!strncmp(info->solver, "cocsep", 6)) {
+                getdistribution_cocsep(
+                    (uint32_t *)((char *)buf + INFOSIZE), distr);
+        } else if (!strncmp(info->solver, "h48", 3)) {
+                getdistribution_h48((uint8_t *)buf + INFOSIZE, distr,
+                    info->h48h, info->bits);
+        } else {
+                LOG("checkdata: unknown solver %s\n", info->solver);
+                return false;
+        }
+
+        return distribution_equal(info->distribution, distr, info->maxvalue);
+}
+
+STATIC bool
+distribution_equal(
+        const uint64_t expected[static INFO_DISTRIBUTION_LEN],
+        const uint64_t actual[static INFO_DISTRIBUTION_LEN],
+        uint8_t maxvalue
+)
+{
+        int wrong;
+        uint8_t i;
+
+        for (i = 0, wrong = 0; i <= MAX(maxvalue, 20); i++) {
+                if (expected[i] != actual[i]) {
+                        wrong++;
+                        LOG("Value %" PRIu8 ": expected %" PRIu64 ", found %"
+                            PRIu64 "\n", i, expected[i], actual[i]);
+                }
+        }
+
+        if (wrong > 0) {
+                LOG("checkdata: %d wrong values\n", wrong);
+        } else {
+                LOG("checkdata: table is consistent with info\n");
+        }
+
+        return wrong > 0;
+}
+
 STATIC int64_t
 write_result(cube_t cube, char result[static 22])
 {
@@ -276,6 +325,26 @@ nissy_gendata(
 }
 
 int64_t
+nissy_checkdata(
+        const char *solver,
+        const char *options,
+        const void *data
+)
+{
+        char *buf;
+        tableinfo_t info;
+
+        for (buf = (char *)data; readtableinfo(buf, &info); buf += info.next) {
+                if (!checkdata(buf, &info))
+                        return 1;
+                if (info.next == 0)
+                        break;
+        }
+
+        return 0;
+}
+
+int64_t
 nissy_solve(
         const char cube[static 22],
         const char *solver, 
diff --git a/src/nissy.h b/src/nissy.h
index 336130c..0545556 100644
--- a/src/nissy.h
+++ b/src/nissy.h
@@ -86,6 +86,19 @@ int64_t nissy_gendata(
         void *generated_data
 );
 
+/* Temporarily added to test h48 intermediate tables */
+int64_t nissy_derivedata(
+        const char *options,
+        const void *fulltable,
+        void *generated_data
+);
+
+int64_t nissy_checkdata(
+        const char *solver,
+        const char *options,
+        const void *data
+);
+
 /* Print information on a data table via the provided callback writer */
 int64_t nissy_datainfo(
         const void *table,
diff --git a/src/solvers/h48/gendata_cocsep.h b/src/solvers/h48/gendata_cocsep.h
index 2189145..262793b 100644
--- a/src/solvers/h48/gendata_cocsep.h
+++ b/src/solvers/h48/gendata_cocsep.h
@@ -25,6 +25,7 @@ STATIC_INLINE void set_visited(uint8_t *, int64_t);
 
 STATIC size_t gendata_cocsep(void *, uint64_t *, cube_t *);
 STATIC uint32_t gendata_cocsep_dfs(cocsep_dfs_arg_t *);
+STATIC void getdistribution_cocsep(const uint32_t *, uint64_t [static 21]);
 
 STATIC_INLINE int8_t get_h48_cdata(cube_t, uint32_t *, uint32_t *);
 
@@ -157,6 +158,17 @@ gendata_cocsep_dfs(cocsep_dfs_arg_t *arg)
         return cc;
 }
 
+STATIC void
+getdistribution_cocsep(const uint32_t *table, uint64_t distr[static 21])
+{
+        size_t i;
+
+        memset(distr, 0, 21 * sizeof(uint64_t));
+
+        for (i = 0; i < COCSEP_TABLESIZE; i++)
+                distr[CBOUND(table[i])]++;
+}
+
 STATIC_INLINE bool
 get_visited(const uint8_t *a, int64_t i)
 {
diff --git a/src/solvers/h48/gendata_h48.h b/src/solvers/h48/gendata_h48.h
index 3445570..75b7abf 100644
--- a/src/solvers/h48/gendata_h48.h
+++ b/src/solvers/h48/gendata_h48.h
@@ -103,14 +103,19 @@ STATIC_INLINE bool gendata_h48k2_dfs_stop(cube_t, int8_t, h48k2_dfs_arg_t *);
 STATIC size_t gendata_h48k2_realcoord(gendata_h48_arg_t *);
 STATIC void gendata_h48k2_dfs(h48k2_dfs_arg_t *arg);
 STATIC void * gendata_h48k2_runthread(void *);
-STATIC tableinfo_t makeinfo_h48k2(gendata_h48_arg_t *, uint8_t);
+STATIC tableinfo_t makeinfo_h48k2(gendata_h48_arg_t *);
+STATIC void getdistribution_h48(const uint8_t *,
+    uint64_t [static INFO_DISTRIBUTION_LEN], uint8_t, uint8_t);
 
 STATIC uint32_t *get_cocsepdata_ptr(const void *);
 STATIC uint8_t *get_h48data_ptr(const void *);
 
 STATIC_INLINE uint8_t get_h48_pval(const uint8_t *, int64_t, uint8_t);
 STATIC_INLINE void set_h48_pval(uint8_t *, int64_t, uint8_t, uint8_t);
-STATIC_INLINE uint8_t get_h48_bound(cube_t, uint32_t, uint8_t, uint8_t, uint8_t *);
+STATIC_INLINE uint8_t get_h48_bound(
+    cube_t, uint32_t, uint8_t, uint8_t, uint8_t *);
+
+size_t gendata_h48_derive(uint8_t, const void *, void *);
 
 STATIC uint64_t
 gendata_h48short(gendata_h48short_arg_t *arg)
@@ -387,7 +392,7 @@ gendata_h48k2(gendata_h48_arg_t *arg)
                 [11] = 10
         };
 
-        uint8_t t, selectedbase, *table;
+        uint8_t t, *table;
         int64_t j;
         uint64_t i, ii, inext, count;
         h48map_t shortcubes;
@@ -414,8 +419,9 @@ gendata_h48k2(gendata_h48_arg_t *arg)
         };
         gendata_h48short(&shortarg);
 
-        selectedbase = arg->base < 20 ? arg->base : base[arg->h];
-        arg->info = makeinfo_h48k2(arg, selectedbase);
+        if (arg->base >= 20)
+                arg->base = base[arg->h];
+        arg->info = makeinfo_h48k2(arg);
 
         inext = count = 0;
         pthread_mutex_init(&shortcubes_mutex, NULL);
@@ -425,7 +431,7 @@ gendata_h48k2(gendata_h48_arg_t *arg)
                 dfsarg[i] = (h48k2_dfs_arg_t){
                         .h = arg->h,
                         .k = arg->k,
-                        .base = selectedbase,
+                        .base = arg->base,
                         .shortdepth = shortdepth,
                         .cocsepdata = arg->cocsepdata,
                         .table = table,
@@ -603,14 +609,17 @@ STATIC_INLINE bool
 gendata_h48k2_dfs_stop(cube_t cube, int8_t depth, h48k2_dfs_arg_t *arg)
 {
         uint64_t val;
-        int64_t coord;
+        int64_t coord, mutex;
         int8_t oldval;
 
         if (arg->h == 0 || arg->h == 11) {
                 /* We are in the "real coordinate" case, we can stop
                    if this coordinate has already been visited */
                 coord = coord_h48(cube, arg->cocsepdata, arg->h);
+                mutex = H48_INDEX(coord, arg->k) % CHUNKS;
+                pthread_mutex_lock(arg->table_mutex[mutex]);
                 oldval = get_h48_pval(arg->table, coord, arg->k);
+                pthread_mutex_unlock(arg->table_mutex[mutex]);
                 return oldval <= depth;
         } else {
                 /* With 0 < k < 11 we do not have a "real coordinate".
@@ -637,7 +646,7 @@ gendata_h48k2_realcoord_runthread(void *arg)
 }
 
 STATIC tableinfo_t
-makeinfo_h48k2(gendata_h48_arg_t *arg, uint8_t base)
+makeinfo_h48k2(gendata_h48_arg_t *arg)
 {
         tableinfo_t info;
 
@@ -651,7 +660,7 @@ makeinfo_h48k2(gendata_h48_arg_t *arg, uint8_t base)
                 .classes = 0,
                 .h48h = arg->h,
                 .bits = 2,
-                .base = base,
+                .base = arg->base,
                 .maxvalue = 3,
                 .next = 0,
         };
@@ -662,6 +671,25 @@ makeinfo_h48k2(gendata_h48_arg_t *arg, uint8_t base)
         return info;
 }
 
+STATIC void
+getdistribution_h48(
+        const uint8_t *table,
+        uint64_t distr[static INFO_DISTRIBUTION_LEN],
+        uint8_t h,
+        uint8_t k
+) {
+        uint8_t val;
+        int64_t i, h48max;
+
+        memset(distr, 0, INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
+
+        h48max = H48_COORDMAX(h);
+        for (i = 0; i < h48max; i++) {
+                val = get_h48_pval(table, i, k);
+                distr[val]++;
+        }
+}
+
 STATIC uint32_t *
 get_cocsepdata_ptr(const void *data)
 {
@@ -695,3 +723,77 @@ get_h48_bound(cube_t cube, uint32_t cdata, uint8_t h, uint8_t k, uint8_t *table)
         coord = coord_h48_edges(cube, COCLASS(cdata), TTREP(cdata), h);
         return get_h48_pval(table, coord, k);
 }
+
+size_t
+gendata_h48_derive(uint8_t h, const void *fulltable, void *buf)
+{
+        size_t cocsepsize, h48size;
+        uint8_t val_full, val_derive, *h48full, *h48derive;
+        int64_t i, j, h48max;
+        gendata_h48_arg_t arg;
+        tableinfo_t cocsepinfo, fulltableinfo;
+
+        /* Initializing values in case of error */
+        /* TODO cleanup this */
+        fulltableinfo.bits = 2;
+        fulltableinfo.base = 8;
+
+        readtableinfo_n(fulltable, 2, &fulltableinfo);
+        arg.h = h;
+        arg.k = fulltableinfo.bits;
+        arg.maxdepth = 20;
+        arg.buf = buf;
+        arg.cocsepdata = (uint32_t *)((char *)buf + INFOSIZE);
+        arg.base = fulltableinfo.base;
+        arg.info = makeinfo_h48k2(&arg);
+
+        /* Technically this step is redundant, except that we
+           need selfsim and crep */
+        cocsepsize = gendata_cocsep(buf, arg.selfsim, arg.crep);
+        arg.h48buf = (uint8_t *)buf + cocsepsize;
+        h48size = H48_TABLESIZE(h, arg.k) + INFOSIZE;
+
+        if (buf == NULL)
+                goto gendata_h48_derive_return_size;
+
+        if (!readtableinfo(buf, &cocsepinfo)) {
+                LOG("gendata_h48: could not read info for cocsep table\n");
+                goto gendata_h48_derive_error;
+        }
+
+        cocsepinfo.next = cocsepsize;
+        if (!writetableinfo(&cocsepinfo, buf)) {
+                LOG("gendata_h48_derive: could not write info for cocsep table"
+                    " with updated 'next' value\n");
+                goto gendata_h48_derive_error;
+        }
+
+        h48full = (uint8_t *)fulltable + cocsepsize + INFOSIZE;
+        h48derive = (uint8_t *)arg.h48buf + INFOSIZE;
+        memset(h48derive, 0xFF, H48_TABLESIZE(h, arg.k));
+        memset(arg.info.distribution, 0,
+            INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
+
+        h48max = H48_COORDMAX(fulltableinfo.h48h);
+        for (i = 0; i < h48max; i++) {
+                if (i % INT64_C(1000000000) == 0 && i > 0)
+                        LOG("Processing %" PRId64 "th coordinate\n", i);
+                j = i >> (int64_t)(fulltableinfo.h48h - h);
+                val_full = get_h48_pval(h48full, i, arg.k);
+                val_derive = get_h48_pval(h48derive, j, arg.k);
+                set_h48_pval(h48derive, j, arg.k, MIN(val_full, val_derive));
+        }
+
+        getdistribution_h48(h48derive, arg.info.distribution, h, arg.k);
+
+        if (!writetableinfo(&arg.info, arg.h48buf)) {
+                LOG("gendata_h48_derive: could not write info for table\n");
+                goto gendata_h48_derive_error;
+        }
+
+gendata_h48_derive_return_size:
+        return cocsepsize + h48size;
+
+gendata_h48_derive_error:
+        return 0;
+}
diff --git a/src/solvers/tables.h b/src/solvers/tables.h
index bad3b2c..a668988 100644
--- a/src/solvers/tables.h
+++ b/src/solvers/tables.h
@@ -7,34 +7,34 @@
 #define TABLETYPE_PRUNING        0
 #define TABLETYPE_SPECIAL        1
 
-#define INFO_OFFSET_SOLVER       0
-#define INFO_OFFSET_TYPE         INFO_SOLVER_STRLEN
+#define INFO_OFFSET_DISTRIBUTION 0
+#define INFO_OFFSET_TYPE         (INFO_DISTRIBUTION_LEN * sizeof(uint64_t))
 #define INFO_OFFSET_INFOSIZE     (INFO_OFFSET_TYPE + sizeof(uint64_t))
 #define INFO_OFFSET_FULLSIZE     (INFO_OFFSET_INFOSIZE + sizeof(uint64_t))
 #define INFO_OFFSET_HASH         (INFO_OFFSET_FULLSIZE + sizeof(uint64_t))
 #define INFO_OFFSET_ENTRIES      (INFO_OFFSET_HASH + sizeof(uint64_t))
 #define INFO_OFFSET_CLASSES      (INFO_OFFSET_ENTRIES + sizeof(uint64_t))
-#define INFO_OFFSET_H48H         (INFO_OFFSET_CLASSES + sizeof(uint64_t))
+#define INFO_OFFSET_NEXT         (INFO_OFFSET_CLASSES + sizeof(uint64_t))
+#define INFO_OFFSET_SOLVER       (INFO_OFFSET_NEXT + sizeof(uint64_t))
+#define INFO_OFFSET_H48H         (INFO_OFFSET_SOLVER + INFO_SOLVER_STRLEN)
 #define INFO_OFFSET_BITS         (INFO_OFFSET_H48H + sizeof(uint8_t))
 #define INFO_OFFSET_BASE         (INFO_OFFSET_BITS + sizeof(uint8_t))
 #define INFO_OFFSET_MAXVALUE     (INFO_OFFSET_BASE + sizeof(uint8_t))
-#define INFO_OFFSET_NEXT         (INFO_OFFSET_MAXVALUE + sizeof(uint8_t))
-#define INFO_OFFSET_DISTRIBUTION (INFO_OFFSET_NEXT + sizeof(uint64_t))
 
 typedef struct {
-        char solver[INFO_SOLVER_STRLEN];
+        uint64_t distribution[INFO_DISTRIBUTION_LEN];
         uint64_t type;
         uint64_t infosize;
         uint64_t fullsize;
         uint64_t hash;
         uint64_t entries;
         uint64_t classes; /* Used only by cocsepdata, for now */
+        uint64_t next;
+        char solver[INFO_SOLVER_STRLEN];
         uint8_t h48h; /* Specific to H48 tables */
         uint8_t bits;
         uint8_t base;
         uint8_t maxvalue;
-        uint64_t next;
-        uint64_t distribution[INFO_DISTRIBUTION_LEN];
 } tableinfo_t;
 
 STATIC bool readtableinfo(const void *, tableinfo_t *);
@@ -54,21 +54,24 @@ readtableinfo(const void *buf, tableinfo_t *info)
                 return false;
         }
 
-        memcpy(info->solver, OFFSET(buf, INFO_OFFSET_SOLVER),
-            INFO_SOLVER_STRLEN);
+        memcpy(info->distribution, OFFSET(buf, INFO_OFFSET_DISTRIBUTION),
+            INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
+
         info->type = *(const uint64_t *)OFFSET(buf, INFO_OFFSET_TYPE);
         info->infosize = *(const uint64_t *)OFFSET(buf, INFO_OFFSET_INFOSIZE);
         info->fullsize = *(const uint64_t *)OFFSET(buf, INFO_OFFSET_FULLSIZE);
         info->hash = *(const uint64_t *)OFFSET(buf, INFO_OFFSET_HASH);
         info->entries = *(const uint64_t *)OFFSET(buf, INFO_OFFSET_ENTRIES);
         info->classes = *(const uint64_t *)OFFSET(buf, INFO_OFFSET_CLASSES);
+        info->next = *(const uint64_t* )OFFSET(buf, INFO_OFFSET_NEXT);
+
+        memcpy(info->solver, OFFSET(buf, INFO_OFFSET_SOLVER),
+            INFO_SOLVER_STRLEN);
+
         info->h48h = *OFFSET(buf, INFO_OFFSET_H48H);
         info->bits = *OFFSET(buf, INFO_OFFSET_BITS);
         info->base = *OFFSET(buf, INFO_OFFSET_BASE);
         info->maxvalue = *OFFSET(buf, INFO_OFFSET_MAXVALUE);
-        info->next = *(const uint64_t* )OFFSET(buf, INFO_OFFSET_NEXT);
-        memcpy(info->distribution, OFFSET(buf, INFO_OFFSET_DISTRIBUTION),
-            INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
 
         return true;
 }
@@ -98,6 +101,17 @@ writetableinfo(const tableinfo_t *info, void *buf)
                 return false;
         }
 
+        memcpy(OFFSET(buf, INFO_OFFSET_DISTRIBUTION), info->distribution,
+            INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
+
+        *(uint64_t *)OFFSET(buf, INFO_OFFSET_TYPE) = info->type;
+        *(uint64_t *)OFFSET(buf, INFO_OFFSET_INFOSIZE) = info->infosize;
+        *(uint64_t *)OFFSET(buf, INFO_OFFSET_FULLSIZE) = info->fullsize;
+        *(uint64_t *)OFFSET(buf, INFO_OFFSET_HASH) = info->hash;
+        *(uint64_t *)OFFSET(buf, INFO_OFFSET_ENTRIES) = info->entries;
+        *(uint64_t *)OFFSET(buf, INFO_OFFSET_CLASSES) = info->classes;
+        *(uint64_t *)OFFSET(buf, INFO_OFFSET_NEXT) = info->next;
+
         memcpy(OFFSET(buf, INFO_OFFSET_SOLVER), info->solver,
             INFO_SOLVER_STRLEN);
 
@@ -106,20 +120,10 @@ writetableinfo(const tableinfo_t *info, void *buf)
                 if (*OFFSET(buf, i) == 0)
                         *OFFSET(buf, i) = 0;
 
-        *(uint64_t *)OFFSET(buf, INFO_OFFSET_TYPE) = info->type;
-        *(uint64_t *)OFFSET(buf, INFO_OFFSET_INFOSIZE) = info->infosize;
-        *(uint64_t *)OFFSET(buf, INFO_OFFSET_FULLSIZE) = info->fullsize;
-        *(uint64_t *)OFFSET(buf, INFO_OFFSET_HASH) = info->hash;
-        *(uint64_t *)OFFSET(buf, INFO_OFFSET_ENTRIES) = info->entries;
-        *(uint64_t *)OFFSET(buf, INFO_OFFSET_CLASSES) = info->classes;
         *OFFSET(buf, INFO_OFFSET_H48H) = info->h48h;
         *OFFSET(buf, INFO_OFFSET_BITS) = info->bits;
         *OFFSET(buf, INFO_OFFSET_BASE) = info->base;
         *OFFSET(buf, INFO_OFFSET_MAXVALUE) = info->maxvalue;
-        *(uint64_t *)OFFSET(buf, INFO_OFFSET_NEXT) = info->next;
-
-        memcpy(OFFSET(buf, INFO_OFFSET_DISTRIBUTION), info->distribution,
-            INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
 
         return true;
 }
diff --git a/test/090_tables_readwrite/tables_readwrite_tests.c b/test/090_tables_readwrite/tables_readwrite_tests.c
index e1c2015..73c4e21 100644
--- a/test/090_tables_readwrite/tables_readwrite_tests.c
+++ b/test/090_tables_readwrite/tables_readwrite_tests.c
@@ -5,19 +5,19 @@
 #define INFO_DISTRIBUTION_LEN    21
 
 typedef struct {
-        char solver[INFO_SOLVER_STRLEN];
+        uint64_t distribution[INFO_DISTRIBUTION_LEN];
         uint64_t type;
         uint64_t infosize;
         uint64_t fullsize;
         uint64_t hash;
         uint64_t entries;
         uint64_t classes;
+        uint64_t next;
+        char solver[INFO_SOLVER_STRLEN];
         uint8_t h48h;
         uint8_t bits;
         uint8_t base;
         uint8_t maxvalue;
-        uint64_t next;
-        uint64_t distribution[INFO_DISTRIBUTION_LEN];
 } tableinfo_t;
 
 bool readtableinfo(const void *, tableinfo_t *);
diff --git a/test/100_gendata_cocsep/gendata_cocsep_tests.c b/test/100_gendata_cocsep/gendata_cocsep_tests.c
index 7630a71..62f52fb 100644
--- a/test/100_gendata_cocsep/gendata_cocsep_tests.c
+++ b/test/100_gendata_cocsep/gendata_cocsep_tests.c
@@ -6,19 +6,19 @@
 #define COCSEP_CLASSES           3393
 
 typedef struct {
-        char solver[INFO_SOLVER_STRLEN];
+        uint64_t distribution[INFO_DISTRIBUTION_LEN];
         uint64_t type;
         uint64_t infosize;
         uint64_t fullsize;
         uint64_t hash;
         uint64_t entries;
         uint64_t classes; /* Used only by cocsepdata, for now */
+        uint64_t next;
+        char solver[INFO_SOLVER_STRLEN];
         uint8_t h48h;
         uint8_t bits;
         uint8_t base;
         uint8_t maxvalue;
-        uint64_t next;
-        uint64_t distribution[INFO_DISTRIBUTION_LEN];
 } tableinfo_t;
 
 size_t gendata_cocsep(void *, uint64_t *, cube_t *);
diff --git a/test/120_gendata_h48h0k4/gendata_h48h0k4_tests.c b/test/120_gendata_h48h0k4/gendata_h48h0k4_tests.c
index 41ab10a..7c5b441 100644
--- a/test/120_gendata_h48h0k4/gendata_h48h0k4_tests.c
+++ b/test/120_gendata_h48h0k4/gendata_h48h0k4_tests.c
@@ -6,24 +6,25 @@
 #define INFO_DISTRIBUTION_LEN 21
 
 typedef struct {
-        char solver[INFO_SOLVER_STRLEN];
+        uint64_t distribution[INFO_DISTRIBUTION_LEN];
         uint64_t type;
         uint64_t infosize;
         uint64_t fullsize;
         uint64_t hash;
         uint64_t entries;
         uint64_t classes; /* Used only by cocsepdata, for now */
+        uint64_t next;
+        char solver[INFO_SOLVER_STRLEN];
         uint8_t h48h;
         uint8_t bits;
         uint8_t base;
         uint8_t maxvalue;
-        uint64_t next;
-        uint64_t distribution[INFO_DISTRIBUTION_LEN];
 } tableinfo_t;
 
 typedef struct {
         uint8_t h;
         uint8_t k;
+        uint8_t base;
         uint8_t maxdepth;
         tableinfo_t info;
         void *buf;
diff --git a/tools/0002_gendata_h48h0k2/gendata_h48h0k2.c b/tools/0002_gendata_h48h0k2/gendata_h48h0k2.c
deleted file mode 100644
index 14f99ee..0000000
--- a/tools/0002_gendata_h48h0k2/gendata_h48h0k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 5473562,
-        [1] = 34776317,
-        [2] = 68566704,
-        [3] = 8750867,
-};
-
-void run(void) {
-        gendata_run("h48", "0;2;20", "tables/h48h0k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 0, k = 2");
-
-        return 0;
-}
diff --git a/tools/0004_gendata_h48h0k4/gendata_h48h0k4.c b/tools/0004_gendata_h48h0k4/gendata_h48h0k4.c
deleted file mode 100644
index ff34bb9..0000000
--- a/tools/0004_gendata_h48h0k4/gendata_h48h0k4.c
+++ /dev/null
@@ -1,29 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        [0] = 1,
-        [1] = 1,
-        [2] = 4,
-        [3] = 34,
-        [4] = 331,
-        [5] = 3612,
-        [6] = 41605,
-        [7] = 474128,
-        [8] = 4953846,
-        [9] = 34776317,
-        [10] = 68566704,
-        [11] = 8749194,
-        [12] = 1673,
-};
-
-void run(void) {
-        gendata_run("h48", "0;4;20", "tables/h48h0k4", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 0, k = 4");
-
-        return 0;
-}
diff --git a/tools/000_gendata/gendata.c b/tools/000_gendata/gendata.c
new file mode 100644
index 0000000..90166dd
--- /dev/null
+++ b/tools/000_gendata/gendata.c
@@ -0,0 +1,55 @@
+#include "../tool.h"
+#include "../expected_distributions.h"
+
+char *solver, *options;
+uint64_t *expected;
+
+static void
+run(void) {
+        int64_t size;
+        char *buf, filename[1024];
+        
+        getfilename(solver, options, filename);
+        size = generatetable(solver, options, &buf);
+        switch (size) {
+        case -1:
+                return;
+        case -2:
+                goto gendata_run_finish;
+        default:
+                nissy_datainfo(buf, write_stdout);
+                printf("\n");
+                printf("Succesfully generated %" PRId64 " bytes. "
+                       "See above for details on the tables.\n", size);
+
+                writetable(buf, size, filename);
+                break;
+        }
+
+gendata_run_finish:
+        free(buf);
+}
+
+int main(int argc, char **argv) {
+        uint8_t h, k;
+        char description[256];
+
+        if (argc < 3) {
+                fprintf(stderr, "Error: not enough arguments. "
+                    "A solver and its options must be given.\n");
+                return 1;
+        }
+
+        solver = argv[1];
+        options = argv[2];
+        parse_h48_options(options, &h, &k, NULL);
+        expected = expected_h48[h][k];
+        sprintf(description, "benchmark gendata_h48 h = %" PRIu8
+            ", k = %" PRIu8 "", h, k);
+
+        nissy_setlogger(log_stderr);
+
+        timerun(run, description);
+
+        return 0;
+}
diff --git a/tools/0012_gendata_h48h1k2/gendata_h48h1k2.c b/tools/0012_gendata_h48h1k2/gendata_h48h1k2.c
deleted file mode 100644
index 0ebdcaa..0000000
--- a/tools/0012_gendata_h48h1k2/gendata_h48h1k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "1;2;20", "tables/h48h1k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 1, k = 2");
-
-        return 0;
-}
diff --git a/tools/001_derive_h48/derive_h48.c b/tools/001_derive_h48/derive_h48.c
new file mode 100644
index 0000000..3c7f8cc
--- /dev/null
+++ b/tools/001_derive_h48/derive_h48.c
@@ -0,0 +1,33 @@
+#include "../tool.h"
+
+char *opts_large, *opts_small, *filename_large, *filename_small;
+
+void run(void) {
+        derivedata_run(opts_large, opts_small, filename_large, filename_small);
+}
+
+int main(int argc, char **argv) {
+        char description[256];
+
+        if (argc < 5) {
+                fprintf(stderr,
+                    "Error: not enough arguments. Required:\n"
+                    "1. Options for large table\n"
+                    "2. Options for derived table\n"
+                    "3. Filename containing large table\n"
+                    "4. Filename for saving derived table\n");
+                return 1;
+        }
+
+        opts_large = argv[1];
+        opts_small = argv[2];
+        filename_large = argv[3];
+        filename_small = argv[4];
+        sprintf(description, "deriving %s from %s\n", opts_small, opts_large);
+
+        nissy_setlogger(log_stderr);
+
+        timerun(run, description);
+
+        return 0;
+}
diff --git a/tools/0022_gendata_h48h2k2/gendata_h48h2k2.c b/tools/0022_gendata_h48h2k2/gendata_h48h2k2.c
deleted file mode 100644
index f437e98..0000000
--- a/tools/0022_gendata_h48h2k2/gendata_h48h2k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "2;2;20", "tables/h48h2k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 2, k = 2");
-
-        return 0;
-}
diff --git a/tools/0032_gendata_h48h3k2/gendata_h48h3k2.c b/tools/0032_gendata_h48h3k2/gendata_h48h3k2.c
deleted file mode 100644
index 2e0eab5..0000000
--- a/tools/0032_gendata_h48h3k2/gendata_h48h3k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "3;2;20", "tables/h48h3k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 3, k = 2");
-
-        return 0;
-}
diff --git a/tools/0042_gendata_h48h4k2/gendata_h48h4k2.c b/tools/0042_gendata_h48h4k2/gendata_h48h4k2.c
deleted file mode 100644
index 868c360..0000000
--- a/tools/0042_gendata_h48h4k2/gendata_h48h4k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "4;2;20", "tables/h48h4k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 4, k = 2");
-
-        return 0;
-}
diff --git a/tools/0052_gendata_h48h5k2/gendata_h48h5k2.c b/tools/0052_gendata_h48h5k2/gendata_h48h5k2.c
deleted file mode 100644
index d292d49..0000000
--- a/tools/0052_gendata_h48h5k2/gendata_h48h5k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "5;2;20", "tables/h48h5k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 5, k = 2");
-
-        return 0;
-}
diff --git a/tools/0062_gendata_h48h6k2/gendata_h48h6k2.c b/tools/0062_gendata_h48h6k2/gendata_h48h6k2.c
deleted file mode 100644
index 910d514..0000000
--- a/tools/0062_gendata_h48h6k2/gendata_h48h6k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "6;2;20", "tables/h48h6k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 6, k = 2");
-
-        return 0;
-}
diff --git a/tools/0072_gendata_h48h7k2/gendata_h48h7k2.c b/tools/0072_gendata_h48h7k2/gendata_h48h7k2.c
deleted file mode 100644
index b803328..0000000
--- a/tools/0072_gendata_h48h7k2/gendata_h48h7k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "7;2;20", "tables/h48h7k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 7, k = 2");
-
-        return 0;
-}
diff --git a/tools/0082_gendata_h48h8k2/gendata_h48h8k2.c b/tools/0082_gendata_h48h8k2/gendata_h48h8k2.c
deleted file mode 100644
index 52c377a..0000000
--- a/tools/0082_gendata_h48h8k2/gendata_h48h8k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "8;2;20", "tables/h48h8k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 8, k = 2");
-
-        return 0;
-}
diff --git a/tools/0092_gendata_h48h9k2/gendata_h48h9k2.c b/tools/0092_gendata_h48h9k2/gendata_h48h9k2.c
deleted file mode 100644
index 5d3e34a..0000000
--- a/tools/0092_gendata_h48h9k2/gendata_h48h9k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "9;2;20", "tables/h48h9k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 9, k = 2");
-
-        return 0;
-}
diff --git a/tools/0102_gendata_h48h10k2/gendata_h48h10k2.c b/tools/0102_gendata_h48h10k2/gendata_h48h10k2.c
deleted file mode 100644
index 5e8fbb0..0000000
--- a/tools/0102_gendata_h48h10k2/gendata_h48h10k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "10;2;20", "tables/h48h10k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 10, k = 2");
-
-        return 0;
-}
diff --git a/tools/0112_gendata_h48h11k2/gendata_h48h11k2.c b/tools/0112_gendata_h48h11k2/gendata_h48h11k2.c
deleted file mode 100644
index 00c0747..0000000
--- a/tools/0112_gendata_h48h11k2/gendata_h48h11k2.c
+++ /dev/null
@@ -1,21 +0,0 @@
-#include "../tool.h"
-
-uint64_t expected[21] = {
-        /* Base value is 8 */
-        [0] = 0, /* Unknown */
-        [1] = 0, /* Unknown */
-        [2] = 0, /* Unknown */
-        [3] = 0, /* Unknown */
-};
-
-void run(void) {
-        gendata_run("h48", "11;2;20", "tables/h48h11k2", expected);
-}
-
-int main(void) {
-        nissy_setlogger(log_stderr);
-
-        timerun(run, "benchmark gendata_h48 h = 11, k = 2");
-
-        return 0;
-}
diff --git a/tools/100_checkdata/checkdata.c b/tools/100_checkdata/checkdata.c
new file mode 100644
index 0000000..05961c1
--- /dev/null
+++ b/tools/100_checkdata/checkdata.c
@@ -0,0 +1,52 @@
+#include "../tool.h"
+#include "../expected_distributions.h"
+
+char *solver, *options, *filename;
+
+static void
+run(void) {
+        int64_t size;
+        char *buf;
+        FILE *f;
+        
+        size = nissy_datasize(solver, options);
+
+        if (size <= 0) {
+                fprintf(stderr, "Error in datasize\n");
+                return;
+        }
+
+        if ((f = fopen(filename, "rb")) == NULL) {
+                fprintf(stderr, "Error reading file %s\n", filename);
+                return;
+        }
+
+        buf = malloc(size);
+        fread(buf, size, 1, f);
+        fclose(f);
+        nissy_checkdata(solver, options, buf);
+        free(buf);
+
+        /* TODO: cross-check with expected distributions? */
+}
+
+int main(int argc, char **argv) {
+        char description[256];
+
+        if (argc < 4) {
+                fprintf(stderr, "Error: not enough arguments. "
+                    "A solver, its options and a file name must be given.\n");
+                return 1;
+        }
+
+        solver = argv[1];
+        options = argv[2];
+        filename = argv[3];
+        sprintf(description, "checking data for solver %s"
+            "with options %s from file %s", solver, options, filename);
+        nissy_setlogger(log_stderr);
+
+        timerun(run, description);
+
+        return 0;
+}
diff --git a/tools/100_stats_tables_h48/stats_tables_h48.c b/tools/200_stats_tables_h48/stats_tables_h48.c
index adac8fa..adac8fa 100644
--- a/tools/100_stats_tables_h48/stats_tables_h48.c
+++ b/tools/200_stats_tables_h48/stats_tables_h48.c
diff --git a/tools/200_solve_small/solve_small.c b/tools/300_solve_small/solve_small.c
index d476bce..d476bce 100644
--- a/tools/200_solve_small/solve_small.c
+++ b/tools/300_solve_small/solve_small.c
diff --git a/tools/expected_distributions.h b/tools/expected_distributions.h
new file mode 100644
index 0000000..535cab2
--- /dev/null
+++ b/tools/expected_distributions.h
@@ -0,0 +1,33 @@
+uint64_t expected_h48[12][9][21] = {
+        [0] = {
+                [2] = {
+                        [0] = 5473562,
+                        [1] = 34776317,
+                        [2] = 68566704,
+                        [3] = 8750867,
+                },
+                [4] = {
+                        [0] = 1,
+                        [1] = 1,
+                        [2] = 4,
+                        [3] = 34,
+                        [4] = 331,
+                        [5] = 3612,
+                        [6] = 41605,
+                        [7] = 474128,
+                        [8] = 4953846,
+                        [9] = 34776317,
+                        [10] = 68566704,
+                        [11] = 8749194,
+                        [12] = 1673,
+                },
+        },
+        [1] = {
+                [2] = {
+                        [0] = 6012079,
+                        [1] = 45822302,
+                        [2] = 142018732,
+                        [3] = 41281787,
+                },
+        },
+};
diff --git a/tools/nissy_extra.h b/tools/nissy_extra.h
new file mode 100644
index 0000000..1e714a7
--- /dev/null
+++ b/tools/nissy_extra.h
@@ -0,0 +1,7 @@
+/*
+This header file exposes certain functions that are meant to be used
+for testing purposes only.
+*/
+
+size_t gendata_h48_derive(uint8_t, const void *, void *);
+int parse_h48_options(const char *, uint8_t *, uint8_t *, uint8_t *);
diff --git a/tools/run_tool.sh b/tools/run_tool.sh
index 7e09684..2216a66 100755
--- a/tools/run_tool.sh
+++ b/tools/run_tool.sh
@@ -5,7 +5,7 @@ if [ -z "$TOOL" ]; then
         exit 1
 fi
 
-CC="$CC -D_POSIX_C_SOURCE=199309L"
+CC="$CC -D_POSIX_C_SOURCE=199309L" # For timer
 
 BIN="tools/run"
 d="$(date +'%Y-%m-%d-%H-%M-%S')"
@@ -16,7 +16,8 @@ for t in tools/*; do
         fi
         toolname="$(basename "$t" .c)"
         $CC -o $BIN "$t"/*.c "$CUBEOBJ" || exit 1;
-        $BIN | tee "tools/results/$toolname-$d.txt" "tools/results/last.out"
+        $BIN $TOOLARGS \
+                | tee "tools/results/$toolname-$d.txt" "tools/results/last.out"
         break
 done
 
diff --git a/tools/tool.h b/tools/tool.h
index 757657b..c44828d 100644
--- a/tools/tool.h
+++ b/tools/tool.h
@@ -6,14 +6,19 @@
 #include <stdlib.h>
 
 #include "../src/nissy.h"
+#include "nissy_extra.h"
 
 static void log_stderr(const char *, ...);
 static void log_stdout(const char *, ...);
 static double timerun(void (*)(void), const char *);
+static void getfilename(const char *, const char *, char *);
 static void writetable(const char *, int64_t, const char *);
 static int64_t generatetable(const char *, const char *, char **);
+static int64_t derivetable(const char *, const char *, const char *, char **);
 static int getdata(const char *, const char *, char **, const char *);
-static void gendata_run(const char *, const char *, const char *, uint64_t[static 21]);
+static void gendata_run(const char *, const char *, uint64_t[static 21]);
+static void derivedata_run(
+    const char *, const char *, const char *, const char *);
 
 static void
 log_stderr(const char *str, ...)
@@ -70,6 +75,17 @@ timerun(void (*run)(void), const char *name)
 }
 
 static void
+getfilename(const char *solver, const char *options, char *filename)
+{
+        uint8_t h, k;
+
+        /* Only h48 supported for now */
+        parse_h48_options(options, &h, &k, NULL);
+
+        sprintf(filename, "tables/%sh%dk%d", solver, h, k);
+}
+
+static void
 writetable(const char *buf, int64_t size, const char *filename)
 {
         FILE *f;
@@ -109,6 +125,44 @@ generatetable(const char *solver, const char *options, char **buf)
         return gensize;
 }
 
+static int64_t
+derivetable(
+        const char *opts_large,
+        const char *opts_small,
+        const char *filename_large,
+        char **buf
+)
+{
+        uint8_t h;
+        int64_t size, gensize;
+        char *fulltable;
+
+        if (getdata("h48", opts_large, &fulltable, filename_large) != 0) {
+                printf("Error reading full table.\n");
+                return -1;
+        }
+
+        size = nissy_datasize("h48", opts_small);
+        if (size == -1) {
+                printf("Error getting table size.\n");
+                free(fulltable);
+                return -1;
+        }
+
+        h = atoi(opts_small); /* TODO: use option parser */
+        *buf = malloc(size);
+        gensize = gendata_h48_derive(h, fulltable, *buf);
+
+        if (gensize != size) {
+                fprintf(stderr, "Error deriving table\n");
+                free(fulltable);
+                return -2;
+        }
+
+        free(fulltable);
+        return gensize;
+}
+
 static int
 getdata(
         const char *solver,
@@ -155,13 +209,12 @@ static void
 gendata_run(
         const char *solver,
         const char *options,
-        const char *filename, /* TODO: remove filename, use solver name */
         uint64_t expected[static 21]
 ) {
         int64_t size;
-        char *buf;
+        char *buf, filename[1024];
 
-        
+        getfilename(solver, options, filename);
         size = generatetable(solver, options, &buf);
         switch (size) {
         case -1:
@@ -182,3 +235,34 @@ gendata_run(
 gendata_run_finish:
         free(buf);
 }
+
+static void
+derivedata_run(
+        const char *opts_large,
+        const char *opts_small,
+        const char *filename_large,
+        const char *filename_small
+)
+{
+        int64_t size;
+        char *buf;
+
+        size = derivetable(opts_large, opts_small, filename_large, &buf);
+        switch (size) {
+        case -1:
+                return;
+        case -2:
+                goto derivedata_run_finish;
+        default:
+                nissy_datainfo(buf, write_stdout);
+                printf("\n");
+                printf("Succesfully generated %" PRId64 " bytes. "
+                       "See above for details on the tables.\n", size);
+
+                writetable(buf, size, filename_small);
+                break;
+        }
+
+derivedata_run_finish:
+        free(buf);
+}