diff --git a/src/minibatch.c b/src/minibatch.c
new file mode 100644
index 00000000..2c886876
--- /dev/null
+++ b/src/minibatch.c
@@ -0,0 +1,215 @@
+#include "minibatch.h"
+#include "float_utils.h"
+
+#define BIAS_FEATURE_ID 0
+
+bool count_features_minibatch(khash_t(str_double) *feature_counts, feature_count_array *minibatch, bool unique) {
+    const char *feature;
+    uint32_t feature_id;
+    double count;
+
+    size_t i;
+    size_t m = minibatch->n;
+
+    for (i = 0; i < minibatch->n; i++) {
+        khash_t(str_double) *counts = minibatch->a[i];
+
+        kh_foreach(counts, feature, count, {
+            // If unique is true, count features once per example
+            double value = unique ? 1.0 : count;
+            if (!feature_counts_add(feature_counts, (char *)feature, value)) {
+                return false;
+            }
+        })
+    }
+
+    return true;
+}
+
+bool count_labels_minibatch(khash_t(str_uint32) *label_ids, cstring_array *labels) {
+    uint32_t i;
+    char *label;
+
+    cstring_array_foreach(labels, i, label, {
+        khiter_t k = kh_get(str_uint32, label_ids, label);
+
+        if (k != kh_end(label_ids)) {
+            kh_value(label_ids, k)++;
+        } else {
+            int ret = 0;
+            k = kh_put(str_uint32, label_ids, strdup(label), &ret);
+            if (ret < 0) {
+                return false;
+            }
+            kh_value(label_ids, k) = 1;
+        }
+
+    })
+
+    return true;
+}
+
+trie_t *select_features_threshold(khash_t(str_double) *feature_counts, double threshold) {
+    const char *feature;
+    double count;
+
+    int ret = 0;
+    // First feature is the bias unit, so start from 1
+    uint32_t feature_id = 1;
+
+    khash_t(str_uint32) *feature_ids = kh_init(str_uint32);
+
+    size_t n = kh_size(feature_counts);
+
+    bool reversed = true;
+    char **sorted_keys = str_double_hash_sort_keys_by_value(feature_counts, reversed);
+    log_info("Sort done\n");
+
+    for (size_t i = 0; i < n; i++) {
+        char *key = sorted_keys[i];
+        khiter_t k = kh_get(str_double, feature_counts, key);
+        if (k == kh_end(feature_counts)) {
+            goto exit_destroy_feature_ids;
+        }
+
+        if (strlen(key) == 0) continue;
+
+        count = kh_value(feature_counts, k);
+        if (count < threshold && !double_equals(count, threshold)) continue;
+
+        // feature_ids is a local hash, don't need to strdup the key on put
+        k = kh_put(str_uint32, feature_ids, key, &ret);
+        if (ret < 0) {
+            goto exit_destroy_feature_ids;
+        }
+
+        kh_value(feature_ids, k) = feature_id++;
+    }
+
+    trie_t *trie = trie_new_from_hash(feature_ids);
+
+    free(sorted_keys);
+    kh_destroy(str_uint32, feature_ids);
+    return trie;
+
+exit_destroy_feature_ids:
+    free(sorted_keys);
+    kh_destroy(str_uint32, feature_ids);
+    return NULL;
+}
+
+khash_t(str_uint32) *select_labels_threshold(khash_t(str_uint32) *label_counts, uint32_t threshold) {
+    const char *label;
+    uint32_t count;
+
+    int ret = 0;
+    uint32_t label_id = 0;
+
+    khash_t(str_uint32) *label_ids = kh_init(str_uint32);
+
+    size_t n = kh_size(label_counts);
+
+    bool reversed = true;
+    char **sorted_keys = str_uint32_hash_sort_keys_by_value(label_counts, reversed);
+
+    for (size_t i = 0; i < n; i++) {
+        char *label = sorted_keys[i];
+        khiter_t k = kh_get(str_uint32, label_counts, label);
+        if (k == kh_end(label_counts)) {
+            goto exit_destroy_label_ids;
+        }
+
+        count = kh_value(label_counts, k);
+        if (count < threshold) continue;
+
+        k = kh_put(str_uint32, label_ids, label, &ret);
+        if (ret < 0) {
+            goto exit_destroy_label_ids;
+        }
+
+        kh_value(label_ids, k) = label_id++;
+    }
+
+    free(sorted_keys);
+    return label_ids;
+exit_destroy_label_ids:
+    free(sorted_keys);
+    kh_destroy(str_uint32, label_ids);
+    return NULL;
+
+}
+
+
+sparse_matrix_t *feature_matrix(trie_t *feature_ids, feature_count_array *feature_counts) {
+    const char *feature;
+    uint32_t feature_id;
+    double count;
+
+    size_t i;
+    size_t m = feature_counts->n;
+    // Add one feature for bias unit
+    size_t n = trie_num_keys(feature_ids) + 1;
+
+    sparse_matrix_t *matrix = sparse_matrix_new_shape(m, n);
+
+    for (i = 0; i < m; i++) {
+        khash_t(str_double) *counts = feature_counts->a[i];
+        sparse_matrix_append(matrix, BIAS_FEATURE_ID, 1.0);
+
+        kh_foreach(counts, feature, count, {
+            if (!trie_get_data(feature_ids, (char *)feature, &feature_id)) {
+                continue;
+            }
+            sparse_matrix_append(matrix, feature_id, count);
+        })
+
+        sparse_matrix_finalize_row(matrix);
+    }
+
+    return matrix;
+}
+
+sparse_matrix_t *feature_vector(trie_t *feature_ids, khash_t(str_double) *feature_counts) {
+    const char *feature;
+    uint32_t feature_id;
+    double count;
+
+    size_t m = 1;
+    // Add one feature for bias unit
+    size_t n = trie_num_keys(feature_ids) + 1;
+
+    sparse_matrix_t *matrix = sparse_matrix_new_shape(m, n);
+
+    sparse_matrix_append(matrix, BIAS_FEATURE_ID, 1.0);
+    kh_foreach(feature_counts, feature, count, {
+        if (!trie_get_data(feature_ids, (char *)feature, &feature_id)) {
+            continue;
+        }
+        sparse_matrix_append(matrix, feature_id, count);
+    })
+
+    sparse_matrix_finalize_row(matrix);
+
+    return matrix;   
+}
+
+uint32_array *label_vector(khash_t(str_uint32) *label_ids, cstring_array *labels) {
+    uint32_t i;
+    char *label;
+    uint32_t label_id;
+
+    uint32_array *array = uint32_array_new_size(cstring_array_num_strings(labels));
+
+    cstring_array_foreach(labels, i, label, {
+        khiter_t k = kh_get(str_uint32, label_ids, label);
+
+        if (k != kh_end(label_ids)) {
+            label_id = kh_value(label_ids, k);
+            uint32_array_push(array, label_id);
+        }
+
+    });
+
+    return array;
+}
+
diff --git a/src/minibatch.h b/src/minibatch.h
new file mode 100644
index 00000000..c07cea1f
--- /dev/null
+++ b/src/minibatch.h
@@ -0,0 +1,26 @@
+#ifndef MINIBATCH_H
+#define MINIBATCH_H
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "collections.h"
+#include "features.h"
+#include "sparse_matrix.h"
+#include "trie.h"
+#include "trie_utils.h"
+#include "vector_math.h"
+
+
+bool count_features_minibatch(khash_t(str_double) *feature_counts, feature_count_array *minibatch, bool unique);
+bool count_labels_minibatch(khash_t(str_uint32) *label_counts, cstring_array *labels);
+
+trie_t *select_features_threshold(khash_t(str_double) *feature_counts, double threshold);
+khash_t(str_uint32) *select_labels_threshold(khash_t(str_uint32) *label_counts, uint32_t threshold);
+
+sparse_matrix_t *feature_matrix(trie_t *feature_ids, feature_count_array *feature_counts);
+sparse_matrix_t *feature_vector(trie_t *feature_ids, khash_t(str_double) *feature_counts);
+uint32_array *label_vector(khash_t(str_uint32) *label_ids, cstring_array *labels);
+
+
+#endif
\ No newline at end of file