cavis/libnd4j/include/ops/declarable/helpers/cuda/sru.cu

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/*******************************************************************************
* Copyright (c) 2015-2018 Skymind, Inc.
*
* This program and the accompanying materials are made available under the
* terms of the Apache License, Version 2.0 which is available at
* https://www.apache.org/licenses/LICENSE-2.0.
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
* SPDX-License-Identifier: Apache-2.0
******************************************************************************/
//
// implementation of operations for Simple Recurrent Unit: arXiv:1709.02755v2 [cs.CL] 12 Sep 2017
//
// @author Yurii Shyrma, created on 05.12.2017
//
#include<ops/declarable/helpers/sru.h>
#include <NDArrayFactory.h>
namespace nd4j {
namespace ops {
namespace helpers {
//////////////////////////////////////////////////////////////////////////
static FORCEINLINE NDArray activation(const NDArray& arr) {
// return (const_cast<NDArray<T>&>(arr)).template transform<simdOps::Tanh<T>>();
auto result = NDArray(&arr, false, arr.getContext());
(const_cast<NDArray&>(arr)).applyTransform(transform::Tanh, &result);
return result;
}
//////////////////////////////////////////////////////////////////////////
static FORCEINLINE NDArray sigmoid(const NDArray& arr) {
return (const_cast<NDArray&>(arr)).transform(transform::Sigmoid);
}
//////////////////////////////////////////////////////////////////////////
void sruCell(nd4j::LaunchContext * context, const NDArray* x, const NDArray* c0, const NDArray* w, const NDArray* b, NDArray* h, NDArray* c) {
// x input [bS x inSize], bS - batch size, inSize - number of features
// c0 previous cell state c [bS x inSize], that is at previous time step t-1
// w weights [inSize x 3*inSize]
// b biases [2*inSize]
// h current cell output [bS x inSize], that is at current time step t
// c current cell state [bS x inSize], that is at current time step t
const int inSize = x->sizeAt(1); // inSize - number of features
auto z = mmul(*x, *w); // [bS x 3*inSize]
// forget gate = sigmoid(x*Wf + bf)
auto f = sigmoid(z({0,0, inSize, 2*inSize}) + (*b)({0, inSize}));
// reset gate = sigmoid(x*Wr + br)
auto r = sigmoid(z({0,0, 2*inSize, 3*inSize}) + (*b)({inSize, 2*inSize}));
// ◦ means element-wise product or so called Hadamard product
// current sell state = f◦c0 + (1 - f)◦(x*Wc)
c->assign(f * (*c0) + (1.f - f) * z({0, 0 ,0, inSize}) );
// *c = f*(*c0 - z({},{0, inSize})) + z({{},{0, inSize}});
// current cell output = r◦activation(c) + (1 - r)◦x
h->assign( r * activation(*c) + (1.f - r) * (*x) );
// *h = r * (activation<T>(c) - *x) + *x;
}
//////////////////////////////////////////////////////////////////////////
void sruTimeLoop(nd4j::LaunchContext * context, const NDArray* x, const NDArray* c0, const NDArray* w, const NDArray* b, NDArray* h, NDArray* c) {
// x input [bS x inSize x time]
// c0 initial cell state (at time step = 0) [bS x inSize],
// w weights, [3*inSize x inSize]
// b biases, [2*inSize]
// h cell outputs [bS x inSize x time]
// c cell states [bS x inSize x time]
auto wT = w->transpose(); // [3*inSize x inSize] -> [inSize x 3*inSize]
const int time = x->sizeAt(2);
NDArray ct_1(*c0);
// loop through time steps
for (int t = 0; t < time; ++t) {
auto xt = (*x)({0,0, 0,0, t,t+1});
auto ht = (*h)({0,0, 0,0, t,t+1});
auto ct = (*c)({0,0, 0,0, t,t+1});
helpers::sruCell(context, &xt, &ct_1, &wT, b, &ht, &ct);
ct_1.assign(ct);
}
}
//////////////////////////////////////////////////////////////////////////
template <typename T>
static void sruBI_(NDArray* x, const NDArray* w, const NDArray* b, const NDArray* c0, const NDArray* mask, NDArray* ht, NDArray* ct) {
}
//////////////////////////////////////////////////////////////////////////
template <typename T>
static void sruBIBP_(NDArray* x, const NDArray* w, const NDArray* b, const NDArray* c0, const NDArray* ct, const NDArray* inGradC0, const NDArray* inGradHt, const NDArray* mask,
NDArray* gradI, NDArray* gradW, NDArray* gradB, NDArray* gradC0) {
}
void sruBI(nd4j::LaunchContext * context, NDArray* x, const NDArray* w, const NDArray* b, const NDArray* c0, const NDArray* mask, NDArray* ht, NDArray* ct) {
BUILD_SINGLE_SELECTOR(x->dataType(), sruBI_, (x, w, b, c0, mask, ht, ct), FLOAT_TYPES);
}
void sruBIBP(nd4j::LaunchContext * context, NDArray* x, const NDArray* w, const NDArray* b, const NDArray* c0, const NDArray* ct, const NDArray* inGradC0, const NDArray* inGradH, const NDArray* mask, NDArray* gradI, NDArray* gradW, NDArray* gradB, NDArray* gradC0) {
BUILD_SINGLE_SELECTOR(x->dataType(), sruBIBP_, (x, w, b, c0, ct, inGradC0, inGradH, mask, gradI, gradW, gradB, gradC0), FLOAT_TYPES);
}
BUILD_SINGLE_TEMPLATE(template void sruBI_, (NDArray* x, const NDArray* w, const NDArray* b, const NDArray* c0, const NDArray* mask, NDArray* ht, NDArray* ct), FLOAT_TYPES);
BUILD_SINGLE_TEMPLATE(template void sruBIBP_, (NDArray* x, const NDArray* w, const NDArray* b, const NDArray* c0, const NDArray* ct, const NDArray* inGradC0, const NDArray* inGradH, const NDArray* mask, NDArray* gradI, NDArray* gradW, NDArray* gradB, NDArray* gradC0), FLOAT_TYPES);
}
}
}