ztptrs.c
Go to the documentation of this file.
00001 /* ztptrs.f -- translated by f2c (version 20061008).
00002    You must link the resulting object file with libf2c:
00003         on Microsoft Windows system, link with libf2c.lib;
00004         on Linux or Unix systems, link with .../path/to/libf2c.a -lm
00005         or, if you install libf2c.a in a standard place, with -lf2c -lm
00006         -- in that order, at the end of the command line, as in
00007                 cc *.o -lf2c -lm
00008         Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
00009 
00010                 http://www.netlib.org/f2c/libf2c.zip
00011 */
00012 
00013 #include "f2c.h"
00014 #include "blaswrap.h"
00015 
00016 /* Table of constant values */
00017 
00018 static integer c__1 = 1;
00019 
00020 /* Subroutine */ int ztptrs_(char *uplo, char *trans, char *diag, integer *n, 
00021         integer *nrhs, doublecomplex *ap, doublecomplex *b, integer *ldb, 
00022         integer *info)
00023 {
00024     /* System generated locals */
00025     integer b_dim1, b_offset, i__1, i__2;
00026 
00027     /* Local variables */
00028     integer j, jc;
00029     extern logical lsame_(char *, char *);
00030     logical upper;
00031     extern /* Subroutine */ int ztpsv_(char *, char *, char *, integer *, 
00032             doublecomplex *, doublecomplex *, integer *), xerbla_(char *, integer *);
00033     logical nounit;
00034 
00035 
00036 /*  -- LAPACK routine (version 3.2) -- */
00037 /*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
00038 /*     November 2006 */
00039 
00040 /*     .. Scalar Arguments .. */
00041 /*     .. */
00042 /*     .. Array Arguments .. */
00043 /*     .. */
00044 
00045 /*  Purpose */
00046 /*  ======= */
00047 
00048 /*  ZTPTRS solves a triangular system of the form */
00049 
00050 /*     A * X = B,  A**T * X = B,  or  A**H * X = B, */
00051 
00052 /*  where A is a triangular matrix of order N stored in packed format, */
00053 /*  and B is an N-by-NRHS matrix.  A check is made to verify that A is */
00054 /*  nonsingular. */
00055 
00056 /*  Arguments */
00057 /*  ========= */
00058 
00059 /*  UPLO    (input) CHARACTER*1 */
00060 /*          = 'U':  A is upper triangular; */
00061 /*          = 'L':  A is lower triangular. */
00062 
00063 /*  TRANS   (input) CHARACTER*1 */
00064 /*          Specifies the form of the system of equations: */
00065 /*          = 'N':  A * X = B     (No transpose) */
00066 /*          = 'T':  A**T * X = B  (Transpose) */
00067 /*          = 'C':  A**H * X = B  (Conjugate transpose) */
00068 
00069 /*  DIAG    (input) CHARACTER*1 */
00070 /*          = 'N':  A is non-unit triangular; */
00071 /*          = 'U':  A is unit triangular. */
00072 
00073 /*  N       (input) INTEGER */
00074 /*          The order of the matrix A.  N >= 0. */
00075 
00076 /*  NRHS    (input) INTEGER */
00077 /*          The number of right hand sides, i.e., the number of columns */
00078 /*          of the matrix B.  NRHS >= 0. */
00079 
00080 /*  AP      (input) COMPLEX*16 array, dimension (N*(N+1)/2) */
00081 /*          The upper or lower triangular matrix A, packed columnwise in */
00082 /*          a linear array.  The j-th column of A is stored in the array */
00083 /*          AP as follows: */
00084 /*          if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; */
00085 /*          if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n. */
00086 
00087 /*  B       (input/output) COMPLEX*16 array, dimension (LDB,NRHS) */
00088 /*          On entry, the right hand side matrix B. */
00089 /*          On exit, if INFO = 0, the solution matrix X. */
00090 
00091 /*  LDB     (input) INTEGER */
00092 /*          The leading dimension of the array B.  LDB >= max(1,N). */
00093 
00094 /*  INFO    (output) INTEGER */
00095 /*          = 0:  successful exit */
00096 /*          < 0:  if INFO = -i, the i-th argument had an illegal value */
00097 /*          > 0:  if INFO = i, the i-th diagonal element of A is zero, */
00098 /*                indicating that the matrix is singular and the */
00099 /*                solutions X have not been computed. */
00100 
00101 /*  ===================================================================== */
00102 
00103 /*     .. Parameters .. */
00104 /*     .. */
00105 /*     .. Local Scalars .. */
00106 /*     .. */
00107 /*     .. External Functions .. */
00108 /*     .. */
00109 /*     .. External Subroutines .. */
00110 /*     .. */
00111 /*     .. Intrinsic Functions .. */
00112 /*     .. */
00113 /*     .. Executable Statements .. */
00114 
00115 /*     Test the input parameters. */
00116 
00117     /* Parameter adjustments */
00118     --ap;
00119     b_dim1 = *ldb;
00120     b_offset = 1 + b_dim1;
00121     b -= b_offset;
00122 
00123     /* Function Body */
00124     *info = 0;
00125     upper = lsame_(uplo, "U");
00126     nounit = lsame_(diag, "N");
00127     if (! upper && ! lsame_(uplo, "L")) {
00128         *info = -1;
00129     } else if (! lsame_(trans, "N") && ! lsame_(trans, 
00130             "T") && ! lsame_(trans, "C")) {
00131         *info = -2;
00132     } else if (! nounit && ! lsame_(diag, "U")) {
00133         *info = -3;
00134     } else if (*n < 0) {
00135         *info = -4;
00136     } else if (*nrhs < 0) {
00137         *info = -5;
00138     } else if (*ldb < max(1,*n)) {
00139         *info = -8;
00140     }
00141     if (*info != 0) {
00142         i__1 = -(*info);
00143         xerbla_("ZTPTRS", &i__1);
00144         return 0;
00145     }
00146 
00147 /*     Quick return if possible */
00148 
00149     if (*n == 0) {
00150         return 0;
00151     }
00152 
00153 /*     Check for singularity. */
00154 
00155     if (nounit) {
00156         if (upper) {
00157             jc = 1;
00158             i__1 = *n;
00159             for (*info = 1; *info <= i__1; ++(*info)) {
00160                 i__2 = jc + *info - 1;
00161                 if (ap[i__2].r == 0. && ap[i__2].i == 0.) {
00162                     return 0;
00163                 }
00164                 jc += *info;
00165 /* L10: */
00166             }
00167         } else {
00168             jc = 1;
00169             i__1 = *n;
00170             for (*info = 1; *info <= i__1; ++(*info)) {
00171                 i__2 = jc;
00172                 if (ap[i__2].r == 0. && ap[i__2].i == 0.) {
00173                     return 0;
00174                 }
00175                 jc = jc + *n - *info + 1;
00176 /* L20: */
00177             }
00178         }
00179     }
00180     *info = 0;
00181 
00182 /*     Solve  A * x = b,  A**T * x = b,  or  A**H * x = b. */
00183 
00184     i__1 = *nrhs;
00185     for (j = 1; j <= i__1; ++j) {
00186         ztpsv_(uplo, trans, diag, n, &ap[1], &b[j * b_dim1 + 1], &c__1);
00187 /* L30: */
00188     }
00189 
00190     return 0;
00191 
00192 /*     End of ZTPTRS */
00193 
00194 } /* ztptrs_ */


swiftnav
Author(s):
autogenerated on Sat Jun 8 2019 18:56:44