/* -- translated by f2c (version 20100827). You must link the resulting object file with libf2c: on Microsoft Windows system, link with libf2c.lib; on Linux or Unix systems, link with .../path/to/libf2c.a -lm or, if you install libf2c.a in a standard place, with -lf2c -lm -- in that order, at the end of the command line, as in cc *.o -lf2c -lm Source for libf2c is in /netlib/f2c/libf2c.zip, e.g., http://www.netlib.org/f2c/libf2c.zip */ #include "f2c.h" /* > \brief \b DLASR applies a sequence of plane rotations to a general rectangular matrix. =========== DOCUMENTATION =========== Online html documentation available at http://www.netlib.org/lapack/explore-html/ > \htmlonly > Download DLASR + dependencies > > [TGZ] > > [ZIP] > > [TXT] > \endhtmlonly Definition: =========== SUBROUTINE DLASR( SIDE, PIVOT, DIRECT, M, N, C, S, A, LDA ) CHARACTER DIRECT, PIVOT, SIDE INTEGER LDA, M, N DOUBLE PRECISION A( LDA, * ), C( * ), S( * ) > \par Purpose: ============= > > \verbatim > > DLASR applies a sequence of plane rotations to a real matrix A, > from either the left or the right. > > When SIDE = 'L', the transformation takes the form > > A := P*A > > and when SIDE = 'R', the transformation takes the form > > A := A*P**T > > where P is an orthogonal matrix consisting of a sequence of z plane > rotations, with z = M when SIDE = 'L' and z = N when SIDE = 'R', > and P**T is the transpose of P. > > When DIRECT = 'F' (Forward sequence), then > > P = P(z-1) * ... * P(2) * P(1) > > and when DIRECT = 'B' (Backward sequence), then > > P = P(1) * P(2) * ... * P(z-1) > > where P(k) is a plane rotation matrix defined by the 2-by-2 rotation > > R(k) = ( c(k) s(k) ) > = ( -s(k) c(k) ). > > When PIVOT = 'V' (Variable pivot), the rotation is performed > for the plane (k,k+1), i.e., P(k) has the form > > P(k) = ( 1 ) > ( ... ) > ( 1 ) > ( c(k) s(k) ) > ( -s(k) c(k) ) > ( 1 ) > ( ... ) > ( 1 ) > > where R(k) appears as a rank-2 modification to the identity matrix in > rows and columns k and k+1. > > When PIVOT = 'T' (Top pivot), the rotation is performed for the > plane (1,k+1), so P(k) has the form > > P(k) = ( c(k) s(k) ) > ( 1 ) > ( ... ) > ( 1 ) > ( -s(k) c(k) ) > ( 1 ) > ( ... ) > ( 1 ) > > where R(k) appears in rows and columns 1 and k+1. > > Similarly, when PIVOT = 'B' (Bottom pivot), the rotation is > performed for the plane (k,z), giving P(k) the form > > P(k) = ( 1 ) > ( ... ) > ( 1 ) > ( c(k) s(k) ) > ( 1 ) > ( ... ) > ( 1 ) > ( -s(k) c(k) ) > > where R(k) appears in rows and columns k and z. The rotations are > performed without ever forming P(k) explicitly. > \endverbatim Arguments: ========== > \param[in] SIDE > \verbatim > SIDE is CHARACTER*1 > Specifies whether the plane rotation matrix P is applied to > A on the left or the right. > = 'L': Left, compute A := P*A > = 'R': Right, compute A:= A*P**T > \endverbatim > > \param[in] PIVOT > \verbatim > PIVOT is CHARACTER*1 > Specifies the plane for which P(k) is a plane rotation > matrix. > = 'V': Variable pivot, the plane (k,k+1) > = 'T': Top pivot, the plane (1,k+1) > = 'B': Bottom pivot, the plane (k,z) > \endverbatim > > \param[in] DIRECT > \verbatim > DIRECT is CHARACTER*1 > Specifies whether P is a forward or backward sequence of > plane rotations. > = 'F': Forward, P = P(z-1)*...*P(2)*P(1) > = 'B': Backward, P = P(1)*P(2)*...*P(z-1) > \endverbatim > > \param[in] M > \verbatim > M is INTEGER > The number of rows of the matrix A. If m <= 1, an immediate > return is effected. > \endverbatim > > \param[in] N > \verbatim > N is INTEGER > The number of columns of the matrix A. If n <= 1, an > immediate return is effected. > \endverbatim > > \param[in] C > \verbatim > C is DOUBLE PRECISION array, dimension > (M-1) if SIDE = 'L' > (N-1) if SIDE = 'R' > The cosines c(k) of the plane rotations. > \endverbatim > > \param[in] S > \verbatim > S is DOUBLE PRECISION array, dimension > (M-1) if SIDE = 'L' > (N-1) if SIDE = 'R' > The sines s(k) of the plane rotations. The 2-by-2 plane > rotation part of the matrix P(k), R(k), has the form > R(k) = ( c(k) s(k) ) > ( -s(k) c(k) ). > \endverbatim > > \param[in,out] A > \verbatim > A is DOUBLE PRECISION array, dimension (LDA,N) > The M-by-N matrix A. On exit, A is overwritten by P*A if > SIDE = 'R' or by A*P**T if SIDE = 'L'. > \endverbatim > > \param[in] LDA > \verbatim > LDA is INTEGER > The leading dimension of the array A. LDA >= max(1,M). > \endverbatim Authors: ======== > \author Univ. of Tennessee > \author Univ. of California Berkeley > \author Univ. of Colorado Denver > \author NAG Ltd. > \date September 2012 > \ingroup auxOTHERauxiliary ===================================================================== Subroutine */ int igraphdlasr_(char *side, char *pivot, char *direct, integer *m, integer *n, doublereal *c__, doublereal *s, doublereal *a, integer * lda) { /* System generated locals */ integer a_dim1, a_offset, i__1, i__2; /* Local variables */ integer i__, j, info; doublereal temp; extern logical igraphlsame_(char *, char *); doublereal ctemp, stemp; extern /* Subroutine */ int igraphxerbla_(char *, integer *, ftnlen); /* -- LAPACK auxiliary routine (version 3.4.2) -- -- LAPACK is a software package provided by Univ. of Tennessee, -- -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- September 2012 ===================================================================== Test the input parameters Parameter adjustments */ --c__; --s; a_dim1 = *lda; a_offset = 1 + a_dim1; a -= a_offset; /* Function Body */ info = 0; if (! (igraphlsame_(side, "L") || igraphlsame_(side, "R"))) { info = 1; } else if (! (igraphlsame_(pivot, "V") || igraphlsame_(pivot, "T") || igraphlsame_(pivot, "B"))) { info = 2; } else if (! (igraphlsame_(direct, "F") || igraphlsame_(direct, "B"))) { info = 3; } else if (*m < 0) { info = 4; } else if (*n < 0) { info = 5; } else if (*lda < max(1,*m)) { info = 9; } if (info != 0) { igraphxerbla_("DLASR ", &info, (ftnlen)6); return 0; } /* Quick return if possible */ if (*m == 0 || *n == 0) { return 0; } if (igraphlsame_(side, "L")) { /* Form P * A */ if (igraphlsame_(pivot, "V")) { if (igraphlsame_(direct, "F")) { i__1 = *m - 1; for (j = 1; j <= i__1; ++j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__2 = *n; for (i__ = 1; i__ <= i__2; ++i__) { temp = a[j + 1 + i__ * a_dim1]; a[j + 1 + i__ * a_dim1] = ctemp * temp - stemp * a[j + i__ * a_dim1]; a[j + i__ * a_dim1] = stemp * temp + ctemp * a[j + i__ * a_dim1]; /* L10: */ } } /* L20: */ } } else if (igraphlsame_(direct, "B")) { for (j = *m - 1; j >= 1; --j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { temp = a[j + 1 + i__ * a_dim1]; a[j + 1 + i__ * a_dim1] = ctemp * temp - stemp * a[j + i__ * a_dim1]; a[j + i__ * a_dim1] = stemp * temp + ctemp * a[j + i__ * a_dim1]; /* L30: */ } } /* L40: */ } } } else if (igraphlsame_(pivot, "T")) { if (igraphlsame_(direct, "F")) { i__1 = *m; for (j = 2; j <= i__1; ++j) { ctemp = c__[j - 1]; stemp = s[j - 1]; if (ctemp != 1. || stemp != 0.) { i__2 = *n; for (i__ = 1; i__ <= i__2; ++i__) { temp = a[j + i__ * a_dim1]; a[j + i__ * a_dim1] = ctemp * temp - stemp * a[ i__ * a_dim1 + 1]; a[i__ * a_dim1 + 1] = stemp * temp + ctemp * a[ i__ * a_dim1 + 1]; /* L50: */ } } /* L60: */ } } else if (igraphlsame_(direct, "B")) { for (j = *m; j >= 2; --j) { ctemp = c__[j - 1]; stemp = s[j - 1]; if (ctemp != 1. || stemp != 0.) { i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { temp = a[j + i__ * a_dim1]; a[j + i__ * a_dim1] = ctemp * temp - stemp * a[ i__ * a_dim1 + 1]; a[i__ * a_dim1 + 1] = stemp * temp + ctemp * a[ i__ * a_dim1 + 1]; /* L70: */ } } /* L80: */ } } } else if (igraphlsame_(pivot, "B")) { if (igraphlsame_(direct, "F")) { i__1 = *m - 1; for (j = 1; j <= i__1; ++j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__2 = *n; for (i__ = 1; i__ <= i__2; ++i__) { temp = a[j + i__ * a_dim1]; a[j + i__ * a_dim1] = stemp * a[*m + i__ * a_dim1] + ctemp * temp; a[*m + i__ * a_dim1] = ctemp * a[*m + i__ * a_dim1] - stemp * temp; /* L90: */ } } /* L100: */ } } else if (igraphlsame_(direct, "B")) { for (j = *m - 1; j >= 1; --j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { temp = a[j + i__ * a_dim1]; a[j + i__ * a_dim1] = stemp * a[*m + i__ * a_dim1] + ctemp * temp; a[*m + i__ * a_dim1] = ctemp * a[*m + i__ * a_dim1] - stemp * temp; /* L110: */ } } /* L120: */ } } } } else if (igraphlsame_(side, "R")) { /* Form A * P**T */ if (igraphlsame_(pivot, "V")) { if (igraphlsame_(direct, "F")) { i__1 = *n - 1; for (j = 1; j <= i__1; ++j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__2 = *m; for (i__ = 1; i__ <= i__2; ++i__) { temp = a[i__ + (j + 1) * a_dim1]; a[i__ + (j + 1) * a_dim1] = ctemp * temp - stemp * a[i__ + j * a_dim1]; a[i__ + j * a_dim1] = stemp * temp + ctemp * a[ i__ + j * a_dim1]; /* L130: */ } } /* L140: */ } } else if (igraphlsame_(direct, "B")) { for (j = *n - 1; j >= 1; --j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__1 = *m; for (i__ = 1; i__ <= i__1; ++i__) { temp = a[i__ + (j + 1) * a_dim1]; a[i__ + (j + 1) * a_dim1] = ctemp * temp - stemp * a[i__ + j * a_dim1]; a[i__ + j * a_dim1] = stemp * temp + ctemp * a[ i__ + j * a_dim1]; /* L150: */ } } /* L160: */ } } } else if (igraphlsame_(pivot, "T")) { if (igraphlsame_(direct, "F")) { i__1 = *n; for (j = 2; j <= i__1; ++j) { ctemp = c__[j - 1]; stemp = s[j - 1]; if (ctemp != 1. || stemp != 0.) { i__2 = *m; for (i__ = 1; i__ <= i__2; ++i__) { temp = a[i__ + j * a_dim1]; a[i__ + j * a_dim1] = ctemp * temp - stemp * a[ i__ + a_dim1]; a[i__ + a_dim1] = stemp * temp + ctemp * a[i__ + a_dim1]; /* L170: */ } } /* L180: */ } } else if (igraphlsame_(direct, "B")) { for (j = *n; j >= 2; --j) { ctemp = c__[j - 1]; stemp = s[j - 1]; if (ctemp != 1. || stemp != 0.) { i__1 = *m; for (i__ = 1; i__ <= i__1; ++i__) { temp = a[i__ + j * a_dim1]; a[i__ + j * a_dim1] = ctemp * temp - stemp * a[ i__ + a_dim1]; a[i__ + a_dim1] = stemp * temp + ctemp * a[i__ + a_dim1]; /* L190: */ } } /* L200: */ } } } else if (igraphlsame_(pivot, "B")) { if (igraphlsame_(direct, "F")) { i__1 = *n - 1; for (j = 1; j <= i__1; ++j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__2 = *m; for (i__ = 1; i__ <= i__2; ++i__) { temp = a[i__ + j * a_dim1]; a[i__ + j * a_dim1] = stemp * a[i__ + *n * a_dim1] + ctemp * temp; a[i__ + *n * a_dim1] = ctemp * a[i__ + *n * a_dim1] - stemp * temp; /* L210: */ } } /* L220: */ } } else if (igraphlsame_(direct, "B")) { for (j = *n - 1; j >= 1; --j) { ctemp = c__[j]; stemp = s[j]; if (ctemp != 1. || stemp != 0.) { i__1 = *m; for (i__ = 1; i__ <= i__1; ++i__) { temp = a[i__ + j * a_dim1]; a[i__ + j * a_dim1] = stemp * a[i__ + *n * a_dim1] + ctemp * temp; a[i__ + *n * a_dim1] = ctemp * a[i__ + *n * a_dim1] - stemp * temp; /* L230: */ } } /* L240: */ } } } } return 0; /* End of DLASR */ } /* igraphdlasr_ */