#include "blaswrap.h"
#include "f2c.h"

/* Subroutine */ int chpr_(char *uplo, integer *n, real *alpha, complex *x, 
	integer *incx, complex *ap)
{
    /* System generated locals */
    integer i__1, i__2, i__3, i__4, i__5;
    real r__1;
    complex q__1, q__2;
    /* Builtin functions */
    void r_cnjg(complex *, complex *);
    /* Local variables */
    static integer i__, j, k, kk, ix, jx, kx, info;
    static complex temp;
    extern logical lsame_(char *, char *);
    extern /* Subroutine */ int xerbla_(char *, integer *);
/*  Purpose   
    =======   
    CHPR    performs the hermitian rank 1 operation   
       A := alpha*x*conjg( x' ) + A,   
    where alpha is a real scalar, x is an n element vector and A is an   
    n by n hermitian matrix, supplied in packed form.   
    Arguments   
    ==========   
    UPLO   - CHARACTER*1.   
             On entry, UPLO specifies whether the upper or lower   
             triangular part of the matrix A is supplied in the packed   
             array AP as follows:   
                UPLO = 'U' or 'u'   The upper triangular part of A is   
                                    supplied in AP.   
                UPLO = 'L' or 'l'   The lower triangular part of A is   
                                    supplied in AP.   
             Unchanged on exit.   
    N      - INTEGER.   
             On entry, N specifies the order of the matrix A.   
             N must be at least zero.   
             Unchanged on exit.   
    ALPHA  - REAL            .   
             On entry, ALPHA specifies the scalar alpha.   
             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 vector x.   
             Unchanged on exit.   
    INCX   - INTEGER.   
             On entry, INCX specifies the increment for the elements of   
             X. INCX must not be zero.   
             Unchanged on exit.   
    AP     - COMPLEX          array of DIMENSION at least   
             ( ( n*( n + 1 ) )/2 ).   
             Before entry with  UPLO = 'U' or 'u', the array AP must   
             contain the upper triangular part of the hermitian matrix   
             packed sequentially, column by column, so that AP( 1 )   
             contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 )   
             and a( 2, 2 ) respectively, and so on. On exit, the array   
             AP is overwritten by the upper triangular part of the   
             updated matrix.   
             Before entry with UPLO = 'L' or 'l', the array AP must   
             contain the lower triangular part of the hermitian matrix   
             packed sequentially, column by column, so that AP( 1 )   
             contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 )   
             and a( 3, 1 ) respectively, and so on. On exit, the array   
             AP is overwritten by the lower triangular part of the   
             updated matrix.   
             Note that the imaginary parts of the diagonal elements need   
             not be set, they are assumed to be zero, and on exit they   
             are set to zero.   
    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 */
    --ap;
    --x;
    /* Function Body */
    info = 0;
    if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) {
	info = 1;
    } else if (*n < 0) {
	info = 2;
    } else if (*incx == 0) {
	info = 5;
    }
    if (info != 0) {
	xerbla_("CHPR  ", &info);
	return 0;
    }
/*     Quick return if possible. */
    if (*n == 0 || *alpha == 0.f) {
	return 0;
    }
/*     Set the start point in X if the increment is not unity. */
    if (*incx <= 0) {
	kx = 1 - (*n - 1) * *incx;
    } else if (*incx != 1) {
	kx = 1;
    }
/*     Start the operations. In this version the elements of the array AP   
       are accessed sequentially with one pass through AP. */
    kk = 1;
    if (lsame_(uplo, "U")) {
/*        Form  A  when upper triangle is stored in AP. */
	if (*incx == 1) {
	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		i__2 = j;
		if (x[i__2].r != 0.f || x[i__2].i != 0.f) {
		    r_cnjg(&q__2, &x[j]);
		    q__1.r = *alpha * q__2.r, q__1.i = *alpha * q__2.i;
		    temp.r = q__1.r, temp.i = q__1.i;
		    k = kk;
		    i__2 = j - 1;
		    for (i__ = 1; i__ <= i__2; ++i__) {
			i__3 = k;
			i__4 = k;
			i__5 = i__;
			q__2.r = x[i__5].r * temp.r - x[i__5].i * temp.i, 
				q__2.i = x[i__5].r * temp.i + x[i__5].i * 
				temp.r;
			q__1.r = ap[i__4].r + q__2.r, q__1.i = ap[i__4].i + 
				q__2.i;
			ap[i__3].r = q__1.r, ap[i__3].i = q__1.i;
			++k;
/* L10: */
		    }
		    i__2 = kk + j - 1;
		    i__3 = kk + j - 1;
		    i__4 = j;
		    q__1.r = x[i__4].r * temp.r - x[i__4].i * temp.i, q__1.i =
			     x[i__4].r * temp.i + x[i__4].i * temp.r;
		    r__1 = ap[i__3].r + q__1.r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		} else {
		    i__2 = kk + j - 1;
		    i__3 = kk + j - 1;
		    r__1 = ap[i__3].r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		}
		kk += j;
/* L20: */
	    }
	} else {
	    jx = kx;
	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		i__2 = jx;
		if (x[i__2].r != 0.f || x[i__2].i != 0.f) {
		    r_cnjg(&q__2, &x[jx]);
		    q__1.r = *alpha * q__2.r, q__1.i = *alpha * q__2.i;
		    temp.r = q__1.r, temp.i = q__1.i;
		    ix = kx;
		    i__2 = kk + j - 2;
		    for (k = kk; k <= i__2; ++k) {
			i__3 = k;
			i__4 = k;
			i__5 = ix;
			q__2.r = x[i__5].r * temp.r - x[i__5].i * temp.i, 
				q__2.i = x[i__5].r * temp.i + x[i__5].i * 
				temp.r;
			q__1.r = ap[i__4].r + q__2.r, q__1.i = ap[i__4].i + 
				q__2.i;
			ap[i__3].r = q__1.r, ap[i__3].i = q__1.i;
			ix += *incx;
/* L30: */
		    }
		    i__2 = kk + j - 1;
		    i__3 = kk + j - 1;
		    i__4 = jx;
		    q__1.r = x[i__4].r * temp.r - x[i__4].i * temp.i, q__1.i =
			     x[i__4].r * temp.i + x[i__4].i * temp.r;
		    r__1 = ap[i__3].r + q__1.r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		} else {
		    i__2 = kk + j - 1;
		    i__3 = kk + j - 1;
		    r__1 = ap[i__3].r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		}
		jx += *incx;
		kk += j;
/* L40: */
	    }
	}
    } else {
/*        Form  A  when lower triangle is stored in AP. */
	if (*incx == 1) {
	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		i__2 = j;
		if (x[i__2].r != 0.f || x[i__2].i != 0.f) {
		    r_cnjg(&q__2, &x[j]);
		    q__1.r = *alpha * q__2.r, q__1.i = *alpha * q__2.i;
		    temp.r = q__1.r, temp.i = q__1.i;
		    i__2 = kk;
		    i__3 = kk;
		    i__4 = j;
		    q__1.r = temp.r * x[i__4].r - temp.i * x[i__4].i, q__1.i =
			     temp.r * x[i__4].i + temp.i * x[i__4].r;
		    r__1 = ap[i__3].r + q__1.r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		    k = kk + 1;
		    i__2 = *n;
		    for (i__ = j + 1; i__ <= i__2; ++i__) {
			i__3 = k;
			i__4 = k;
			i__5 = i__;
			q__2.r = x[i__5].r * temp.r - x[i__5].i * temp.i, 
				q__2.i = x[i__5].r * temp.i + x[i__5].i * 
				temp.r;
			q__1.r = ap[i__4].r + q__2.r, q__1.i = ap[i__4].i + 
				q__2.i;
			ap[i__3].r = q__1.r, ap[i__3].i = q__1.i;
			++k;
/* L50: */
		    }
		} else {
		    i__2 = kk;
		    i__3 = kk;
		    r__1 = ap[i__3].r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		}
		kk = kk + *n - j + 1;
/* L60: */
	    }
	} else {
	    jx = kx;
	    i__1 = *n;
	    for (j = 1; j <= i__1; ++j) {
		i__2 = jx;
		if (x[i__2].r != 0.f || x[i__2].i != 0.f) {
		    r_cnjg(&q__2, &x[jx]);
		    q__1.r = *alpha * q__2.r, q__1.i = *alpha * q__2.i;
		    temp.r = q__1.r, temp.i = q__1.i;
		    i__2 = kk;
		    i__3 = kk;
		    i__4 = jx;
		    q__1.r = temp.r * x[i__4].r - temp.i * x[i__4].i, q__1.i =
			     temp.r * x[i__4].i + temp.i * x[i__4].r;
		    r__1 = ap[i__3].r + q__1.r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		    ix = jx;
		    i__2 = kk + *n - j;
		    for (k = kk + 1; k <= i__2; ++k) {
			ix += *incx;
			i__3 = k;
			i__4 = k;
			i__5 = ix;
			q__2.r = x[i__5].r * temp.r - x[i__5].i * temp.i, 
				q__2.i = x[i__5].r * temp.i + x[i__5].i * 
				temp.r;
			q__1.r = ap[i__4].r + q__2.r, q__1.i = ap[i__4].i + 
				q__2.i;
			ap[i__3].r = q__1.r, ap[i__3].i = q__1.i;
/* L70: */
		    }
		} else {
		    i__2 = kk;
		    i__3 = kk;
		    r__1 = ap[i__3].r;
		    ap[i__2].r = r__1, ap[i__2].i = 0.f;
		}
		jx += *incx;
		kk = kk + *n - j + 1;
/* L80: */
	    }
	}
    }
    return 0;
/*     End of CHPR  . */
} /* chpr_ */