[IO] Change prefetcher content to NDArray, remove some of parameters

doc/python/io.md

@@ -40,7 +40,7 @@ The following code gives an example of creating a Cifar data iterator.
 >>>        # Dataset Paramter
 >>>        # Impulsary
 >>>        # indicating the image size after preprocessing
->>>        input_shape=(3,28,28),
+>>>        data_shape=(3,28,28),
 >>>        # Batch Paramter
 >>>        # Impulsary
 >>>        # tells how many images in a batch
@@ -51,7 +51,7 @@ The following code gives an example of creating a Cifar data iterator.
 >>>        mean_img="data/cifar/cifar10_mean.bin",
 >>>        # Augmentation Parameter
 >>>        # Optional
->>>        # randomly crop a patch of the input_shape from the original image
+>>>        # randomly crop a patch of the data_shape from the original image
 >>>        rand_crop=True,
 >>>        # Augmentation Parameter
 >>>        # Optional

example/python-howto/data_iter.py

@@ -14,18 +14,18 @@
         # Dataset/Augment Paramter
         # Impulsary
         # indicating the image size after preprocessing
-        input_shape=(3,28,28),
+        data_shape=(3,28,28),
         # Batch Paramter
         # Impulsary
         # tells how many images in a batch
-        batch_size=100,       
+        batch_size=100,
         # Augmentation Parameter
         # Optional
         # when offers mean_img, each image will substract the mean value at each pixel
         mean_img="data/cifar/cifar10_mean.bin",
         # Augmentation Parameter
         # Optional
-        # randomly crop a patch of the input_shape from the original image
+        # randomly crop a patch of the data_shape from the original image
         rand_crop=True,
         # Augmentation Parameter
         # Optional
@@ -42,7 +42,7 @@
         # Backend Parameter
         # Optional
         # Prefetch buffer size
-        prefetch_buffer=1)
+        prefetch_buffer=4)
 
 batchidx = 0
 for data, label in dataiter:

include/mxnet/io.h

@@ -55,22 +55,13 @@ struct DataInst {
 };  // struct DataInst
 
 /*!
- * \brief a standard batch of data commonly used by iterator
- *      a databatch contains multiple TBlobs. Each Tblobs has
- *      a name stored in a map. There's no different between
- *      data and label, how we use them is to see the DNN implementation.
+ * \brief DataBatch of NDArray, returned by Iterator
  */
 struct DataBatch {
- public:
   /*! \brief content of dense data, if this DataBatch is dense */
   std::vector<NDArray> data;
   /*! \brief extra data to be fed to the network */
   std::string extra_data;
- public:
-  /*! \brief constructor */
-  DataBatch(void) {}
-  /*! \brief destructor */
-  ~DataBatch() {}
 };  // struct DataBatch
 
 /*! \brief typedef the factory function of data iterator */
@@ -122,7 +113,7 @@ struct DataIteratorReg
  *
  * \code
  * // example of registering a imagerec iterator
- * MXNET_REGISTER_IO_CHAINED_ITERATOR(ImageRecordIter, 
+ * MXNET_REGISTER_IO_CHAINED_ITERATOR(ImageRecordIter,
  * ImageRecordIter, ImageRecBatchLoader, Prefetcher)
  * .describe("batched image record data iterator");
  *

src/io/image_augmenter.h

@@ -69,7 +69,7 @@ struct ImageAugmentParam : public dmlc::Parameter<ImageAugmentParam> {
   /*! \brief whether to print augment info */
   bool silent;
   /*! \brief shape of the image data*/
-  TShape input_shape;
+  TShape data_shape;
   // declare parameters
   DMLC_DECLARE_PARAMETER(ImageAugmentParam) {
     DMLC_DECLARE_FIELD(rand_crop).set_default(true)
@@ -120,9 +120,9 @@ struct ImageAugmentParam : public dmlc::Parameter<ImageAugmentParam> {
         .describe("Augmentation Param: Maximum value of illumination variation.");
     DMLC_DECLARE_FIELD(silent).set_default(true)
         .describe("Augmentation Param: Whether to print augmentor info.");
-    index_t input_shape_default[] = {3, 224, 224};
-    DMLC_DECLARE_FIELD(input_shape)
-        .set_default(TShape(input_shape_default, input_shape_default + 3))
+    index_t data_shape_default[] = {3, 224, 224};
+    DMLC_DECLARE_FIELD(data_shape)
+        .set_default(TShape(data_shape_default, data_shape_default + 3))
         .set_expect_ndim(3).enforce_nonzero()
         .describe("Dataset Param: Input shape of the neural net.");
   }
@@ -234,20 +234,20 @@ class ImageAugmenter {
         y /= 2; x /= 2;
       }
       cv::Rect roi(x, y, rand_crop_size, rand_crop_size);
-      cv::resize(res(roi), res, cv::Size(param_.input_shape[1], param_.input_shape[2]));
+      cv::resize(res(roi), res, cv::Size(param_.data_shape[1], param_.data_shape[2]));
     } else {
-        CHECK(static_cast<mshadow::index_t>(res.cols) >= param_.input_shape[1] \
-                && static_cast<mshadow::index_t>(res.rows) >= param_.input_shape[2])
+        CHECK(static_cast<mshadow::index_t>(res.cols) >= param_.data_shape[1] \
+                && static_cast<mshadow::index_t>(res.rows) >= param_.data_shape[2])
             << "input image size smaller than input shape";
-        mshadow::index_t y = res.rows - param_.input_shape[2];
-        mshadow::index_t x = res.cols - param_.input_shape[1];
+        mshadow::index_t y = res.rows - param_.data_shape[2];
+        mshadow::index_t x = res.cols - param_.data_shape[1];
         if (param_.rand_crop != 0) {
             y = NextUInt32(y + 1, prnd);
             x = NextUInt32(x + 1, prnd);
         } else {
             y /= 2; x /= 2;
         }
-        cv::Rect roi(x, y, param_.input_shape[1], param_.input_shape[2]);
+        cv::Rect roi(x, y, param_.data_shape[1], param_.data_shape[2]);
         res = res(roi);
     }
     return res;
@@ -300,24 +300,24 @@ class ImageAugmenter {
       }
     }
     img_.Resize(mshadow::Shape3((*p_data).shape_[0],
-                param_.input_shape[1], param_.input_shape[2]));
-    if (param_.input_shape[1] == 1) {
+                param_.data_shape[1], param_.data_shape[2]));
+    if (param_.data_shape[1] == 1) {
       img_ = (*p_data) * param_.scale;
     } else {
-      CHECK(p_data->size(1) >= param_.input_shape[1] && p_data->size(2) >= param_.input_shape[2])
+      CHECK(p_data->size(1) >= param_.data_shape[1] && p_data->size(2) >= param_.data_shape[2])
           << "Data size must be bigger than the input size to net.";
-      mshadow::index_t yy = p_data->size(1) - param_.input_shape[1];
-      mshadow::index_t xx = p_data->size(2) - param_.input_shape[2];
+      mshadow::index_t yy = p_data->size(1) - param_.data_shape[1];
+      mshadow::index_t xx = p_data->size(2) - param_.data_shape[2];
       if (param_.rand_crop != 0 && (yy != 0 || xx != 0)) {
         yy = NextUInt32(yy + 1, prnd);
         xx = NextUInt32(xx + 1, prnd);
       } else {
         yy /= 2; xx /= 2;
       }
-      if (p_data->size(1) != param_.input_shape[1] && param_.crop_y_start != -1) {
+      if (p_data->size(1) != param_.data_shape[1] && param_.crop_y_start != -1) {
         yy = param_.crop_y_start;
       }
-      if (p_data->size(2) != param_.input_shape[2] && param_.crop_x_start != -1) {
+      if (p_data->size(2) != param_.data_shape[2] && param_.crop_x_start != -1) {
         xx = param_.crop_x_start;
       }
       float contrast = NextDouble(prnd) * param_.max_random_contrast \

src/io/iter_batchloader.h

@@ -1,7 +1,7 @@
 /*!
  *  Copyright (c) 2015 by Contributors
  * \file iter_batchloader.h
- * \brief define a batch adapter to create tblob batch 
+ * \brief define a batch adapter to create tblob batch
  */
 #ifndef MXNET_IO_ITER_BATCHLOADER_H_
 #define MXNET_IO_ITER_BATCHLOADER_H_
@@ -22,30 +22,26 @@ struct BatchParam : public dmlc::Parameter<BatchParam> {
   /*! \brief label width */
   index_t batch_size;
   /*! \brief input shape */
-  TShape input_shape;
+  TShape data_shape;
   /*! \brief label width */
   index_t label_width;
   /*! \brief use round roubin to handle overflow batch */
   bool round_batch;
-  /*! \brief skip read */
-  bool test_skipread;
   /*! \brief silent */
   bool silent;
   // declare parameters
   DMLC_DECLARE_PARAMETER(BatchParam) {
     DMLC_DECLARE_FIELD(batch_size)
         .describe("Batch Param: Batch size.");
-    index_t input_shape_default[] = {3, 224, 224};
-    DMLC_DECLARE_FIELD(input_shape)
-        .set_default(TShape(input_shape_default, input_shape_default + 3))
+    index_t data_shape_default[] = {3, 224, 224};
+    DMLC_DECLARE_FIELD(data_shape)
+        .set_default(TShape(data_shape_default, data_shape_default + 3))
         .set_expect_ndim(3).enforce_nonzero()
-        .describe("Dataset Param: Input shape of the neural net.");
+        .describe("Dataset Param: Shape of each instance generated by the DataIter.");
     DMLC_DECLARE_FIELD(label_width).set_default(1)
         .describe("Dataset Param: Label width.");
     DMLC_DECLARE_FIELD(round_batch).set_default(true)
         .describe("Batch Param: Use round robin to handle overflow batch.");
-    DMLC_DECLARE_FIELD(test_skipread).set_default(false)
-        .describe("Batch Param: Skip read for testing.");
     DMLC_DECLARE_FIELD(silent).set_default(false)
         .describe("Batch Param: Whether to print batch information.");
   }
@@ -70,8 +66,9 @@ class BatchLoader : public IIterator<TBlobBatch> {
     base_->Init(kwargs);
     std::vector<size_t> data_shape_vec;
     data_shape_vec.push_back(param_.batch_size);
-    for (size_t shape_dim = 0; shape_dim < param_.input_shape.ndim(); shape_dim++)
-        data_shape_vec.push_back(param_.input_shape[shape_dim]);
+    for (size_t shape_dim = 0; shape_dim < param_.data_shape.ndim(); ++shape_dim) {
+      data_shape_vec.push_back(param_.data_shape[shape_dim]);
+    }
     data_shape_ = TShape(data_shape_vec.begin(), data_shape_vec.end());
     std::vector<size_t> label_shape_vec;
     label_shape_vec.push_back(param_.batch_size);
@@ -96,12 +93,7 @@ class BatchLoader : public IIterator<TBlobBatch> {
   }
   inline bool Next(void) {
     out_.num_batch_padd = 0;
-
-    // skip read if in head version
-    if (param_.test_skipread != 0 && head_ == 0)
-        return true;
-    else
-        this->head_ = 0;
+    this->head_ = 0;
 
     // if overflow from previous round, directly return false, until before first is called
     if (num_overflow_ != 0) return false;

src/io/iter_image_recordio.cc

@@ -93,14 +93,10 @@ struct ImageRecParserParam : public dmlc::Parameter<ImageRecParserParam> {
   std::string path_imglist;
   /*! \brief path to image recordio */
   std::string path_imgrec;
-  /*! \brief virtually split the data into n parts */
-  int num_parts;
-  /*! \brief only read the i-th part */
-  int part_index;
   /*! \brief label-width */
   int label_width;
   /*! \brief input shape */
-  TShape input_shape;
+  TShape data_shape;
   /*! \brief number of threads */
   int preprocess_threads;
   /*! \brief whether to remain silent */
@@ -113,15 +109,11 @@ struct ImageRecParserParam : public dmlc::Parameter<ImageRecParserParam> {
         .describe("Dataset Param: Path to image record file.");
     DMLC_DECLARE_FIELD(label_width).set_lower_bound(1).set_default(1)
         .describe("Dataset Param: How many labels for an image.");
-    DMLC_DECLARE_FIELD(num_parts).set_lower_bound(1).set_default(1)
-        .describe("Dataset Param: virtually split the data into n parts");
-    DMLC_DECLARE_FIELD(part_index).set_default(0)
-        .describe("Dataset Param: only read the i-th part");
-    index_t input_shape_default[] = {3, 224, 224};
-    DMLC_DECLARE_FIELD(input_shape)
-        .set_default(TShape(input_shape_default, input_shape_default + 3))
+    index_t data_shape_default[] = {3, 224, 224};
+    DMLC_DECLARE_FIELD(data_shape)
+        .set_default(TShape(data_shape_default, data_shape_default + 3))
         .enforce_nonzero()
-        .describe("Dataset Param: Input shape of the neural net");
+        .describe("Dataset Param: Shape of each instance generated by the DataIter.");
     DMLC_DECLARE_FIELD(preprocess_threads).set_lower_bound(1).set_default(4)
         .describe("Backend Param: Number of thread to do preprocessing.");
     DMLC_DECLARE_FIELD(silent).set_default(false)
@@ -184,8 +176,8 @@ inline void ImageRecordIOParser::Init(
   int maxthread, threadget;
   #pragma omp parallel
   {
-    // why ? (muli)
-    maxthread = std::max(omp_get_num_procs() / 2 - 1, 1);
+    // be conservative, set number of real cores
+    maxthread = std::max(omp_get_num_procs() / 2, 1);
   }
   param_.preprocess_threads = std::min(maxthread, param_.preprocess_threads);
   #pragma omp parallel num_threads(param_.preprocess_threads)
@@ -208,9 +200,12 @@ inline void ImageRecordIOParser::Init(
   CHECK(param_.path_imgrec.length() != 0)
     << "ImageRecordIOIterator: must specify image_rec";
 
+  // TODO(mu, tianjun) add DMLC env variable to detect parition
+  const int part_index = 0;
+  const int num_parts = 1;
   source_ = dmlc::InputSplit::Create(
-      param_.path_imgrec.c_str(), param_.part_index,
-      param_.num_parts, "recordio");
+      param_.path_imgrec.c_str(), part_index,
+      num_parts, "recordio");
   // use 64 MB chunk when possible
   source_->HintChunkSize(8 << 20UL);
 #else
@@ -279,7 +274,7 @@ ParseNext(std::vector<InstVector> *out_vec) {
     out.Clear();
     for (size_t j = 0; j < opencv_out.Size(); j++) {
       out.Push(opencv_out.Index(j),
-               mshadow::Shape3(param_.input_shape[0], param_.input_shape[1], param_.input_shape[2]),
+               mshadow::Shape3(param_.data_shape[0], param_.data_shape[1], param_.data_shape[2]),
                mshadow::Shape1(param_.label_width));
       DataInst inst = out.Back();
       DataInst opencv_inst = opencv_out[j];