File size: 11,906 Bytes
b1b3bae | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 | #region Translated by Jose Antonio De Santiago-Castillo.
//Translated by Jose Antonio De Santiago-Castillo.
//E-mail:JAntonioDeSantiago@gmail.com
//Website: www.DotNumerics.com
//
//Fortran to C# Translation.
//Translated by:
//F2CSharp Version 0.72 (Dicember 7, 2009)
//Code Optimizations: , assignment operator, for-loop: array indexes
//
#endregion
using System;
using DotNumerics.FortranLibrary;
namespace DotNumerics.LinearAlgebra.CSLapack
{
/// <summary>
/// -- LAPACK routine (version 3.1) --
/// Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
/// November 2006
/// Purpose
/// =======
///
/// DGETF2 computes an LU factorization of a general m-by-n matrix A
/// using partial pivoting with row interchanges.
///
/// The factorization has the form
/// A = P * L * U
/// where P is a permutation matrix, L is lower triangular with unit
/// diagonal elements (lower trapezoidal if m .GT. n), and U is upper
/// triangular (upper trapezoidal if m .LT. n).
///
/// This is the right-looking Level 2 BLAS version of the algorithm.
///
///</summary>
public class DGETF2
{
#region Dependencies
DLAMCH _dlamch; IDAMAX _idamax; DGER _dger; DSCAL _dscal; DSWAP _dswap; XERBLA _xerbla;
#endregion
#region Variables
const double ONE = 1.0E+0; const double ZERO = 0.0E+0;
#endregion
public DGETF2(DLAMCH dlamch, IDAMAX idamax, DGER dger, DSCAL dscal, DSWAP dswap, XERBLA xerbla)
{
#region Set Dependencies
this._dlamch = dlamch; this._idamax = idamax; this._dger = dger; this._dscal = dscal; this._dswap = dswap;
this._xerbla = xerbla;
#endregion
}
public DGETF2()
{
#region Dependencies (Initialization)
LSAME lsame = new LSAME();
DLAMC3 dlamc3 = new DLAMC3();
IDAMAX idamax = new IDAMAX();
XERBLA xerbla = new XERBLA();
DSCAL dscal = new DSCAL();
DSWAP dswap = new DSWAP();
DLAMC1 dlamc1 = new DLAMC1(dlamc3);
DLAMC4 dlamc4 = new DLAMC4(dlamc3);
DLAMC5 dlamc5 = new DLAMC5(dlamc3);
DLAMC2 dlamc2 = new DLAMC2(dlamc3, dlamc1, dlamc4, dlamc5);
DLAMCH dlamch = new DLAMCH(lsame, dlamc2);
DGER dger = new DGER(xerbla);
#endregion
#region Set Dependencies
this._dlamch = dlamch; this._idamax = idamax; this._dger = dger; this._dscal = dscal; this._dswap = dswap;
this._xerbla = xerbla;
#endregion
}
/// <summary>
/// Purpose
/// =======
///
/// DGETF2 computes an LU factorization of a general m-by-n matrix A
/// using partial pivoting with row interchanges.
///
/// The factorization has the form
/// A = P * L * U
/// where P is a permutation matrix, L is lower triangular with unit
/// diagonal elements (lower trapezoidal if m .GT. n), and U is upper
/// triangular (upper trapezoidal if m .LT. n).
///
/// This is the right-looking Level 2 BLAS version of the algorithm.
///
///</summary>
/// <param name="M">
/// (input) INTEGER
/// The number of rows of the matrix A. M .GE. 0.
///</param>
/// <param name="N">
/// (input) INTEGER
/// The number of columns of the matrix A. N .GE. 0.
///</param>
/// <param name="A">
/// (input/output) DOUBLE PRECISION array, dimension (LDA,N)
/// On entry, the m by n matrix to be factored.
/// On exit, the factors L and U from the factorization
/// A = P*L*U; the unit diagonal elements of L are not stored.
///</param>
/// <param name="LDA">
/// (input) INTEGER
/// The leading dimension of the array A. LDA .GE. max(1,M).
///</param>
/// <param name="IPIV">
/// (output) INTEGER array, dimension (min(M,N))
/// The pivot indices; for 1 .LE. i .LE. min(M,N), row i of the
/// matrix was interchanged with row IPIV(i).
///</param>
/// <param name="INFO">
/// (output) INTEGER
/// = 0: successful exit
/// .LT. 0: if INFO = -k, the k-th argument had an illegal value
/// .GT. 0: if INFO = k, U(k,k) is exactly zero. The factorization
/// has been completed, but the factor U is exactly
/// singular, and division by zero will occur if it is used
/// to solve a system of equations.
///</param>
public void Run(int M, int N, ref double[] A, int offset_a, int LDA, ref int[] IPIV, int offset_ipiv, ref int INFO)
{
#region Variables
double SFMIN = 0; int I = 0; int J = 0; int JP = 0;
#endregion
#region Implicit Variables
int A_J = 0;
#endregion
#region Array Index Correction
int o_a = -1 - LDA + offset_a; int o_ipiv = -1 + offset_ipiv;
#endregion
#region Prolog
// *
// * -- LAPACK routine (version 3.1) --
// * Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
// * November 2006
// *
// * .. Scalar Arguments ..
// * ..
// * .. Array Arguments ..
// * ..
// *
// * Purpose
// * =======
// *
// * DGETF2 computes an LU factorization of a general m-by-n matrix A
// * using partial pivoting with row interchanges.
// *
// * The factorization has the form
// * A = P * L * U
// * where P is a permutation matrix, L is lower triangular with unit
// * diagonal elements (lower trapezoidal if m > n), and U is upper
// * triangular (upper trapezoidal if m < n).
// *
// * This is the right-looking Level 2 BLAS version of the algorithm.
// *
// * Arguments
// * =========
// *
// * M (input) INTEGER
// * The number of rows of the matrix A. M >= 0.
// *
// * N (input) INTEGER
// * The number of columns of the matrix A. N >= 0.
// *
// * A (input/output) DOUBLE PRECISION array, dimension (LDA,N)
// * On entry, the m by n matrix to be factored.
// * On exit, the factors L and U from the factorization
// * A = P*L*U; the unit diagonal elements of L are not stored.
// *
// * LDA (input) INTEGER
// * The leading dimension of the array A. LDA >= max(1,M).
// *
// * IPIV (output) INTEGER array, dimension (min(M,N))
// * The pivot indices; for 1 <= i <= min(M,N), row i of the
// * matrix was interchanged with row IPIV(i).
// *
// * INFO (output) INTEGER
// * = 0: successful exit
// * < 0: if INFO = -k, the k-th argument had an illegal value
// * > 0: if INFO = k, U(k,k) is exactly zero. The factorization
// * has been completed, but the factor U is exactly
// * singular, and division by zero will occur if it is used
// * to solve a system of equations.
// *
// * =====================================================================
// *
// * .. Parameters ..
// * ..
// * .. Local Scalars ..
// * ..
// * .. External Functions ..
// * ..
// * .. External Subroutines ..
// * ..
// * .. Intrinsic Functions ..
// INTRINSIC MAX, MIN;
// * ..
// * .. Executable Statements ..
// *
// * Test the input parameters.
// *
#endregion
#region Body
INFO = 0;
if (M < 0)
{
INFO = - 1;
}
else
{
if (N < 0)
{
INFO = - 2;
}
else
{
if (LDA < Math.Max(1, M))
{
INFO = - 4;
}
}
}
if (INFO != 0)
{
this._xerbla.Run("DGETF2", - INFO);
return;
}
// *
// * Quick return if possible
// *
if (M == 0 || N == 0) return;
// *
// * Compute machine safe minimum
// *
SFMIN = this._dlamch.Run("S");
// *
for (J = 1; J <= Math.Min(M, N); J++)
{
// *
// * Find pivot and test for singularity.
// *
JP = J - 1 + this._idamax.Run(M - J + 1, A, J+J * LDA + o_a, 1);
IPIV[J + o_ipiv] = JP;
if (A[JP+J * LDA + o_a] != ZERO)
{
// *
// * Apply the interchange to columns 1:N.
// *
if (JP != J) this._dswap.Run(N, ref A, J+1 * LDA + o_a, LDA, ref A, JP+1 * LDA + o_a, LDA);
// *
// * Compute elements J+1:M of J-th column.
// *
if (J < M)
{
if (Math.Abs(A[J+J * LDA + o_a]) >= SFMIN)
{
this._dscal.Run(M - J, ONE / A[J+J * LDA + o_a], ref A, J + 1+J * LDA + o_a, 1);
}
else
{
A_J = J * LDA + o_a;
for (I = 1; I <= M - J; I++)
{
A[J + I + A_J] /= A[J+J * LDA + o_a];
}
}
}
// *
}
else
{
if (INFO == 0)
{
// *
INFO = J;
}
}
// *
if (J < Math.Min(M, N))
{
// *
// * Update trailing submatrix.
// *
this._dger.Run(M - J, N - J, - ONE, A, J + 1+J * LDA + o_a, 1, A, J+(J + 1) * LDA + o_a
, LDA, ref A, J + 1+(J + 1) * LDA + o_a, LDA);
}
}
return;
// *
// * End of DGETF2
// *
#endregion
}
}
}
|