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lib/AI/MXNet/KVStore.pm  view on Meta::CPAN

package AI::MXNet::KVStore;
use strict;
use warnings;
use AI::MXNet::Base;
use AI::MXNet::NDArray;
use AI::MXNet::Optimizer;
use MIME::Base64;
use Storable;
use Mouse;
use AI::MXNet::Function::Parameters;

=head1 NAME

    AI::MXNet::KVStore - Key value store interface of MXNet.

=head1 DESCRIPTION 

    Key value store interface of MXNet for parameter synchronization, over multiple devices.
=cut

has 'handle' => (is => 'ro', isa => 'KVStoreHandle', required => 1);
has '_updater' => (is => 'rw',  isa => 'AI::MXNet::Updater');
has '_updater_func' => (is => 'rw', isa => 'CodeRef');

sub DEMOLISH
{
    check_call(AI::MXNetCAPI::KVStoreFree(shift->handle));
}

=head2  init

    Initialize a single or a sequence of key-value pairs into the store.
    For each key, one must init it before push and pull.
    Only worker 0's (rank == 0) data are used.
    This function returns after data have been initialized successfully

    Parameters
    ----------
    key : str or an array ref of str
        The keys.
    value : NDArray or an array ref of NDArray objects
        The values.

    Examples
    --------
    >>> # init a single key-value pair
    >>> $shape = [2,3]
    >>> $kv = mx->kv->create('local')
    >>> $kv->init(3, mx->nd->ones($shape)*2)
    >>> $a = mx->nd->zeros($shape)
    >>> $kv->pull(3, out=>$a)
    >>> print $a->aspdl
    [[ 2  2  2]
    [ 2  2  2]]

    >>> # init a list of key-value pairs
    >>> $keys = [5, 7, 9]
    >>> $kv->init(keys, [map { mx->nd->ones($shape) } 0..@$keys-1])
=cut

method init(
    Str|ArrayRef[Str] $key,
    AI::MXNet::NDArray|ArrayRef[AI::MXNet::NDArray]|ArrayRef[ArrayRef[AI::MXNet::NDArray]] $value
)
{
    my ($keys, $vals) = _key_value($key, $value);
    check_call(
        AI::MXNetCAPI::KVStoreInitEx(
            $self->handle, scalar(@{ $keys }), $keys, $vals
        )
    );
}

=head2  push

    Push a single or a sequence of key-value pairs into the store.
    Data consistency:
    1. this function returns after adding an operator to the engine.
    2. push is always called after all previous push and pull on the same
        key are finished.
    3. there is no synchronization between workers. One can use _barrier()
    to sync all workers.

    Parameters
    ----------
    key : str or array ref of str
    value : NDArray or array ref of NDArray or array ref of array refs of NDArray
    priority : int, optional
        The priority of the push operation.
        The higher the priority, the faster this action is likely
        to be executed before other push actions.

    Examples
    --------
    >>> # push a single key-value pair
    >>> $kv->push(3, mx->nd->ones($shape)*8)
    >>> $kv->pull(3, out=>$a) # pull out the value
    >>> print $a->aspdl()
        [[ 8.  8.  8.]
        [ 8.  8.  8.]]

    >>> # aggregate the value and the push
    >>> $gpus = [map { mx->gpu($_) } 0..3]
    >>> $b = [map { mx->nd->ones($shape, ctx => $_) } @$gpus]
    >>> $kv->push(3, $b)
    >>> $kv->pull(3, out=>$a)
    >>> print $a->aspdl
        [[ 4.  4.  4.]
        [ 4.  4.  4.]]

    >>> # push a list of keys.
    >>> # single device
    >>> $kv->push($keys, [map { mx->nd->ones($shape) } 0..@$keys-1)
    >>> $b = [map { mx->nd->zeros(shape) } 0..@$keys-1]
    >>> $kv->pull($keys, out=>$b)
    >>> print $b->[1]->aspdl
        [[ 1.  1.  1.]
        [ 1.  1.  1.]]

    >>> # multiple devices:
    >>> $b = [map { [map { mx->nd->ones($shape, ctx => $_) } @$gpus] } @$keys-1]
    >>> $kv->push($keys, $b)
    >>> $kv->pull($keys, out=>$b)
    >>> print $b->[1][1]->aspdl()
        [[ 4.  4.  4.]
        [ 4.  4.  4.]]
=cut

method push(
    Str|ArrayRef[Str] $key,
    AI::MXNet::NDArray|ArrayRef[AI::MXNet::NDArray]|ArrayRef[ArrayRef[AI::MXNet::NDArray]] $value,
    Int :$priority=0
)
{
    my ($keys, $vals) = _key_value($key, $value);
    check_call(
        AI::MXNetCAPI::KVStorePushEx(
            $self->handle, scalar(@{ $keys }), $keys, $vals, $priority
        )
    );
}