Beginner's Guide for Caffe2DML users

Caffe2DML is an experimental API that converts a Caffe specification to DML. It is designed to fit well into the mllearn framework and hence supports NumPy, Pandas as well as PySpark DataFrame.

Training Lenet

To create a Caffe2DML object, one needs to create a solver and network file that conforms to the Caffe specification. In this example, we will train Lenet which is a simple convolutional neural network, proposed by Yann LeCun in 1998. It has 2 convolutions/pooling and fully connected layer. Similar to Caffe, the network has been modified to add dropout. For more detail, please see

The solver specification specifies to Caffe2DML to use following configuration when generating the training DML script:

from systemml.mllearn import Caffe2DML
import urllib

# Download the Lenet network
urllib.urlretrieve('', 'lenet.proto')
urllib.urlretrieve('', 'lenet_solver.proto')
# Train Lenet On MNIST using scikit-learn like API

# MNIST dataset contains 28 X 28 gray-scale (number of channel=1).
lenet = Caffe2DML(spark, solver='lenet_solver.proto', input_shape=(1, 28, 28))


| Name|           Type|        Output|      Weight|     Bias|        Top|   Bottom|Memory* (train/test)|
|mnist|           Data| (, 1, 28, 28)|            |         |mnist,mnist|         |                 1/0|
|conv1|    Convolution|(, 32, 28, 28)|   [32 X 25]| [32 X 1]|      conv1|    mnist|               25/12|
|relu1|           ReLU|(, 32, 28, 28)|            |         |      relu1|    conv1|               25/12|
|pool1|        Pooling|(, 32, 14, 14)|            |         |      pool1|    relu1|                 6/3|
|conv2|    Convolution|(, 64, 14, 14)|  [64 X 800]| [64 X 1]|      conv2|    pool1|                38/7|
|relu2|           ReLU|(, 64, 14, 14)|            |         |      relu2|    conv2|                12/6|
|pool2|        Pooling|  (, 64, 7, 7)|            |         |      pool2|    relu2|                 3/2|
|  ip1|   InnerProduct| (, 512, 1, 1)|[3136 X 512]|[1 X 512]|        ip1|    pool2|              797/13|
|relu3|           ReLU| (, 512, 1, 1)|            |         |      relu3|      ip1|                 1/0|
|drop1|        Dropout| (, 512, 1, 1)|            |         |      drop1|    relu3|                 1/0|
|  ip2|   InnerProduct|  (, 10, 1, 1)|  [512 X 10]| [1 X 10]|        ip2|    drop1|                 3/0|
| loss|SoftmaxWithLoss|  (, 10, 1, 1)|            |         |       loss|ip2,mnist|                 0/0|

Total number of layer outputs/errors/weights/bias/gradients: 5568768/5568768/1662752/618/106455680
Total memory requirements for parameters* for train/test: 910/55
[Advanced] Key network statistics to compute intermediate CP overhead batchSize/maxThreads/1-thread im2col*(sum, max)/1-thread reshape_col*(sum, max): 64/48/(1, 1)/(0, 0).
* => memory in megabytes assuming the parameters are in double precision and in dense format.

To train the above lenet model, we use the MNIST dataset. The MNIST dataset was constructed from two datasets of the US National Institute of Standards and Technology (NIST). The training set consists of handwritten digits from 250 different people, 50 percent high school students, and 50 percent employees from the Census Bureau. Note that the test set contains handwritten digits from different people following the same split. In this example, we are using mlxtend package to load the mnist dataset into Python NumPy arrays, but you are free to download it directly from

pip install mlxtend

We first split the MNIST dataset into train and test.

from import mnist_data
import numpy as np
from sklearn.utils import shuffle
# Download the MNIST dataset
X, y = mnist_data()
X, y = shuffle(X, y)
# Split the data into training and test
n_samples = len(X)
X_train = X[:int(.9 * n_samples)]
y_train = y[:int(.9 * n_samples)]
X_test = X[int(.9 * n_samples):]
y_test = y[int(.9 * n_samples):]

Finally, we use the training and test dataset to perform training and prediction using scikit-learn like API.

# Since Caffe2DML is a mllearn API, it allows for scikit-learn like method for training., y_train)
# Either perform prediction: lenet.predict(X_test) or scoring:
lenet.score(X_test, y_test)


Iter:100, training loss:0.189008481420049, training accuracy:92.1875
Iter:200, training loss:0.21657020576713149, training accuracy:96.875
Iter:300, training loss:0.05780939180052287, training accuracy:98.4375
Iter:400, training loss:0.03406193840071965, training accuracy:100.0
Iter:500, training loss:0.02847187709112875, training accuracy:100.0
Iter:500, validation loss:222.736109642486, validation accuracy:96.49077868852459
Iter:600, training loss:0.04867848427394318, training accuracy:96.875
Iter:700, training loss:0.043060905384304224, training accuracy:98.4375
Iter:800, training loss:0.01861298388336358, training accuracy:100.0
Iter:900, training loss:0.03495462005933769, training accuracy:100.0
Iter:1000, training loss:0.04598737325942163, training accuracy:98.4375
Iter:1000, validation loss:180.04232316810746, validation accuracy:97.28483606557377
Iter:1100, training loss:0.05630274512793694, training accuracy:98.4375
Iter:1200, training loss:0.027278141291535066, training accuracy:98.4375
Iter:1300, training loss:0.04356275106270366, training accuracy:98.4375
Iter:1400, training loss:0.00780793048139091, training accuracy:100.0
Iter:1500, training loss:0.004135965492374173, training accuracy:100.0
Iter:1500, validation loss:156.61636761709374, validation accuracy:97.48975409836065
Iter:1600, training loss:0.007939063305475983, training accuracy:100.0
Iter:1700, training loss:0.0025769653351162196, training accuracy:100.0
Iter:1800, training loss:0.0023251742357435204, training accuracy:100.0
Iter:1900, training loss:0.0016795711023936644, training accuracy:100.0
Iter:2000, training loss:0.03676045262879483, training accuracy:98.4375
Iter:2000, validation loss:173.66147359346, validation accuracy:97.48975409836065

Additional Configuration

Unlike Caffe where default train and test algorithm is minibatch, you can specify the algorithm using the parameters train_algo and test_algo (valid values are: minibatch, allreduce_parallel_batches, and allreduce). Here are some common settings:

  PySpark script Changes to Network/Solver
Single-node CPU execution (similar to Caffe with solver_mode: CPU) lenet.set(train_algo="minibatch", test_algo="minibatch") Ensure that batch_size is set to appropriate value (for example: 64)
Single-node single-GPU execution lenet.set(train_algo="minibatch", test_algo="minibatch").setGPU(True).setForceGPU(True) Ensure that batch_size is set to appropriate value (for example: 64)
Single-node multi-GPU execution (similar to Caffe with solver_mode: GPU) lenet.set(train_algo="allreduce_parallel_batches", test_algo="minibatch", parallel_batches=num_gpu).setGPU(True).setForceGPU(True) Ensure that batch_size is set to appropriate value (for example: 64)
Distributed prediction lenet.set(test_algo="allreduce")  
Distributed synchronous training lenet.set(train_algo="allreduce_parallel_batches", parallel_batches=num_cluster_cores) Ensure that batch_size is set to appropriate value (for example: 64)

Saving the trained model, y_train)'trained_weights')
new_lenet = Caffe2DML(spark, solver='lenet_solver.proto', input_shape=(1, 28, 28))
new_lenet.score(X_test, y_test)

Loading a pretrained caffemodel

We provide a converter utility to convert .caffemodel trained using Caffe to SystemML format.

# First download deploy file and caffemodel
import urllib
urllib.urlretrieve('', 'VGG_ILSVRC_19_layers_deploy.proto')
urllib.urlretrieve('', 'VGG_ILSVRC_19_layers.caffemodel')
# Save the weights into trained_vgg_weights directory
import systemml as sml
sml.convert_caffemodel(sc, 'VGG_ILSVRC_19_layers_deploy.proto', 'VGG_ILSVRC_19_layers.caffemodel',  'trained_vgg_weights')

We can then use the trained_vgg_weights directory for performing prediction or fine-tuning.

# Download the VGG network
urllib.urlretrieve('', 'VGG_ILSVRC_19_layers_network.proto')
urllib.urlretrieve('', 'VGG_ILSVRC_19_layers_solver.proto')
# Storing the labels.txt in the weights directory allows predict to return a label (for example: 'cougar, puma, catamount, mountain lion, painter, panther, Felis concolor') rather than the column index of one-hot encoded vector (for example: 287).
urllib.urlretrieve('', os.path.join('trained_vgg_weights', 'labels.txt'))
from systemml.mllearn import Caffe2DML
vgg = Caffe2DML(sqlCtx, solver='VGG_ILSVRC_19_layers_solver.proto', input_shape=(3, 224, 224))
# We can then perform prediction:
from PIL import Image
X_test = sml.convertImageToNumPyArr('test.jpg'), img_shape=(3, 224, 224))
# OR Fine-Tuning:, y_train)

Please see Caffe2DML’s reference guide for more details.