minibatchpredict - Mini-batched neural network prediction - MATLAB (original) (raw)
Main Content
Mini-batched neural network prediction
Since R2024a
Syntax
Description
[[Y1,...,YM](#mw%5F08caf790-7982-4b6b-9d57-16229d31902c)] = minibatchpredict([net](#mw%5Fc7ae5ad7-5485-4270-8657-694ab264fb57%5Fsep%5Fmw%5F3ffb42b3-6af7-4c22-82b3-4fb0f6a399f2),[images](#mw%5Fb415c7c0-efa9-4077-888a-cb807315d017))
makes neural network predictions by looping over mini-batches of the specified images, whereM
is the number of network outputs.
[[Y1,...,YM](#mw%5F08caf790-7982-4b6b-9d57-16229d31902c)] = minibatchpredict([net](#mw%5Fc7ae5ad7-5485-4270-8657-694ab264fb57%5Fsep%5Fmw%5F3ffb42b3-6af7-4c22-82b3-4fb0f6a399f2),[sequences](#mw%5Fd0a7ae26-3433-4960-badb-1336cd8c81aa))
makes neural network predictions by looping over mini-batches of the specified sequences.
[[Y1,...,YM](#mw%5F08caf790-7982-4b6b-9d57-16229d31902c)] = minibatchpredict([net](#mw%5Fc7ae5ad7-5485-4270-8657-694ab264fb57%5Fsep%5Fmw%5F3ffb42b3-6af7-4c22-82b3-4fb0f6a399f2),[features](#mw%5Ff5af1860-6a3f-4ae6-b9d2-22d602106b60))
makes neural network predictions by looping over mini-batches of the specified feature or tabular data.
[[Y1,...,YM](#mw%5F08caf790-7982-4b6b-9d57-16229d31902c)] = minibatchpredict([net](#mw%5Fc7ae5ad7-5485-4270-8657-694ab264fb57%5Fsep%5Fmw%5F3ffb42b3-6af7-4c22-82b3-4fb0f6a399f2),[data](#mw%5Fa2532343-aac5-47aa-81d4-f32987abe7a9))
makes neural network predictions by looping over mini-batches of other layouts or combinations of data.
[[Y1,...,YM](#mw%5F08caf790-7982-4b6b-9d57-16229d31902c)] = minibatchpredict([net](#mw%5Fc7ae5ad7-5485-4270-8657-694ab264fb57%5Fsep%5Fmw%5F3ffb42b3-6af7-4c22-82b3-4fb0f6a399f2),[X1,...,XN](#mw%5F7d327b88-3b20-47f9-b11b-ea2632d38241))
makes neural network predictions for a network with multiple inputs using the specified in-memory data.
[[Y1,...,YM](#mw%5F08caf790-7982-4b6b-9d57-16229d31902c)] = minibatchpredict(___,[Name=Value](#namevaluepairarguments))
specifies additional options using one or more name-value arguments. For example,MiniBatchSize=32
makes predictions by looping over mini-batches of size 32.
Examples
Make Predictions Using dlnetwork
Object
This example shows how to make predictions using a dlnetwork
object by looping over mini-batches.
For large data sets, or when predicting on hardware with limited memory, make predictions by looping over mini-batches of the data using the minibatchpredict
function.
Load dlnetwork
Object
Load a trained dlnetwork
object and the corresponding class names into the workspace. The neural network has one input and two outputs. It takes images of handwritten digits as input, and predicts the digit label and angle of rotation.
Load Data for Prediction
Load the digits test data for prediction.
View the class names.
classNames = 10x1 cell {'0'} {'1'} {'2'} {'3'} {'4'} {'5'} {'6'} {'7'} {'8'} {'9'}
View some of the images and the corresponding labels and angles of rotation.
numObservations = size(XTest,4); numPlots = 9; idx = randperm(numObservations,numPlots);
figure for i = 1:numPlots nexttile(i) I = XTest(:,:,:,idx(i)); label = labelsTest(idx(i)); imshow(I) title("Label: " + string(label) + newline + "Angle: " + anglesTest(idx(i))) end
Make Predictions
Make predictions using the minibatchpredict function, and convert the classification scores to labels using the scores2label function. By default, the minibatchpredict
function uses a GPU if one is available. Using a GPU requires a Parallel Computing Toolbox™ license and a supported GPU device. For information on supported devices, see GPU Computing Requirements (Parallel Computing Toolbox). Otherwise, the function uses the CPU. To select the execution environment manually, use the ExecutionEnvironment
argument of the minibatchpredict
function.
[scoresTest,Y2Test] = minibatchpredict(net,XTest); Y1Test = scores2label(scoresTest,classNames);
Visualize some of the predictions.
idx = randperm(numObservations,numPlots);
figure for i = 1:numPlots nexttile(i) I = XTest(:,:,:,idx(i)); label = Y1Test(idx(i)); imshow(I) title("Label: " + string(label) + newline + "Angle: " + Y2Test(idx(i))) end
Input Arguments
net
— Neural network
dlnetwork
object
Neural network, specified as a dlnetwork object.
images
— Image data
numeric array | dlarray
object | datastore | minibatchqueue
object
Image data, specified as a numeric array, dlarray
object, datastore, or minibatchqueue
object.
Tip
For sequences of images, such as video data, use thesequences input argument, instead.
If you have data that fits in memory that does not require additional processing, then specifying the input data as a numeric array is usually the easiest option. If you want to make predictions with image files stored on your system, or want to apply additional processing, then datastores are usually the easiest option.
Tip
Neural networks expect input data with a specific layout. For example, image classification networks typically expect image representations to be_h_-by-_w_-by-c numeric arrays, where h, w, and c are the height, width, and number of channels of the images, respectively. Most neural networks have an input layer that specifies the expected layout of the data.
Most datastores and functions output data in the layout that the network expects. If your data is in a different layout than what the network expects, then indicate that your data has a different layout by using the InputDataFormats
argument or by specifying input data as a formatted dlarray
object. Adjusting the InputDataFormats
argument is usually easier than preprocessing the input data.
For neural networks that do not have input layers, you must use theInputDataFormats
argument or use formatteddlarray
objects.
For more information, see Deep Learning Data Formats.
Numeric Array or dlarray
Object
For data that fits in memory and does not require additional processing, you can specify a data set of images as a numeric array or a dlarray
object.
The layouts of numeric arrays and unformatted dlarray
objects depend on the type of image data, and must be consistent with theInputDataFormats
argument.
Most networks expect image data in these layouts:
Data | Layout |
---|---|
2-D images | _h_-by-_w_-by-_c_-by-N array, where h, w, and c are the height, width, and number of channels of the images, respectively, and N is the number of images.Data in this layout has the data format "SSCB" (spatial, spatial, channel, batch). |
3-D images | _h_-by-_w_-by-_d_-by-_c_-by-N array, where h, w, d, and c are the height, width, depth, and number of channels of the images, respectively, and N is the number of images.Data in this layout has the data format "SSSCB" (spatial, spatial, spatial, channel, batch). |
For data in a different layout, indicate that your data has a different layout by using the InputDataFormats
argument or use a formatteddlarray
object. For more information, see Deep Learning Data Formats.
Datastore
Datastores read batches of images and targets. Use datastores when you have data that does not fit in memory, or when you want to apply transformations to the data.
For image data, the minibatchpredict
function supports these datastores:
Datastore | Description | Example Usage |
---|---|---|
ImageDatastore | Datastore of images saved on disk. | Make predictions with images saved on your system, where the images are the same size. When the images are different sizes, use anaugmentedImageDatastore object. |
augmentedImageDatastore | Datastore that applies random affine geometric transformations, including resizing. | Make predictions with images saved on disk, where the images are different sizes.When you make predictions using an augmented image datastore, do not apply additional augmentations such as rotation, reflection, shear, and translation. |
TransformedDatastore | Datastore that transforms batches of data read from an underlying datastore using a custom transformation function. | Transform datastores with outputs not supported by theminibatchpredict function.Apply custom transformations to datastore output. |
CombinedDatastore | Datastore that reads from two or more underlying datastores. | Make predictions using a network with multiple inputs. |
Custom mini-batch datastore | Custom datastore that returns mini-batches of data. | Make predictions using data in a layout that other datastores do not support.For details, see Develop Custom Mini-Batch Datastore. |
Tip
ImageDatastore
objects allow batch reading of JPG or PNG image files using prefetching. For efficient preprocessing of images for deep learning, including image resizing, use an augmentedImageDatastore object. Do not use the ReadFcn
property of ImageDatastore
objects. If you set the ReadFcn
property to a custom function, then the ImageDatastore
object does not prefetch image files and is usually significantly slower.
You can use other built-in datastores for testing deep learning neural networks by using the transform and combine functions. These functions can convert the data read from datastores to the layout required by the minibatchpredict
function. The required layout of the datastore output depends on the neural network architecture. For more information, see Datastore Customization.
minibatchqueue
Object
For greater control over how the software processes and transforms mini-batches, you can specify data as a minibatchqueue object.
If you specify data as a minibatchqueue
object, then theminibatchpredict
function ignores the MiniBatchSize
property of the object and uses the MiniBatchSize argument instead. For minibatchqueue
input, thePreprocessingEnvironment
property must be"serial"
.
Note
This argument supports complex-valued predictors.
sequences
— Sequence or time series data
cell array of numeric arrays | cell array of dlarray
objects | numeric array | dlarray
object | datastore | minibatchqueue
object
Sequence or time series data, specified as a numeric array, cell array of numeric arrays, dlarray
object, cell array of dlarray
objects, datastore, or minibatchqueue
object.
If you have sequences of the same length that fit in memory and do not require additional processing, then specifying the input data as a numeric array is usually the easiest option. If you have sequences of different lengths that fit in memory and do not require additional processing, then specifying the input data as a cell array of numeric arrays is usually the easiest option. If you want to train with sequences stored on your system, or want to apply additional processing such as custom transformations, then datastores are usually the easiest option.
Tip
Neural networks expect input data with a specific layout. For example, vector-sequence classification networks typically expect a vector-sequence representations to be_t_-by-c arrays, where t and_c_ are the number of time steps and channels of sequences, respectively. Neural networks typically have an input layer that specifies the expected layout of the data.
Most datastores and functions output data in the layout that the network expects. If your data is in a different layout than what the network expects, then indicate that your data has a different layout by using the InputDataFormats
argument or by specifying input data as a formatted dlarray
object. Adjusting the InputDataFormats
argument is usually easier than preprocessing the input data.
For neural networks that do not have input layers, you must use theInputDataFormats
argument or use formatteddlarray
objects.
For more information, see Deep Learning Data Formats.
Numeric Array, dlarray
Object, or Cell Array
For data that fits in memory and does not require additional processing like custom transformations, you can specify a single sequence as a numeric array ordlarray
object or a data set of sequences as a cell array of numeric arrays, or dlarray
objects.
For cell array input, the cell array must be an_N_-by-1 cell array of numeric arrays or dlarray
objects, where N is the number of observations. The sizes and shapes of the numeric arrays or dlarray
objects that represent the sequences depend on the type of sequence data, and must be consistent with theInputDataFormats
argument value.
This table describes the expected layout of data for a neural network with a sequence input layer.
Data | Layout |
---|---|
Vector sequences | _s_-by-c matrices, where s and c are the numbers of time steps and channels (features) of the sequences, respectively. |
1-D image sequences | _h_-by-_c_-by-s arrays, where h and c correspond to the height and number of channels of the images, respectively, and s is the sequence length. |
2-D image sequences | _h_-by-_w_-by-_c_-by-s arrays, where h, w, and c correspond to the height, width, and number of channels of the images, respectively, and s is the sequence length. |
3-D image sequences | _h_-by-_w_-by-_d_-by-_c_-by-s, where h, w, d, and c correspond to the height, width, depth, and number of channels of the 3-D images, respectively, and s is the sequence length. |
For data in a different layout, indicate that your data has a different layout by using the InputDataFormats
argument or use a formatteddlarray
object. For more information, see Deep Learning Data Formats.
Datastore
Datastores read batches of sequences and targets. Use datastores when you have data that does not fit in memory, or when you want to apply transformations to the data.
For sequence and time-series data, the minibatchpredict
function supports these datastores:
Datastore | Description | Example Usage |
---|---|---|
TransformedDatastore | Datastore that transforms batches of data read from an underlying datastore using a custom transformation function. | Transform datastores with outputs not supported by theminibatchpredict function.Apply custom transformations to datastore output. |
CombinedDatastore | Datastore that reads from two or more underlying datastores. | Make predictions using a network with multiple inputs. |
Custom mini-batch datastore | Custom datastore that returns mini-batches of data. | Train neural network using data in a layout that other datastores do not support.For details, see Develop Custom Mini-Batch Datastore. |
You can use other built-in datastores by using the transform andcombine functions. These functions can convert the data read from datastores to the layout required by the minibatchpredict
function. For example, you can transform and combine data read from in-memory arrays and CSV files using ArrayDatastore
andTabularTextDatastore
objects, respectively. The required layout of the datastore output depends on the neural network architecture. For more information, see Datastore Customization.
minibatchqueue
Object
For greater control over how the software processes and transforms mini-batches, you can specify data as a minibatchqueue object.
If you specify data as a minibatchqueue
object, then theminibatchpredict
function ignores the MiniBatchSize
property of the object and uses the MiniBatchSize argument instead. For minibatchqueue
input, thePreprocessingEnvironment
property must be"serial"
.
Note
This argument supports complex-valued predictors.
features
— Feature or tabular data
numeric array | dlarray
object | table | datastore | minibatchqueue
object
Feature or tabular data, specified as a numeric array, datastore, table, orminibatchqueue
object.
If you have data that fits in memory that does not require additional processing, then specifying the input data as a numeric array or table is usually the easiest option. If you want to train with feature or tabular data stored on your system, or want to apply additional processing such as custom transformations, then datastores are usually the easiest option.
Tip
Neural networks expect input data with a specific layout. For example feature classification networks typically expect feature and tabular data representations to be 1-by-c vectors, where c is the number features of the data. Neural networks typically have an input layer that specifies the expected layout of the data.
Most datastores and functions output data in the layout that the network expects. If your data is in a different layout than what the network expects, then indicate that your data has a different layout by using the InputDataFormats
argument or by specifying input data as a formatted dlarray
object. Adjusting the InputDataFormats
argument is usually easier than preprocessing the input data.
For neural networks that do not have input layers, you must use theInputDataFormats
argument or use formatteddlarray
objects.
For more information, see Deep Learning Data Formats.
Numeric Array or dlarray
Objects
For feature data that fits in memory and does not require additional processing like custom transformations, you can specify feature data as a numeric array ordlarray
object.
The layouts of numeric arrays and unformatted dlarray
objects must be consistent with the InputDataFormats
argument. Most networks with feature input expect input data specified as annumObservations
-by-numFeatures
array, wherenumObservations
is the number of observations andnumFeatures
is the number of features of the input data.
Table
For feature data that fits in memory and does not require additional processing like custom transformations, you can specify feature data as a table.
To specify feature data as a table, specify a table withnumObservations
rows and numFeatures+1
columns, where numObservations
and numFeatures
are the number of observations and channels of the input data, respectively. Theminibatchpredict
function uses the firstnumFeatures
columns as the input features and uses the last column as the targets.
Datastore
Datastores read batches of feature data and targets. Use datastores when you have data that does not fit in memory, or when you want to apply transformations to the data.
For feature and tabular data, the minibatchpredict
function supports these datastores:
Data Type | Description | Example Usage |
---|---|---|
TransformedDatastore | Datastore that transforms batches of data read from an underlying datastore using a custom transformation function. | Make predictions using a neural network with multiple inputs.Transform datastores with outputs not supported by thetrainnet function.Apply custom transformations to datastore output. |
CombinedDatastore | Datastore that reads from two or more underlying datastores. | Make predictions using a neural network with multiple inputs. |
Custom mini-batch datastore | Custom datastore that returns mini-batches of data. | Make predictions using data in a layout that other datastores do not support.For details, see Develop Custom Mini-Batch Datastore. |
You can use other built-in datastores for making predictions by using the transform andcombine functions. These functions can convert the data read from datastores to the table or cell array format required by the minibatchpredict
function. For more information, see Datastore Customization.
minibatchqueue
Object
For greater control over how the software processes and transforms mini-batches, you can specify data as a minibatchqueue object.
If you specify data as a minibatchqueue
object, then theminibatchpredict
function ignores the MiniBatchSize
property of the object and uses the MiniBatchSize argument instead. For minibatchqueue
input, thePreprocessingEnvironment
property must be"serial"
.
Note
This argument supports complex-valued predictors.
data
— Generic data or combinations of data types
numeric array | dlarray
object | datastore | minibatchqueue
object
Generic data or combinations of data types, specified as a numeric array,dlarray
object, datastore, or minibatchqueue
object.
If you have data that fits in memory and does not require additional processing, then specifying the input data as a numeric array is usually easiest option. If you want to train with data stored on your system, or you want to apply additional processing, then using datastores it is usually easiest option.
Tip
Neural networks expect input data with a specific layout. For example, vector-sequence classification networks typically expect a vector-sequence representations to be_t_-by-c arrays, where t and_c_ are the number of time steps and channels of sequences, respectively. Neural networks typically have an input layer that specifies the expected layout of the data.
Most datastores and functions output data in the layout that the network expects. If your data is in a different layout than what the network expects, then indicate that your data has a different layout by using the InputDataFormats
argument or by specifying input data as a formatted dlarray
object. Adjusting the InputDataFormats
argument is usually easier than preprocessing the input data.
For neural networks that do not have input layers, you must use theInputDataFormats
argument or use formatteddlarray
objects.
For more information, see Deep Learning Data Formats.
Numeric or dlarray
Objects
For data that fits in memory and does not require additional processing like custom transformations, you can specify feature data as a numeric array.
For a neural network with an inputLayer
object, the expected layout of input data is a given by the InputFormat
property of the layer.
For data in a different layout, indicate that your data has a different layout by using the InputDataFormats
argument or use a formatteddlarray
object. For more information, see Deep Learning Data Formats.
Datastores
Datastores read batches of data and targets. Use datastores when you have data that does not fit in memory, or when you want to apply transformations to the data.
Generic data or combinations of data types, theminibatchpredict
function supports these datastores:
Data Type | Description | Example Usage |
---|---|---|
TransformedDatastore | Datastore that transforms batches of data read from an underlying datastore using a custom transformation function. | Make predictions using a neural network with multiple inputs.Transform outputs of datastores not supported byminibatchpredict to the have the required format.Apply custom transformations to datastore output. |
CombinedDatastore | Datastore that reads from two or more underlying datastores. | Make predictions using a neural network with multiple inputs. |
Custom mini-batch datastore | Custom datastore that returns mini-batches of data. | Make predictions using data in a format that other datastores do not support.For details, see Develop Custom Mini-Batch Datastore. |
You can use other built-in datastores by using the transform andcombine functions. These functions can convert the data read from datastores to the table or cell array format required by minibatchpredict
. For more information, see Datastore Customization.
minibatchqueue
Object
For greater control over how the software processes and transforms mini-batches, you can specify data as a minibatchqueue object.
If you specify data as a minibatchqueue
object, then theminibatchpredict
function ignores the MiniBatchSize
property of the object and uses the MiniBatchSize argument instead. For minibatchqueue
input, thePreprocessingEnvironment
property must be"serial"
.
Note
This argument supports complex-valued predictors.
X1,...,XN
— In-memory data for neural network with multiple inputs
numeric array | dlarray
object | cell array
In-memory data for a neural network with multiple inputs, specified as numeric arrays, dlarray
objects, or cell arrays.
For a neural network with multiple inputs, if you have data that fits in memory and does not require additional processing, then specifying the input data as in-memory arrays is usually the easiest option. If you want to make predictions with data stored on your system, or you want to apply additional processing, then using datastores is usually the easiest option.
Tip
Neural networks expect input data with a specific layout. For example, vector-sequence classification networks typically expect a vector-sequence representations to be_t_-by-c arrays, where t and_c_ are the number of time steps and channels of sequences, respectively. Neural networks typically have an input layer that specifies the expected layout of the data.
Most datastores and functions output data in the layout that the network expects. If your data is in a different layout than what the network expects, then indicate that your data has a different layout by using the InputDataFormats
argument or by specifying input data as a formatted dlarray
object. Adjusting the InputDataFormats
argument is usually easier than preprocessing the input data.
For neural networks that do not have input layers, you must use theInputDataFormats
argument or use formatteddlarray
objects.
For more information, see Deep Learning Data Formats.
For each input X1,...,XN
, where N
is the number of inputs, specify the data as a numeric array, dlarray
object, or cell array as described by the argument images,sequences, features, ordata that matches the type of data. The inputXi
corresponds to the network inputnet.InputNames(i)
.
Note
This argument supports complex-valued predictors.
Name-Value Arguments
Specify optional pairs of arguments asName1=Value1,...,NameN=ValueN
, where Name
is the argument name and Value
is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.
Example: minibatchpredict(net,images,MiniBatchSize=32)
makes predictions by looping over images
using mini-batches of size 32.
MiniBatchSize
— Size of mini-batches
128
(default) | positive integer
Size of mini-batches to use for prediction, specified as a positive integer. Larger mini-batch sizes require more memory, but can lead to faster predictions.
When you make predictions with sequences of different lengths, the mini-batch size can impact the amount of padding added to the input data, which can result in different predicted values. Try using different values to see which works best with your network. To specify padding options, use the SequenceLength arguments.
Note
If you specify the input data as a minibatchqueue
object, then the minibatchpredict
function uses the mini-batch size specified by this argument and not the MiniBatchSize
property of theminibatchqueue
object.
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
Outputs
— Layers to extract outputs from
string array | cell array of character vectors
Layers to extract outputs from, specified as a string array or a cell array of character vectors containing the layer names.
- If
Outputs(i)
corresponds to a layer with a single output, thenOutputs(i)
is the name of the layer. - If
Outputs(i)
corresponds to a layer with multiple outputs, thenOutputs(i)
is the layer name followed by the/
character and the name of the layer output:"layerName/outputName"
.
The default value is net.OutputNames
.
Acceleration
— Performance optimization
"auto"
(default) | "mex"
| "none"
Performance optimization, specified as one of these values:
"auto"
— Automatically apply a number of optimizations suitable for the input network and hardware resources."mex"
— Compile and execute a MEX function. This option is available only when using a GPU. You must store the input data or the network learnable parameters asgpuArray
objects. Using a GPU requires Parallel Computing Toolbox™ and a supported GPU device. For information on supported devices, see GPU Computing Requirements (Parallel Computing Toolbox). If Parallel Computing Toolbox or a suitable GPU is not available, then the software returns an error."none"
— Disable all acceleration.
When you use the "auto"
or "mex"
option, the software can offer performance benefits at the expense of an increased initial run time. Subsequent calls to the function are typically faster. Use performance optimization when you call the function multiple times using different input data.
When Acceleration
is "mex"
, the software generates and executes a MEX function based on the model and parameters you specify in the function call. A single model can have several associated MEX functions at one time. Clearing the model variable also clears any MEX functions associated with that model.
When Acceleration
is"auto"
, the software does not generate a MEX function.
The "mex"
option is available only when you use a GPU. You must have a C/C++ compiler installed and the GPU Coder™ Interface for Deep Learning support package. Install the support package using the Add-On Explorer in MATLAB®. For setup instructions, see MEX Setup (GPU Coder). GPU Coder is not required.
The "mex"
option has these limitations:
- Only the
single
precision data type is supported. The input data or the network learnable parameters must have the underlying data typesingle
. - Networks with inputs that are not connected to an input layer are not supported.
- Traced dlarray objects are not supported. This means that the
"mex"
option is not supported inside a call to the dlfeval function. - Not all layers are supported. For a list of supported layers, see Supported Layers (GPU Coder).
- MATLAB Compiler™ does not support deploying your network when using the
"mex"
option.
For quantized networks, the "mex"
option requires a CUDA® enabled NVIDIA® GPU with compute capability 6.1, 6.3, or higher.
ExecutionEnvironment
— Hardware resource
"auto"
(default) | "gpu"
| "cpu"
Hardware resource, specified as one of these values:
"auto"
— Use a GPU if one is available. Otherwise, use the CPU. Ifnet
is a quantized network with theTargetLibrary
property set to"none"
, use the CPU even if a GPU is available."gpu"
— Use the GPU. Using a GPU requires a Parallel Computing Toolbox license and a supported GPU device. For information about supported devices, seeGPU Computing Requirements (Parallel Computing Toolbox). If Parallel Computing Toolbox or a suitable GPU is not available, then the software returns an error."cpu"
— Use the CPU.
SequenceLength
— Option to pad or truncate input sequences
"longest"
(default) | "shortest"
Option to pad or truncate the input sequences, specified as one of these options:
"longest"
— Pad sequences to have the same length as the longest sequence. This option does not discard any data, though padding can introduce noise to the neural network."shortest"
— Truncate sequences to have the same length as the shortest sequence. This option ensures that the function does not add padding, at the cost of discarding data.
To learn more about the effects of padding and truncating the input sequences, seeSequence Padding and Truncation.
SequencePaddingDirection
— Direction of padding or truncation
"right"
(default) | "left"
Direction of padding or truncation, specified as one of these options:
"right"
— Pad or truncate sequences on the right. The sequences start at the same time step and the software truncates or adds padding to the end of each sequence."left"
— Pad or truncate sequences on the left. The software truncates or adds padding to the start of each sequence so that the sequences end at the same time step.
Because recurrent layers process sequence data one time step at a time, when the recurrent layer OutputMode
property is "last"
, any padding in the final time steps can negatively influence the layer output. To pad or truncate sequence data on the left, set the SequencePaddingDirection argument to "left"
.
For sequence-to-sequence neural networks (when the OutputMode
property is"sequence"
for each recurrent layer), any padding in the first time steps can negatively influence the predictions for the earlier time steps. To pad or truncate sequence data on the right, set the SequencePaddingDirection option to "right"
.
To learn more about the effects of padding and truncating sequences, see Sequence Padding and Truncation.
SequencePaddingValue
— Value by which to pad input sequences
0
(default) | scalar
Value by which to pad the input sequences, specified as a scalar.
Do not pad sequences with NaN
, because doing so can propagate errors through the neural network.
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
InputDataFormats
— Description of input data dimensions
"auto"
(default) | string array | cell array of character vectors | character vector
Description of the input data dimensions, specified as a string array, character vector, or cell array of character vectors.
If the InputDataFormats
argument value is "auto"
, then the software uses the formats expected by the network input. Otherwise, the software uses the specified formats for the corresponding network input.
A data format is a string of characters, where each character describes the type of the corresponding data dimension.
The characters are:
"S"
— Spatial"C"
— Channel"B"
— Batch"T"
— Time"U"
— Unspecified
For example, consider an array containing a batch of sequences where the first, second, and third dimensions correspond to channels, observations, and time steps, respectively. You can specify that this array has the format "CBT"
(channel, batch, time).
You can specify multiple dimensions labeled "S"
or "U"
. You can use the labels "C"
, "B"
, and"T"
once each, at most. The software ignores singleton trailing"U"
dimensions after the second dimension.
For a neural network with multiple inputs, net
, specify an array of input data formats, where InputDataFormats(i)
corresponds to the input net.InputNames(i)
.
For more information, see Deep Learning Data Formats.
Data Types: char
| string
| cell
OutputDataFormats
— Description of output data dimensions
"auto"
(default) | string array | cell array of character vectors | character vector
Description of the output data dimensions, specified as one of these values:
"auto"
— If the output data has the same number of dimensions as the input data, then theminibatchpredict
function uses the format specified byInputDataFormats
. If the output data has a different number of dimensions than the input data, then theminibatchpredict
function automatically permutes the dimensions of the output data so that they are consistent with the network input layers or theInputDataFormats
value.- String, character vector, or cell array of character vectors — The
minibatchpredict
function uses the specified data formats.
A data format is a string of characters, where each character describes the type of the corresponding data dimension.
The characters are:
"S"
— Spatial"C"
— Channel"B"
— Batch"T"
— Time"U"
— Unspecified
For example, consider an array containing a batch of sequences where the first, second, and third dimensions correspond to channels, observations, and time steps, respectively. You can specify that this array has the format "CBT"
(channel, batch, time).
You can specify multiple dimensions labeled "S"
or "U"
. You can use the labels "C"
, "B"
, and"T"
once each, at most. The software ignores singleton trailing"U"
dimensions after the second dimension.
For more information, see Deep Learning Data Formats.
Data Types: char
| string
| cell
UniformOutput
— Flag to return padded data as uniform array
true
or 1
(default) | false
or 0
Flag to return padded data as a uniform array, specified as a logical1
(true
) or 0
(false
). When you set the value to 0
, the software outputs a cell array of predictions.
Output Arguments
Y1,...,YM
— Neural network predictions
numeric array | dlarray
object | cell array
Neural network predictions, returned as numeric arrays, dlarray
objects, or cell arrays Y1,...,YM
, where M
is the number of network outputs.
The predictions Yi
correspond to the outputOutputs(i)
.
More About
Floating-Point Arithmetic
The minibatchpredict
function converts integer numeric array and datastore inputs to single precision floating point values. Forminibatchqueue
inputs, the software uses the data type specified by theOutputCast
property of that input.
When you use prediction or validation functions with a dlnetwork
object with single-precision learnable and state parameters, the software performs the computations using single-precision, floating-point arithmetic.
When you use prediction or validation functions with a dlnetwork
object with double-precision learnable and state parameters:
- If the input data is single precision, the software performs the computations using single-precision, floating-point arithmetic.
- If the input data is double precision, the software performs the computations using double-precision, floating-point arithmetic.
Reproducibility
To provide the best performance, deep learning using a GPU in MATLAB is not guaranteed to be deterministic. Depending on your network architecture, under some conditions you might get different results when using a GPU to train two identical networks or make two predictions using the same network and data. If you require determinism when performing deep learning operations using a GPU, use the deep.gpu.deterministicAlgorithms function (since R2024b).
If you use the rng function to set the same random number generator and seed, then predictions made using the CPU are reproducible.
Extended Capabilities
GPU Arrays
Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.
This function fully supports GPU acceleration.
By default, the minibatchpredict
function uses a GPU if one is available. You can specify the hardware that the minibatchpredict
function uses by specifying the ExecutionEnvironment name-value argument.
For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).
Version History
Introduced in R2024a