Annotation of rpl/lapack/lapack/dlaswp.f, revision 1.8
1.8 ! bertrand 1: *> \brief \b DLASWP
! 2: *
! 3: * =========== DOCUMENTATION ===========
! 4: *
! 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
! 7: *
! 8: *> \htmlonly
! 9: *> Download DLASWP + dependencies
! 10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaswp.f">
! 11: *> [TGZ]</a>
! 12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaswp.f">
! 13: *> [ZIP]</a>
! 14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaswp.f">
! 15: *> [TXT]</a>
! 16: *> \endhtmlonly
! 17: *
! 18: * Definition:
! 19: * ===========
! 20: *
! 21: * SUBROUTINE DLASWP( N, A, LDA, K1, K2, IPIV, INCX )
! 22: *
! 23: * .. Scalar Arguments ..
! 24: * INTEGER INCX, K1, K2, LDA, N
! 25: * ..
! 26: * .. Array Arguments ..
! 27: * INTEGER IPIV( * )
! 28: * DOUBLE PRECISION A( LDA, * )
! 29: * ..
! 30: *
! 31: *
! 32: *> \par Purpose:
! 33: * =============
! 34: *>
! 35: *> \verbatim
! 36: *>
! 37: *> DLASWP performs a series of row interchanges on the matrix A.
! 38: *> One row interchange is initiated for each of rows K1 through K2 of A.
! 39: *> \endverbatim
! 40: *
! 41: * Arguments:
! 42: * ==========
! 43: *
! 44: *> \param[in] N
! 45: *> \verbatim
! 46: *> N is INTEGER
! 47: *> The number of columns of the matrix A.
! 48: *> \endverbatim
! 49: *>
! 50: *> \param[in,out] A
! 51: *> \verbatim
! 52: *> A is DOUBLE PRECISION array, dimension (LDA,N)
! 53: *> On entry, the matrix of column dimension N to which the row
! 54: *> interchanges will be applied.
! 55: *> On exit, the permuted matrix.
! 56: *> \endverbatim
! 57: *>
! 58: *> \param[in] LDA
! 59: *> \verbatim
! 60: *> LDA is INTEGER
! 61: *> The leading dimension of the array A.
! 62: *> \endverbatim
! 63: *>
! 64: *> \param[in] K1
! 65: *> \verbatim
! 66: *> K1 is INTEGER
! 67: *> The first element of IPIV for which a row interchange will
! 68: *> be done.
! 69: *> \endverbatim
! 70: *>
! 71: *> \param[in] K2
! 72: *> \verbatim
! 73: *> K2 is INTEGER
! 74: *> The last element of IPIV for which a row interchange will
! 75: *> be done.
! 76: *> \endverbatim
! 77: *>
! 78: *> \param[in] IPIV
! 79: *> \verbatim
! 80: *> IPIV is INTEGER array, dimension (K2*abs(INCX))
! 81: *> The vector of pivot indices. Only the elements in positions
! 82: *> K1 through K2 of IPIV are accessed.
! 83: *> IPIV(K) = L implies rows K and L are to be interchanged.
! 84: *> \endverbatim
! 85: *>
! 86: *> \param[in] INCX
! 87: *> \verbatim
! 88: *> INCX is INTEGER
! 89: *> The increment between successive values of IPIV. If IPIV
! 90: *> is negative, the pivots are applied in reverse order.
! 91: *> \endverbatim
! 92: *
! 93: * Authors:
! 94: * ========
! 95: *
! 96: *> \author Univ. of Tennessee
! 97: *> \author Univ. of California Berkeley
! 98: *> \author Univ. of Colorado Denver
! 99: *> \author NAG Ltd.
! 100: *
! 101: *> \date November 2011
! 102: *
! 103: *> \ingroup doubleOTHERauxiliary
! 104: *
! 105: *> \par Further Details:
! 106: * =====================
! 107: *>
! 108: *> \verbatim
! 109: *>
! 110: *> Modified by
! 111: *> R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA
! 112: *> \endverbatim
! 113: *>
! 114: * =====================================================================
1.1 bertrand 115: SUBROUTINE DLASWP( N, A, LDA, K1, K2, IPIV, INCX )
116: *
1.8 ! bertrand 117: * -- LAPACK auxiliary routine (version 3.4.0) --
1.1 bertrand 118: * -- LAPACK is a software package provided by Univ. of Tennessee, --
119: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.8 ! bertrand 120: * November 2011
1.1 bertrand 121: *
122: * .. Scalar Arguments ..
123: INTEGER INCX, K1, K2, LDA, N
124: * ..
125: * .. Array Arguments ..
126: INTEGER IPIV( * )
127: DOUBLE PRECISION A( LDA, * )
128: * ..
129: *
130: * =====================================================================
131: *
132: * .. Local Scalars ..
133: INTEGER I, I1, I2, INC, IP, IX, IX0, J, K, N32
134: DOUBLE PRECISION TEMP
135: * ..
136: * .. Executable Statements ..
137: *
138: * Interchange row I with row IPIV(I) for each of rows K1 through K2.
139: *
140: IF( INCX.GT.0 ) THEN
141: IX0 = K1
142: I1 = K1
143: I2 = K2
144: INC = 1
145: ELSE IF( INCX.LT.0 ) THEN
146: IX0 = 1 + ( 1-K2 )*INCX
147: I1 = K2
148: I2 = K1
149: INC = -1
150: ELSE
151: RETURN
152: END IF
153: *
154: N32 = ( N / 32 )*32
155: IF( N32.NE.0 ) THEN
156: DO 30 J = 1, N32, 32
157: IX = IX0
158: DO 20 I = I1, I2, INC
159: IP = IPIV( IX )
160: IF( IP.NE.I ) THEN
161: DO 10 K = J, J + 31
162: TEMP = A( I, K )
163: A( I, K ) = A( IP, K )
164: A( IP, K ) = TEMP
165: 10 CONTINUE
166: END IF
167: IX = IX + INCX
168: 20 CONTINUE
169: 30 CONTINUE
170: END IF
171: IF( N32.NE.N ) THEN
172: N32 = N32 + 1
173: IX = IX0
174: DO 50 I = I1, I2, INC
175: IP = IPIV( IX )
176: IF( IP.NE.I ) THEN
177: DO 40 K = N32, N
178: TEMP = A( I, K )
179: A( I, K ) = A( IP, K )
180: A( IP, K ) = TEMP
181: 40 CONTINUE
182: END IF
183: IX = IX + INCX
184: 50 CONTINUE
185: END IF
186: *
187: RETURN
188: *
189: * End of DLASWP
190: *
191: END
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