ext/nmatrix/math/laswp.h
/////////////////////////////////////////////////////////////////////
// = NMatrix
//
// A linear algebra library for scientific computation in Ruby.
// NMatrix is part of SciRuby.
//
// NMatrix was originally inspired by and derived from NArray, by
// Masahiro Tanaka: http://narray.rubyforge.org
//
// == Copyright Information
//
// SciRuby is Copyright (c) 2010 - 2014, Ruby Science Foundation
// NMatrix is Copyright (c) 2012 - 2014, John Woods and the Ruby Science Foundation
//
// Please see LICENSE.txt for additional copyright notices.
//
// == Contributing
//
// By contributing source code to SciRuby, you agree to be bound by
// our Contributor Agreement:
//
// * https://github.com/SciRuby/sciruby/wiki/Contributor-Agreement
//
// == laswp.h
//
// laswp function in native C++.
//
/*
* Automatically Tuned Linear Algebra Software v3.8.4
* (C) Copyright 1999 R. Clint Whaley
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions, and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the ATLAS group or the names of its contributers may
* not be used to endorse or promote products derived from this
* software without specific written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ATLAS GROUP OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef LASWP_H
#define LASWP_H
namespace nm { namespace math {
/*
* ATLAS function which performs row interchanges on a general rectangular matrix. Modeled after the LAPACK LASWP function.
*
* This version is templated for use by template <> getrf().
*/
template <typename DType>
inline void laswp(const int N, DType* A, const int lda, const int K1, const int K2, const int *piv, const int inci) {
//const int n = K2 - K1; // not sure why this is declared. commented it out because it's unused.
int nb = N >> 5;
const int mr = N - (nb<<5);
const int incA = lda << 5;
if (K2 < K1) return;
int i1, i2;
if (inci < 0) {
piv -= (K2-1) * inci;
i1 = K2 - 1;
i2 = K1;
} else {
piv += K1 * inci;
i1 = K1;
i2 = K2-1;
}
if (nb) {
do {
const int* ipiv = piv;
int i = i1;
int KeepOn;
do {
int ip = *ipiv; ipiv += inci;
if (ip != i) {
DType *a0 = &(A[i]),
*a1 = &(A[ip]);
for (int h = 32; h; h--) {
DType r = *a0;
*a0 = *a1;
*a1 = r;
a0 += lda;
a1 += lda;
}
}
if (inci > 0) KeepOn = (++i <= i2);
else KeepOn = (--i >= i2);
} while (KeepOn);
A += incA;
} while (--nb);
}
if (mr) {
const int* ipiv = piv;
int i = i1;
int KeepOn;
do {
int ip = *ipiv; ipiv += inci;
if (ip != i) {
DType *a0 = &(A[i]),
*a1 = &(A[ip]);
for (int h = mr; h; h--) {
DType r = *a0;
*a0 = *a1;
*a1 = r;
a0 += lda;
a1 += lda;
}
}
if (inci > 0) KeepOn = (++i <= i2);
else KeepOn = (--i >= i2);
} while (KeepOn);
}
}
/*
* Function signature conversion for calling LAPACK's laswp functions as directly as possible.
*
* For documentation: http://www.netlib.org/lapack/double/dlaswp.f
*
* This function should normally go in math.cpp, but we need it to be available to nmatrix.cpp.
*/
template <typename DType>
inline void clapack_laswp(const int n, void* a, const int lda, const int k1, const int k2, const int* ipiv, const int incx) {
laswp<DType>(n, reinterpret_cast<DType*>(a), lda, k1, k2, ipiv, incx);
}
} } // namespace nm::math
#endif // LASWP_H