/* -- translated by f2c (version 19940927).
You must link the resulting object file with the libraries:
-lf2c -lm (in that order)
*/
#include "f2c.h"
/* Subroutine */ int ctrsv_(char *uplo, char *trans, char *diag, integer *n,
complex *a, integer *lda, complex *x, integer *incx)
{
/* System generated locals */
integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5;
complex q__1, q__2, q__3;
/* Builtin functions */
void c_div(complex *, complex *, complex *), r_cnjg(complex *, complex *);
/* Local variables */
static integer info;
static complex temp;
static integer i, j;
extern logical lsame_(char *, char *);
static integer ix, jx, kx;
extern /* Subroutine */ int xerbla_(char *, integer *);
static logical noconj, nounit;
/* Purpose
=======
CTRSV solves one of the systems of equations
A*x = b, or A'*x = b, or conjg( A' )*x = b,
where b and x are n element vectors and A is an n by n unit, or
non-unit, upper or lower triangular matrix.
No test for singularity or near-singularity is included in this
routine. Such tests must be performed before calling this routine.
Parameters
==========
UPLO - CHARACTER*1.
On entry, UPLO specifies whether the matrix is an upper or
lower triangular matrix as follows:
UPLO = 'U' or 'u' A is an upper triangular matrix.
UPLO = 'L' or 'l' A is a lower triangular matrix.
Unchanged on exit.
TRANS - CHARACTER*1.
On entry, TRANS specifies the equations to be solved as
follows:
TRANS = 'N' or 'n' A*x = b.
TRANS = 'T' or 't' A'*x = b.
TRANS = 'C' or 'c' conjg( A' )*x = b.
Unchanged on exit.
DIAG - CHARACTER*1.
On entry, DIAG specifies whether or not A is unit
triangular as follows:
DIAG = 'U' or 'u' A is assumed to be unit triangular.
DIAG = 'N' or 'n' A is not assumed to be unit
triangular.
Unchanged on exit.
N - INTEGER.
On entry, N specifies the order of the matrix A.
N must be at least zero.
Unchanged on exit.
A - COMPLEX array of DIMENSION ( LDA, n ).
Before entry with UPLO = 'U' or 'u', the leading n by n
upper triangular part of the array A must contain the upper
triangular matrix and the strictly lower triangular part of
A is not referenced.
Before entry with UPLO = 'L' or 'l', the leading n by n
lower triangular part of the array A must contain the lower
triangular matrix and the strictly upper triangular part of
A is not referenced.
Note that when DIAG = 'U' or 'u', the diagonal elements of
A are not referenced either, but are assumed to be unity.
Unchanged on exit.
LDA - INTEGER.
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. LDA must be at least
max( 1, n ).
Unchanged on exit.
X - COMPLEX array of dimension at least
( 1 + ( n - 1 )*abs( INCX ) ).
Before entry, the incremented array X must contain the n
element right-hand side vector b. On exit, X is overwritten
with the solution vector x.
INCX - INTEGER.
On entry, INCX specifies the increment for the elements of
X. INCX must not be zero.
Unchanged on exit.
Level 2 Blas routine.
-- Written on 22-October-1986.
Jack Dongarra, Argonne National Lab.
Jeremy Du Croz, Nag Central Office.
Sven Hammarling, Nag Central Office.
Richard Hanson, Sandia National Labs.
Test the input parameters.
Parameter adjustments
Function Body */
#define X(I) x[(I)-1]
#define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]
info = 0;
if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
info = 1;
} else if (! lsame_(trans, "N") && ! lsame_(trans, "T") &&
! lsame_(trans, "C")) {
info = 2;
} else if (! lsame_(diag, "U") && ! lsame_(diag, "N")) {
info = 3;
} else if (*n < 0) {
info = 4;
} else if (*lda < max(1,*n)) {
info = 6;
} else if (*incx == 0) {
info = 8;
}
if (info != 0) {
xerbla_("CTRSV ", &info);
return 0;
}
/* Quick return if possible. */
if (*n == 0) {
return 0;
}
noconj = lsame_(trans, "T");
nounit = lsame_(diag, "N");
/* Set up the start point in X if the increment is not unity. This
will be ( N - 1 )*INCX too small for descending loops. */
if (*incx <= 0) {
kx = 1 - (*n - 1) * *incx;
} else if (*incx != 1) {
kx = 1;
}
/* Start the operations. In this version the elements of A are
accessed sequentially with one pass through A. */
if (lsame_(trans, "N")) {
/* Form x := inv( A )*x. */
if (lsame_(uplo, "U")) {
if (*incx == 1) {
for (j = *n; j >= 1; --j) {
i__1 = j;
if (X(j).r != 0.f || X(j).i != 0.f) {
if (nounit) {
i__1 = j;
c_div(&q__1, &X(j), &A(j,j));
X(j).r = q__1.r, X(j).i = q__1.i;
}
i__1 = j;
temp.r = X(j).r, temp.i = X(j).i;
for (i = j - 1; i >= 1; --i) {
i__1 = i;
i__2 = i;
i__3 = i + j * a_dim1;
q__2.r = temp.r * A(i,j).r - temp.i * A(i,j).i,
q__2.i = temp.r * A(i,j).i + temp.i * A(i,j).r;
q__1.r = X(i).r - q__2.r, q__1.i = X(i).i -
q__2.i;
X(i).r = q__1.r, X(i).i = q__1.i;
/* L10: */
}
}
/* L20: */
}
} else {
jx = kx + (*n - 1) * *incx;
for (j = *n; j >= 1; --j) {
i__1 = jx;
if (X(jx).r != 0.f || X(jx).i != 0.f) {
if (nounit) {
i__1 = jx;
c_div(&q__1, &X(jx), &A(j,j));
X(jx).r = q__1.r, X(jx).i = q__1.i;
}
i__1 = jx;
temp.r = X(jx).r, temp.i = X(jx).i;
ix = jx;
for (i = j - 1; i >= 1; --i) {
ix -= *incx;
i__1 = ix;
i__2 = ix;
i__3 = i + j * a_dim1;
q__2.r = temp.r * A(i,j).r - temp.i * A(i,j).i,
q__2.i = temp.r * A(i,j).i + temp.i * A(i,j).r;
q__1.r = X(ix).r - q__2.r, q__1.i = X(ix).i -
q__2.i;
X(ix).r = q__1.r, X(ix).i = q__1.i;
/* L30: */
}
}
jx -= *incx;
/* L40: */
}
}
} else {
if (*incx == 1) {
i__1 = *n;
for (j = 1; j <= *n; ++j) {
i__2 = j;
if (X(j).r != 0.f || X(j).i != 0.f) {
if (nounit) {
i__2 = j;
c_div(&q__1, &X(j), &A(j,j));
X(j).r = q__1.r, X(j).i = q__1.i;
}
i__2 = j;
temp.r = X(j).r, temp.i = X(j).i;
i__2 = *n;
for (i = j + 1; i <= *n; ++i) {
i__3 = i;
i__4 = i;
i__5 = i + j * a_dim1;
q__2.r = temp.r * A(i,j).r - temp.i * A(i,j).i,
q__2.i = temp.r * A(i,j).i + temp.i * A(i,j).r;
q__1.r = X(i).r - q__2.r, q__1.i = X(i).i -
q__2.i;
X(i).r = q__1.r, X(i).i = q__1.i;
/* L50: */
}
}
/* L60: */
}
} else {
jx = kx;
i__1 = *n;
for (j = 1; j <= *n; ++j) {
i__2 = jx;
if (X(jx).r != 0.f || X(jx).i != 0.f) {
if (nounit) {
i__2 = jx;
c_div(&q__1, &X(jx), &A(j,j));
X(jx).r = q__1.r, X(jx).i = q__1.i;
}
i__2 = jx;
temp.r = X(jx).r, temp.i = X(jx).i;
ix = jx;
i__2 = *n;
for (i = j + 1; i <= *n; ++i) {
ix += *incx;
i__3 = ix;
i__4 = ix;
i__5 = i + j * a_dim1;
q__2.r = temp.r * A(i,j).r - temp.i * A(i,j).i,
q__2.i = temp.r * A(i,j).i + temp.i * A(i,j).r;
q__1.r = X(ix).r - q__2.r, q__1.i = X(ix).i -
q__2.i;
X(ix).r = q__1.r, X(ix).i = q__1.i;
/* L70: */
}
}
jx += *incx;
/* L80: */
}
}
}
} else {
/* Form x := inv( A' )*x or x := inv( conjg( A' ) )*x. */
if (lsame_(uplo, "U")) {
if (*incx == 1) {
i__1 = *n;
for (j = 1; j <= *n; ++j) {
i__2 = j;
temp.r = X(j).r, temp.i = X(j).i;
if (noconj) {
i__2 = j - 1;
for (i = 1; i <= j-1; ++i) {
i__3 = i + j * a_dim1;
i__4 = i;
q__2.r = A(i,j).r * X(i).r - A(i,j).i * X(
i).i, q__2.i = A(i,j).r * X(i).i +
A(i,j).i * X(i).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
/* L90: */
}
if (nounit) {
c_div(&q__1, &temp, &A(j,j));
temp.r = q__1.r, temp.i = q__1.i;
}
} else {
i__2 = j - 1;
for (i = 1; i <= j-1; ++i) {
r_cnjg(&q__3, &A(i,j));
i__3 = i;
q__2.r = q__3.r * X(i).r - q__3.i * X(i).i,
q__2.i = q__3.r * X(i).i + q__3.i * X(
i).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
/* L100: */
}
if (nounit) {
r_cnjg(&q__2, &A(j,j));
c_div(&q__1, &temp, &q__2);
temp.r = q__1.r, temp.i = q__1.i;
}
}
i__2 = j;
X(j).r = temp.r, X(j).i = temp.i;
/* L110: */
}
} else {
jx = kx;
i__1 = *n;
for (j = 1; j <= *n; ++j) {
ix = kx;
i__2 = jx;
temp.r = X(jx).r, temp.i = X(jx).i;
if (noconj) {
i__2 = j - 1;
for (i = 1; i <= j-1; ++i) {
i__3 = i + j * a_dim1;
i__4 = ix;
q__2.r = A(i,j).r * X(ix).r - A(i,j).i * X(
ix).i, q__2.i = A(i,j).r * X(ix).i +
A(i,j).i * X(ix).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
ix += *incx;
/* L120: */
}
if (nounit) {
c_div(&q__1, &temp, &A(j,j));
temp.r = q__1.r, temp.i = q__1.i;
}
} else {
i__2 = j - 1;
for (i = 1; i <= j-1; ++i) {
r_cnjg(&q__3, &A(i,j));
i__3 = ix;
q__2.r = q__3.r * X(ix).r - q__3.i * X(ix).i,
q__2.i = q__3.r * X(ix).i + q__3.i * X(
ix).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
ix += *incx;
/* L130: */
}
if (nounit) {
r_cnjg(&q__2, &A(j,j));
c_div(&q__1, &temp, &q__2);
temp.r = q__1.r, temp.i = q__1.i;
}
}
i__2 = jx;
X(jx).r = temp.r, X(jx).i = temp.i;
jx += *incx;
/* L140: */
}
}
} else {
if (*incx == 1) {
for (j = *n; j >= 1; --j) {
i__1 = j;
temp.r = X(j).r, temp.i = X(j).i;
if (noconj) {
i__1 = j + 1;
for (i = *n; i >= j+1; --i) {
i__2 = i + j * a_dim1;
i__3 = i;
q__2.r = A(i,j).r * X(i).r - A(i,j).i * X(
i).i, q__2.i = A(i,j).r * X(i).i +
A(i,j).i * X(i).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
/* L150: */
}
if (nounit) {
c_div(&q__1, &temp, &A(j,j));
temp.r = q__1.r, temp.i = q__1.i;
}
} else {
i__1 = j + 1;
for (i = *n; i >= j+1; --i) {
r_cnjg(&q__3, &A(i,j));
i__2 = i;
q__2.r = q__3.r * X(i).r - q__3.i * X(i).i,
q__2.i = q__3.r * X(i).i + q__3.i * X(
i).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
/* L160: */
}
if (nounit) {
r_cnjg(&q__2, &A(j,j));
c_div(&q__1, &temp, &q__2);
temp.r = q__1.r, temp.i = q__1.i;
}
}
i__1 = j;
X(j).r = temp.r, X(j).i = temp.i;
/* L170: */
}
} else {
kx += (*n - 1) * *incx;
jx = kx;
for (j = *n; j >= 1; --j) {
ix = kx;
i__1 = jx;
temp.r = X(jx).r, temp.i = X(jx).i;
if (noconj) {
i__1 = j + 1;
for (i = *n; i >= j+1; --i) {
i__2 = i + j * a_dim1;
i__3 = ix;
q__2.r = A(i,j).r * X(ix).r - A(i,j).i * X(
ix).i, q__2.i = A(i,j).r * X(ix).i +
A(i,j).i * X(ix).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
ix -= *incx;
/* L180: */
}
if (nounit) {
c_div(&q__1, &temp, &A(j,j));
temp.r = q__1.r, temp.i = q__1.i;
}
} else {
i__1 = j + 1;
for (i = *n; i >= j+1; --i) {
r_cnjg(&q__3, &A(i,j));
i__2 = ix;
q__2.r = q__3.r * X(ix).r - q__3.i * X(ix).i,
q__2.i = q__3.r * X(ix).i + q__3.i * X(
ix).r;
q__1.r = temp.r - q__2.r, q__1.i = temp.i -
q__2.i;
temp.r = q__1.r, temp.i = q__1.i;
ix -= *incx;
/* L190: */
}
if (nounit) {
r_cnjg(&q__2, &A(j,j));
c_div(&q__1, &temp, &q__2);
temp.r = q__1.r, temp.i = q__1.i;
}
}
i__1 = jx;
X(jx).r = temp.r, X(jx).i = temp.i;
jx -= *incx;
/* L200: */
}
}
}
}
return 0;
/* End of CTRSV . */
} /* ctrsv_ */