cavis/libnd4j/include/helpers/impl/householder.cpp

221 lines
6.1 KiB
C++

/* ******************************************************************************
*
*
* 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.
*
* See the NOTICE file distributed with this work for additional
* information regarding copyright ownership.
* 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
******************************************************************************/
//
// Created by Yurii Shyrma on 18.12.2017
//
#include <helpers/householder.h>
namespace sd {
namespace ops {
namespace helpers {
//////////////////////////////////////////////////////////////////////////
// template <typename T>
// NDArray Householder<T>::evalHHmatrix(const NDArray& x) {
// // input validation
// if(x.rankOf() != 1 && !x.isScalar())
// throw std::runtime_error("ops::helpers::Householder::evalHHmatrix method: iinput array must have rank = 1 or to be scalar!");
// const auto xLen = x.lengthOf();
// NDArray w(x.ordering(), {xLen, 1}, x.dataType(), x.getContext()); // column-vector
// NDArray xTail = xLen > 1 ? x({1,-1}) : NDArray();
// T tailXnorm = xLen > 1 ? xTail.reduceNumber(reduce::SquaredNorm).t<T>(0) : (T)0;
// const auto xFirstElem = x.t<T>(0);
// T coeff, normX;
// if(tailXnorm <= DataTypeUtils::min<T>()) {
// normX = xFirstElem;
// coeff = 0.f;
// if(xLen > 1)
// w({1,-1, 0,0}) = 0.f;
// }
// else {
// normX = math::nd4j_sqrt<T,T>(xFirstElem*xFirstElem + tailXnorm);
// if(xFirstElem >= (T)0.f)
// normX = -normX; // choose opposite sign to lessen roundoff error
// coeff = (normX - xFirstElem) / normX;
// if(xLen > 1)
// w({1,-1, 0,0}).assign(xTail / (xFirstElem - normX));
// }
// w.t<T>(0) = (T)1;
// NDArray identity(x.ordering(), {xLen, xLen}, x.dataType(), x.getContext());
// identity.setIdentity(); // identity matrix
// return identity - mmul(w, w.transpose()) * coeff;
// }
//////////////////////////////////////////////////////////////////////////
template <typename T>
void Householder<T>::evalHHmatrixData(const NDArray& x, NDArray& tail, T& coeff, T& normX) {
// input validation
if(x.rankOf() != 1 && !x.isScalar())
throw std::runtime_error("ops::helpers::Householder::evalHHmatrixData method: input array must have rank = 1 or to be scalar!");
if(!x.isScalar() && x.lengthOf() != tail.lengthOf() + 1)
throw std::runtime_error("ops::helpers::Householder::evalHHmatrixData method: input tail vector must have length less than unity compared to input x vector!");
const auto xLen = x.lengthOf();
const NDArray xTail = xLen > 1 ? x({1,-1}) : NDArray();
T tailXnorm = xLen > 1 ? xTail.reduceNumber(reduce::SquaredNorm).t<T>(0) : (T)0;
const auto xFirstElem = x.t<T>(0);
if(tailXnorm <= DataTypeUtils::min<T>()) {
normX = xFirstElem;
coeff = (T)0.f;
tail = (T)0.f;
}
else {
normX = math::nd4j_sqrt<T,T>(xFirstElem*xFirstElem + tailXnorm);
if(xFirstElem >= (T)0.f)
normX = -normX; // choose opposite sign to lessen roundoff error
coeff = (normX - xFirstElem) / normX;
tail.assign(xTail / (xFirstElem - normX));
}
}
//////////////////////////////////////////////////////////////////////////
template <typename T>
void Householder<T>::evalHHmatrixDataI(NDArray& x, T& coeff, T& normX) {
// input validation
if(x.rankOf() != 1 && !x.isScalar())
throw std::runtime_error("ops::helpers::Householder::evalHHmatrixDataI method: input array must have rank = 1 or to be scalar!");
int rows = (int)x.lengthOf()-1;
int num = 1;
if(rows == 0) {
rows = 1;
num = 0;
}
NDArray tail = x({num, -1});
evalHHmatrixData(x, tail, coeff, normX);
}
//////////////////////////////////////////////////////////////////////////
template <typename T>
void Householder<T>::mulLeft(NDArray& matrix, const NDArray& tail, const T coeff) {
// if(matrix.rankOf() != 2)
// throw "ops::helpers::Householder::mulLeft method: input array must be 2D matrix !";
if(matrix.sizeAt(0) == 1 && coeff != (T)0) {
matrix *= (T) 1.f - coeff;
}
else if(coeff != (T)0.f) {
NDArray bottomPart = matrix({1,matrix.sizeAt(0), 0,0}, true);
NDArray fistRow = matrix({0,1, 0,0}, true);
if(tail.isColumnVector()) {
auto resultingRow = mmul(tail.transpose(), bottomPart);
resultingRow += fistRow;
resultingRow *= coeff;
fistRow -= resultingRow;
bottomPart -= mmul(tail, resultingRow);
}
else {
auto resultingRow = mmul(tail, bottomPart);
resultingRow += fistRow;
resultingRow *= coeff;
fistRow -= resultingRow;
bottomPart -= mmul(tail.transpose(), resultingRow);
}
}
}
//////////////////////////////////////////////////////////////////////////
template <typename T>
void Householder<T>::mulRight(NDArray& matrix, const NDArray& tail, const T coeff) {
// if(matrix.rankOf() != 2)
// throw "ops::helpers::Householder::mulRight method: input array must be 2D matrix !";
if(matrix.sizeAt(1) == 1 && coeff != (T)0) {
matrix *= (T)1.f - coeff;
}
else if(coeff != (T)0.f) {
NDArray rightPart = matrix({0,0, 1,matrix.sizeAt(1)}, true);
NDArray fistCol = matrix({0,0, 0,1}, true);
if(tail.isColumnVector()) {
auto resultingCol = mmul(rightPart, tail);
resultingCol += fistCol;
resultingCol *= coeff;
fistCol -= resultingCol;
rightPart -= mmul(resultingCol, tail.transpose());
}
else {
auto resultingCol = mmul(rightPart, tail.transpose());
resultingCol += fistCol;
resultingCol *= coeff;
fistCol -= resultingCol;
rightPart -= mmul(resultingCol, tail);
}
}
}
template class ND4J_EXPORT Householder<float>;
template class ND4J_EXPORT Householder<float16>;
template class ND4J_EXPORT Householder<bfloat16>;
template class ND4J_EXPORT Householder<double>;
}
}
}