Merge pull request #420 from cmusphinx/kal-ps-lm-convert

Fix pocketsphinx_lm_convert failing due to missing lw/wip parameters

Author: lenzo-ka

src/lm/ngram_model.c

@@ -165,8 +165,13 @@ ngram_model_read(cmd_ln_t * config,
         float32 lw = 1.0;
         float32 wip = 1.0;
 
-        lw = ps_config_float(config, "lw");
-        wip = ps_config_float(config, "wip");
+        /* Only read weights if they are defined in the config.
+         * This allows tools like pocketsphinx_lm_convert to work
+         * without defining these decoder-specific parameters. */
+        if (ps_config_typeof(config, "lw"))
+            lw = ps_config_float(config, "lw");
+        if (ps_config_typeof(config, "wip"))
+            wip = ps_config_float(config, "wip");
 
         ngram_model_apply_weights(model, lw, wip);
     }

test/unit/CMakeLists.txt

@@ -16,6 +16,7 @@ set(TESTS
   test_jsgf
   test_keyphrase
   test_lattice
+  test_lm_convert
   test_ngram_model_read
   test_log_shifted
   test_log_int8

test/unit/test_lm_convert.c

@@ -0,0 +1,57 @@
+/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/**
+ * Test that pocketsphinx_lm_convert works without lw/wip parameters
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include <pocketsphinx.h>
+#include "util/cmd_ln.h"
+#include "lm/ngram_model.h"
+
+#include "test_macros.h"
+
+static const ps_arg_t defn[] = {
+    { "logbase",
+      ARG_FLOATING,
+      "1.0001",
+      "Base in which all log-likelihoods calculated" },
+    { "mmap",
+      ARG_BOOLEAN,
+      "no",
+      "Use memory-mapped I/O for reading binary LM files"},
+    { NULL, 0, NULL, NULL }
+};
+
+int
+main(int argc, char *argv[])
+{
+    ps_config_t *config;
+    ngram_model_t *lm;
+    logmath_t *lmath;
+
+    (void)argc;
+    (void)argv;
+
+    /* Create a minimal config without lw/wip parameters */
+    config = ps_config_init(defn);
+    TEST_ASSERT(config != NULL);
+
+    /* Create log math object */
+    lmath = logmath_init(1.0001, 0, 0);
+    TEST_ASSERT(lmath != NULL);
+
+    /* Try to read a language model - this should work without errors */
+    lm = ngram_model_read(config, DATADIR "/turtle.lm.bin",
+                          NGRAM_AUTO, lmath);
+    TEST_ASSERT(lm != NULL);
+
+    /* Clean up */
+    ngram_model_free(lm);
+    logmath_free(lmath);
+    ps_config_free(config);
+
+    return 0;
+}