The Dimension problem of Tensorflow in calculating loss

running a simple CNN model, the picture shows 64X64
the first layer convolution is 8X5X5, pooled into 5X5, step size is 2;
second layer convolution is 16X5X5, pooled is 5X5, step size is 2;
third layer convolution is 32X1X1, pooled into global pooled 16X16
output 1X1X32 eigenvalues, after flattening, input full connection layer
fourth layer full connection layer output is 2-D

batch_size is 20
but keeps reporting dimension errors when using sparse_softmax_cross_entropy to calculate cross entropy loss:
logits and labels must have the same first dimension, got logits shape [1280Jing 2] and labels shape [20]

the code is as follows:

-sharp -*- coding: utf-8 -*-

-sharp Steganalysis with High-Level API 

-sharp import dataset
import load_record

import tensorflow as tf
import numpy as np
import layer_module

flags = tf.app.flags

flags.DEFINE_integer("num_epochs", 10, "Number of training epochs")
flags.DEFINE_integer("batch_size", 20, "Batch size")
flags.DEFINE_float("learning_rate", 0.01, "Learning rate")
flags.DEFINE_float("dropout_rate", 0.5, "Dropout rate")

flags.DEFINE_string("train_dataset", "./dataset/train512.tfrecords",
                    "Filename of training dataset")
flags.DEFINE_string("eval_dataset", "./dataset/test512.tfrecords",
                    "Filename of evaluation dataset")
flags.DEFINE_string("test_dataset", "./dataset/test512.tfrecords",
                    "Filename of testing dataset")
flags.DEFINE_string("model_dir", "models/steganalysis_cnn_model",
                    "Filename of testing dataset")

FLAGS = flags.FLAGS

def stg_model_fn(features, labels, mode):
    -sharp Input Layer
    x = tf.reshape(features, [-1, 64, 64, 1])
    -sharp print(x)
    x = layer_module.conv_group(
        inputs = x,
        activation = "tanh",
        filters = 8,
        kernel_size = [5, 5],
        pool_size = 5,
        strides = 2,
        abs_layer = True,
        pool_padding = "same")
    print(x)

    x = layer_module.conv_group(
        inputs = x,
        filters = 16,
        activation = "tanh",
        kernel_size = [5, 5],
        pool_size = 5,
        strides = 2,
        abs_layer = False,
        pool_padding = "same")
    print(x)

    x = layer_module.conv_group(
        inputs = x,
        filters = 32,
        activation = "relu",
        kernel_size = [1, 1],
        pool_size = 16,
        strides = 1,
        abs_layer = False,
        pool_padding = "valid")
    print(x)


    x = tf.reshape(x, [-1, 32])
    x = tf.layers.dense(inputs = x, units = 2)
    
    -sharp x = tf.contrib.layers.flatten(inputs = x)
    with tf.Session() as sess:
        sess.run(tf.global_variables_initializer())
        print(tf.nn.softmax(x, name="softmax_tensor").eval(), labels.shape)
    predictions = {
        -sharp Generate predictions (for PREDICT and EVAL mode)
        "classes": tf.argmax(input=x, axis=1),
        -sharp Add `softmax_tensor` to the graph. It is used for PREDICT and by the
        -sharp `logging_hook`.
        "probabilities": tf.nn.softmax(x, name="softmax_tensor")
        }
    
    if mode == tf.estimator.ModeKeys.PREDICT:
        return tf.estimator.EstimatorSpec(mode=mode, predictions=predictions)
        -sharp Calculate Loss (for both TRAIN and EVAL modes)
    onehot_labels = tf.one_hot(indices=tf.cast(labels, tf.int32), depth=2)
    
    loss = tf.losses.sparse_softmax_cross_entropy(labels = labels, logits = x)
        -sharp Configure the Training Op (for TRAIN mode)
    if mode == tf.estimator.ModeKeys.TRAIN:
        optimizer = tf.train.GradientDescentOptimizer(learning_rate=FLAGS.learning_rate)
        train_op = optimizer.minimize(
            loss=loss,
            global_step=tf.train.get_global_step())
        return tf.estimator.EstimatorSpec(mode=mode, loss=loss, train_op=train_op)
        -sharp Add evaluation metrics (for EVAL mode)
    eval_metric_ops = {
            "accuracy": tf.metrics.accuracy(
                labels=labels, predictions=predictions["classes"])}
    return tf.estimator.EstimatorSpec(
            mode=mode, loss=loss, eval_metric_ops=eval_metric_ops)

def parser(record):
    keys_to_features = {
        "img_raw": tf.FixedLenFeature((), tf.string),
        "label": tf.FixedLenFeature((), tf.int64)
    }
    parsed = tf.parse_single_example(record, keys_to_features)
    image = tf.decode_raw(parsed["img_raw"], tf.uint8)
    image = tf.cast(image, tf.float32)
    label = tf.cast(parsed["label"], tf.int32)
    return image, label


def save_hp_to_json():
    """Save hyperparameters to a json file"""
    filename = os.path.join(FLAGS.model_dir, "hparams.json")
    hparams = FLAGS.flag_values_dict()
    with open(filename, "w") as f:
        json.dump(hparams, f, indent=4, sort_keys=True)

def main(unused_argv):

    def train_input_fn():
        train_dataset = tf.data.TFRecordDataset(FLAGS.train_dataset)
        train_dataset = train_dataset.map(parser)
        train_dataset = train_dataset.repeat(FLAGS.num_epochs)
        train_dataset = train_dataset.batch(FLAGS.batch_size)
        train_iterator = train_dataset.make_one_shot_iterator()

        features, labels = train_iterator.get_next()
        return features, labels

    def eval_input_fn():
        eval_dataset = tf.data.TFRecordDataset(FLAGS.eval_dataset)
        eval_dataset = eval_dataset.map(parser)
        -sharp eval_dataset = eval_dataset.repeat(FLAGS.num_epochs)
        eval_dataset = eval_dataset.batch(FLAGS.batch_size)
        eval_iterator = eval_dataset.make_one_shot_iterator()
        features, labels = eval_iterator.get_next()
        return features, labels

    steg_classifier = tf.estimator.Estimator(
        model_fn=stg_model_fn, model_dir=FLAGS.model_dir)

    -sharp Train
    steg_classifier.train(input_fn=train_input_fn)

    -sharp Evaluation
    eval_results = steg_classifier.evaluate(input_fn=eval_input_fn)
    print(eval_results)

    tf.logging.info("Saving hyperparameters ...")


if __name__ == "__main__":
    tf.app.run()

I don"t know where that 1280 came from. Mingming batch _ size is only 20

. < hr >

add the code for layer_module:

def conv_group(inputs, activation, filters, kernel_size, pool_size, strides, pool_padding, abs_layer):
    x = tf.layers.conv2d(
        inputs = inputs,
        filters = filters,
        kernel_size = kernel_size,
        padding = "same")

    if (abs_layer):
        x = tf.abs(x)

    x = tf.layers.batch_normalization(inputs = x)

    if (activation == "relu"):
        x = tf.nn.relu(x)
    elif (activation == "tanh"):
        x = tf.nn.tanh(x)
    print(x)
    x = tf.layers.average_pooling2d(
        inputs = x,
        padding = pool_padding,
        pool_size = pool_size,
        strides = strides)
    print(x)
    return x
Mar.04,2021

has solved the problem of reshape.

the picture is entered after 512X512X1 reshape becomes 64X64 (this is the wrong usage), since the first element of shape is-1, it means that the batch_size will be resized so that the total size remains the same. So batch_size becomes 20X (512) X (64) X () = 20X8X8 = 1280

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