/* sla_rpvgrw.f -- translated by f2c (version 20061008). 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" #include "blaswrap.h" doublereal sla_rpvgrw__(integer *n, integer *ncols, real *a, integer *lda, real *af, integer *ldaf) { /* System generated locals */ integer a_dim1, a_offset, af_dim1, af_offset, i__1, i__2; real ret_val, r__1, r__2; /* Local variables */ integer i__, j; real amax, umax, rpvgrw; /* -- LAPACK routine (version 3.2.1) -- */ /* -- Contributed by James Demmel, Deaglan Halligan, Yozo Hida and -- */ /* -- Jason Riedy of Univ. of California Berkeley. -- */ /* -- April 2009 -- */ /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */ /* -- Univ. of California Berkeley and NAG Ltd. -- */ /* .. */ /* .. Scalar Arguments .. */ /* .. */ /* .. Array Arguments .. */ /* .. */ /* Purpose */ /* ======= */ /* SLA_RPVGRW computes the reciprocal pivot growth factor */ /* norm(A)/norm(U). The "max absolute element" norm is used. If this is */ /* much less than 1, the stability of the LU factorization of the */ /* (equilibrated) matrix A could be poor. This also means that the */ /* solution X, estimated condition numbers, and error bounds could be */ /* unreliable. */ /* Arguments */ /* ========= */ /* N (input) INTEGER */ /* The number of linear equations, i.e., the order of the */ /* matrix A. N >= 0. */ /* NCOLS (input) INTEGER */ /* The number of columns of the matrix A. NCOLS >= 0. */ /* A (input) REAL array, dimension (LDA,N) */ /* On entry, the N-by-N matrix A. */ /* LDA (input) INTEGER */ /* The leading dimension of the array A. LDA >= max(1,N). */ /* AF (input) REAL array, dimension (LDAF,N) */ /* The factors L and U from the factorization */ /* A = P*L*U as computed by SGETRF. */ /* LDAF (input) INTEGER */ /* The leading dimension of the array AF. LDAF >= max(1,N). */ /* ===================================================================== */ /* .. Local Scalars .. */ /* .. */ /* .. Intrinsic Functions .. */ /* .. */ /* .. Executable Statements .. */ /* Parameter adjustments */ a_dim1 = *lda; a_offset = 1 + a_dim1; a -= a_offset; af_dim1 = *ldaf; af_offset = 1 + af_dim1; af -= af_offset; /* Function Body */ rpvgrw = 1.f; i__1 = *ncols; for (j = 1; j <= i__1; ++j) { amax = 0.f; umax = 0.f; i__2 = *n; for (i__ = 1; i__ <= i__2; ++i__) { /* Computing MAX */ r__2 = (r__1 = a[i__ + j * a_dim1], dabs(r__1)); amax = dmax(r__2,amax); } i__2 = j; for (i__ = 1; i__ <= i__2; ++i__) { /* Computing MAX */ r__2 = (r__1 = af[i__ + j * af_dim1], dabs(r__1)); umax = dmax(r__2,umax); } if (umax != 0.f) { /* Computing MIN */ r__1 = amax / umax; rpvgrw = dmin(r__1,rpvgrw); } } ret_val = rpvgrw; return ret_val; } /* sla_rpvgrw__ */