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author | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
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committer | shmel1k <shmel1k@ydb.tech> | 2022-09-02 12:44:59 +0300 |
commit | 90d450f74722da7859d6f510a869f6c6908fd12f (patch) | |
tree | 538c718dedc76cdfe37ad6d01ff250dd930d9278 /contrib/libs/clapack/dpttrf.c | |
parent | 01f64c1ecd0d4ffa9e3a74478335f1745f26cc75 (diff) | |
download | ydb-90d450f74722da7859d6f510a869f6c6908fd12f.tar.gz |
[] add metering mode to CLI
Diffstat (limited to 'contrib/libs/clapack/dpttrf.c')
-rw-r--r-- | contrib/libs/clapack/dpttrf.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/contrib/libs/clapack/dpttrf.c b/contrib/libs/clapack/dpttrf.c new file mode 100644 index 0000000000..070ef3436e --- /dev/null +++ b/contrib/libs/clapack/dpttrf.c @@ -0,0 +1,181 @@ +/* dpttrf.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" + +/* Subroutine */ int dpttrf_(integer *n, doublereal *d__, doublereal *e, + integer *info) +{ + /* System generated locals */ + integer i__1; + + /* Local variables */ + integer i__, i4; + doublereal ei; + extern /* Subroutine */ int xerbla_(char *, integer *); + + +/* -- LAPACK routine (version 3.2) -- */ +/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */ +/* November 2006 */ + +/* .. Scalar Arguments .. */ +/* .. */ +/* .. Array Arguments .. */ +/* .. */ + +/* Purpose */ +/* ======= */ + +/* DPTTRF computes the L*D*L' factorization of a real symmetric */ +/* positive definite tridiagonal matrix A. The factorization may also */ +/* be regarded as having the form A = U'*D*U. */ + +/* Arguments */ +/* ========= */ + +/* N (input) INTEGER */ +/* The order of the matrix A. N >= 0. */ + +/* D (input/output) DOUBLE PRECISION array, dimension (N) */ +/* On entry, the n diagonal elements of the tridiagonal matrix */ +/* A. On exit, the n diagonal elements of the diagonal matrix */ +/* D from the L*D*L' factorization of A. */ + +/* E (input/output) DOUBLE PRECISION array, dimension (N-1) */ +/* On entry, the (n-1) subdiagonal elements of the tridiagonal */ +/* matrix A. On exit, the (n-1) subdiagonal elements of the */ +/* unit bidiagonal factor L from the L*D*L' factorization of A. */ +/* E can also be regarded as the superdiagonal of the unit */ +/* bidiagonal factor U from the U'*D*U factorization of A. */ + +/* INFO (output) INTEGER */ +/* = 0: successful exit */ +/* < 0: if INFO = -k, the k-th argument had an illegal value */ +/* > 0: if INFO = k, the leading minor of order k is not */ +/* positive definite; if k < N, the factorization could not */ +/* be completed, while if k = N, the factorization was */ +/* completed, but D(N) <= 0. */ + +/* ===================================================================== */ + +/* .. Parameters .. */ +/* .. */ +/* .. Local Scalars .. */ +/* .. */ +/* .. External Subroutines .. */ +/* .. */ +/* .. Intrinsic Functions .. */ +/* .. */ +/* .. Executable Statements .. */ + +/* Test the input parameters. */ + + /* Parameter adjustments */ + --e; + --d__; + + /* Function Body */ + *info = 0; + if (*n < 0) { + *info = -1; + i__1 = -(*info); + xerbla_("DPTTRF", &i__1); + return 0; + } + +/* Quick return if possible */ + + if (*n == 0) { + return 0; + } + +/* Compute the L*D*L' (or U'*D*U) factorization of A. */ + + i4 = (*n - 1) % 4; + i__1 = i4; + for (i__ = 1; i__ <= i__1; ++i__) { + if (d__[i__] <= 0.) { + *info = i__; + goto L30; + } + ei = e[i__]; + e[i__] = ei / d__[i__]; + d__[i__ + 1] -= e[i__] * ei; +/* L10: */ + } + + i__1 = *n - 4; + for (i__ = i4 + 1; i__ <= i__1; i__ += 4) { + +/* Drop out of the loop if d(i) <= 0: the matrix is not positive */ +/* definite. */ + + if (d__[i__] <= 0.) { + *info = i__; + goto L30; + } + +/* Solve for e(i) and d(i+1). */ + + ei = e[i__]; + e[i__] = ei / d__[i__]; + d__[i__ + 1] -= e[i__] * ei; + + if (d__[i__ + 1] <= 0.) { + *info = i__ + 1; + goto L30; + } + +/* Solve for e(i+1) and d(i+2). */ + + ei = e[i__ + 1]; + e[i__ + 1] = ei / d__[i__ + 1]; + d__[i__ + 2] -= e[i__ + 1] * ei; + + if (d__[i__ + 2] <= 0.) { + *info = i__ + 2; + goto L30; + } + +/* Solve for e(i+2) and d(i+3). */ + + ei = e[i__ + 2]; + e[i__ + 2] = ei / d__[i__ + 2]; + d__[i__ + 3] -= e[i__ + 2] * ei; + + if (d__[i__ + 3] <= 0.) { + *info = i__ + 3; + goto L30; + } + +/* Solve for e(i+3) and d(i+4). */ + + ei = e[i__ + 3]; + e[i__ + 3] = ei / d__[i__ + 3]; + d__[i__ + 4] -= e[i__ + 3] * ei; +/* L20: */ + } + +/* Check d(n) for positive definiteness. */ + + if (d__[*n] <= 0.) { + *info = *n; + } + +L30: + return 0; + +/* End of DPTTRF */ + +} /* dpttrf_ */ |