#include "blaswrap.h" /* csbmv.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" /* Subroutine */ int csbmv_(char *uplo, integer *n, integer *k, complex * alpha, complex *a, integer *lda, complex *x, integer *incx, complex * beta, complex *y, integer *incy) { /* 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, q__4; /* Local variables */ static integer i__, j, l, ix, iy, jx, jy, kx, ky, info; static complex temp1, temp2; extern logical lsame_(char *, char *); static integer kplus1; extern /* Subroutine */ int xerbla_(char *, integer *); /* -- LAPACK auxiliary routine (version 3.1) -- Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. November 2006 Purpose ======= CSBMV performs the matrix-vector operation y := alpha*A*x + beta*y, where alpha and beta are scalars, x and y are n element vectors and A is an n by n symmetric band matrix, with k super-diagonals. Arguments ========== UPLO - CHARACTER*1 On entry, UPLO specifies whether the upper or lower triangular part of the band matrix A is being supplied as follows: UPLO = 'U' or 'u' The upper triangular part of A is being supplied. UPLO = 'L' or 'l' The lower triangular part of A is being supplied. Unchanged on exit. N - INTEGER On entry, N specifies the order of the matrix A. N must be at least zero. Unchanged on exit. K - INTEGER On entry, K specifies the number of super-diagonals of the matrix A. K must satisfy 0 .le. K. Unchanged on exit. ALPHA - COMPLEX On entry, ALPHA specifies the scalar alpha. Unchanged on exit. A - COMPLEX array, dimension( LDA, N ) Before entry with UPLO = 'U' or 'u', the leading ( k + 1 ) by n part of the array A must contain the upper triangular band part of the symmetric matrix, supplied column by column, with the leading diagonal of the matrix in row ( k + 1 ) of the array, the first super-diagonal starting at position 2 in row k, and so on. The top left k by k triangle of the array A is not referenced. The following program segment will transfer the upper triangular part of a symmetric band matrix from conventional full matrix storage to band storage: DO 20, J = 1, N M = K + 1 - J DO 10, I = MAX( 1, J - K ), J A( M + I, J ) = matrix( I, J ) 10 CONTINUE 20 CONTINUE Before entry with UPLO = 'L' or 'l', the leading ( k + 1 ) by n part of the array A must contain the lower triangular band part of the symmetric matrix, supplied column by column, with the leading diagonal of the matrix in row 1 of the array, the first sub-diagonal starting at position 1 in row 2, and so on. The bottom right k by k triangle of the array A is not referenced. The following program segment will transfer the lower triangular part of a symmetric band matrix from conventional full matrix storage to band storage: DO 20, J = 1, N M = 1 - J DO 10, I = J, MIN( N, J + K ) A( M + I, J ) = matrix( I, J ) 10 CONTINUE 20 CONTINUE 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 ( k + 1 ). Unchanged on exit. X - COMPLEX array, dimension at least ( 1 + ( N - 1 )*abs( INCX ) ). Before entry, the incremented array X must contain the 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. BETA - COMPLEX On entry, BETA specifies the scalar beta. Unchanged on exit. Y - COMPLEX array, dimension at least ( 1 + ( N - 1 )*abs( INCY ) ). Before entry, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y. INCY - INTEGER On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Unchanged on exit. ===================================================================== Test the input parameters. Parameter adjustments */ a_dim1 = *lda; a_offset = 1 + a_dim1; a -= a_offset; --x; --y; /* Function Body */ info = 0; if (! lsame_(uplo, "U") && ! lsame_(uplo, "L")) { info = 1; } else if (*n < 0) { info = 2; } else if (*k < 0) { info = 3; } else if (*lda < *k + 1) { info = 6; } else if (*incx == 0) { info = 8; } else if (*incy == 0) { info = 11; } if (info != 0) { xerbla_("CSBMV ", &info); return 0; } /* Quick return if possible. */ if (*n == 0 || alpha->r == 0.f && alpha->i == 0.f && (beta->r == 1.f && beta->i == 0.f)) { return 0; } /* Set up the start points in X and Y. */ if (*incx > 0) { kx = 1; } else { kx = 1 - (*n - 1) * *incx; } if (*incy > 0) { ky = 1; } else { ky = 1 - (*n - 1) * *incy; } /* Start the operations. In this version the elements of the array A are accessed sequentially with one pass through A. First form y := beta*y. */ if (beta->r != 1.f || beta->i != 0.f) { if (*incy == 1) { if (beta->r == 0.f && beta->i == 0.f) { i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { i__2 = i__; y[i__2].r = 0.f, y[i__2].i = 0.f; /* L10: */ } } else { i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { i__2 = i__; i__3 = i__; q__1.r = beta->r * y[i__3].r - beta->i * y[i__3].i, q__1.i = beta->r * y[i__3].i + beta->i * y[i__3] .r; y[i__2].r = q__1.r, y[i__2].i = q__1.i; /* L20: */ } } } else { iy = ky; if (beta->r == 0.f && beta->i == 0.f) { i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { i__2 = iy; y[i__2].r = 0.f, y[i__2].i = 0.f; iy += *incy; /* L30: */ } } else { i__1 = *n; for (i__ = 1; i__ <= i__1; ++i__) { i__2 = iy; i__3 = iy; q__1.r = beta->r * y[i__3].r - beta->i * y[i__3].i, q__1.i = beta->r * y[i__3].i + beta->i * y[i__3] .r; y[i__2].r = q__1.r, y[i__2].i = q__1.i; iy += *incy; /* L40: */ } } } } if (alpha->r == 0.f && alpha->i == 0.f) { return 0; } if (lsame_(uplo, "U")) { /* Form y when upper triangle of A is stored. */ kplus1 = *k + 1; if (*incx == 1 && *incy == 1) { i__1 = *n; for (j = 1; j <= i__1; ++j) { i__2 = j; q__1.r = alpha->r * x[i__2].r - alpha->i * x[i__2].i, q__1.i = alpha->r * x[i__2].i + alpha->i * x[i__2].r; temp1.r = q__1.r, temp1.i = q__1.i; temp2.r = 0.f, temp2.i = 0.f; l = kplus1 - j; /* Computing MAX */ i__2 = 1, i__3 = j - *k; i__4 = j - 1; for (i__ = max(i__2,i__3); i__ <= i__4; ++i__) { i__2 = i__; i__3 = i__; i__5 = l + i__ + j * a_dim1; q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i, q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5] .r; q__1.r = y[i__3].r + q__2.r, q__1.i = y[i__3].i + q__2.i; y[i__2].r = q__1.r, y[i__2].i = q__1.i; i__2 = l + i__ + j * a_dim1; i__3 = i__; q__2.r = a[i__2].r * x[i__3].r - a[i__2].i * x[i__3].i, q__2.i = a[i__2].r * x[i__3].i + a[i__2].i * x[ i__3].r; q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i; temp2.r = q__1.r, temp2.i = q__1.i; /* L50: */ } i__4 = j; i__2 = j; i__3 = kplus1 + j * a_dim1; q__3.r = temp1.r * a[i__3].r - temp1.i * a[i__3].i, q__3.i = temp1.r * a[i__3].i + temp1.i * a[i__3].r; q__2.r = y[i__2].r + q__3.r, q__2.i = y[i__2].i + q__3.i; q__4.r = alpha->r * temp2.r - alpha->i * temp2.i, q__4.i = alpha->r * temp2.i + alpha->i * temp2.r; q__1.r = q__2.r + q__4.r, q__1.i = q__2.i + q__4.i; y[i__4].r = q__1.r, y[i__4].i = q__1.i; /* L60: */ } } else { jx = kx; jy = ky; i__1 = *n; for (j = 1; j <= i__1; ++j) { i__4 = jx; q__1.r = alpha->r * x[i__4].r - alpha->i * x[i__4].i, q__1.i = alpha->r * x[i__4].i + alpha->i * x[i__4].r; temp1.r = q__1.r, temp1.i = q__1.i; temp2.r = 0.f, temp2.i = 0.f; ix = kx; iy = ky; l = kplus1 - j; /* Computing MAX */ i__4 = 1, i__2 = j - *k; i__3 = j - 1; for (i__ = max(i__4,i__2); i__ <= i__3; ++i__) { i__4 = iy; i__2 = iy; i__5 = l + i__ + j * a_dim1; q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i, q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5] .r; q__1.r = y[i__2].r + q__2.r, q__1.i = y[i__2].i + q__2.i; y[i__4].r = q__1.r, y[i__4].i = q__1.i; i__4 = l + i__ + j * a_dim1; i__2 = ix; q__2.r = a[i__4].r * x[i__2].r - a[i__4].i * x[i__2].i, q__2.i = a[i__4].r * x[i__2].i + a[i__4].i * x[ i__2].r; q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i; temp2.r = q__1.r, temp2.i = q__1.i; ix += *incx; iy += *incy; /* L70: */ } i__3 = jy; i__4 = jy; i__2 = kplus1 + j * a_dim1; q__3.r = temp1.r * a[i__2].r - temp1.i * a[i__2].i, q__3.i = temp1.r * a[i__2].i + temp1.i * a[i__2].r; q__2.r = y[i__4].r + q__3.r, q__2.i = y[i__4].i + q__3.i; q__4.r = alpha->r * temp2.r - alpha->i * temp2.i, q__4.i = alpha->r * temp2.i + alpha->i * temp2.r; q__1.r = q__2.r + q__4.r, q__1.i = q__2.i + q__4.i; y[i__3].r = q__1.r, y[i__3].i = q__1.i; jx += *incx; jy += *incy; if (j > *k) { kx += *incx; ky += *incy; } /* L80: */ } } } else { /* Form y when lower triangle of A is stored. */ if (*incx == 1 && *incy == 1) { i__1 = *n; for (j = 1; j <= i__1; ++j) { i__3 = j; q__1.r = alpha->r * x[i__3].r - alpha->i * x[i__3].i, q__1.i = alpha->r * x[i__3].i + alpha->i * x[i__3].r; temp1.r = q__1.r, temp1.i = q__1.i; temp2.r = 0.f, temp2.i = 0.f; i__3 = j; i__4 = j; i__2 = j * a_dim1 + 1; q__2.r = temp1.r * a[i__2].r - temp1.i * a[i__2].i, q__2.i = temp1.r * a[i__2].i + temp1.i * a[i__2].r; q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i; y[i__3].r = q__1.r, y[i__3].i = q__1.i; l = 1 - j; /* Computing MIN */ i__4 = *n, i__2 = j + *k; i__3 = min(i__4,i__2); for (i__ = j + 1; i__ <= i__3; ++i__) { i__4 = i__; i__2 = i__; i__5 = l + i__ + j * a_dim1; q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i, q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5] .r; q__1.r = y[i__2].r + q__2.r, q__1.i = y[i__2].i + q__2.i; y[i__4].r = q__1.r, y[i__4].i = q__1.i; i__4 = l + i__ + j * a_dim1; i__2 = i__; q__2.r = a[i__4].r * x[i__2].r - a[i__4].i * x[i__2].i, q__2.i = a[i__4].r * x[i__2].i + a[i__4].i * x[ i__2].r; q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i; temp2.r = q__1.r, temp2.i = q__1.i; /* L90: */ } i__3 = j; i__4 = j; q__2.r = alpha->r * temp2.r - alpha->i * temp2.i, q__2.i = alpha->r * temp2.i + alpha->i * temp2.r; q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i; y[i__3].r = q__1.r, y[i__3].i = q__1.i; /* L100: */ } } else { jx = kx; jy = ky; i__1 = *n; for (j = 1; j <= i__1; ++j) { i__3 = jx; q__1.r = alpha->r * x[i__3].r - alpha->i * x[i__3].i, q__1.i = alpha->r * x[i__3].i + alpha->i * x[i__3].r; temp1.r = q__1.r, temp1.i = q__1.i; temp2.r = 0.f, temp2.i = 0.f; i__3 = jy; i__4 = jy; i__2 = j * a_dim1 + 1; q__2.r = temp1.r * a[i__2].r - temp1.i * a[i__2].i, q__2.i = temp1.r * a[i__2].i + temp1.i * a[i__2].r; q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i; y[i__3].r = q__1.r, y[i__3].i = q__1.i; l = 1 - j; ix = jx; iy = jy; /* Computing MIN */ i__4 = *n, i__2 = j + *k; i__3 = min(i__4,i__2); for (i__ = j + 1; i__ <= i__3; ++i__) { ix += *incx; iy += *incy; i__4 = iy; i__2 = iy; i__5 = l + i__ + j * a_dim1; q__2.r = temp1.r * a[i__5].r - temp1.i * a[i__5].i, q__2.i = temp1.r * a[i__5].i + temp1.i * a[i__5] .r; q__1.r = y[i__2].r + q__2.r, q__1.i = y[i__2].i + q__2.i; y[i__4].r = q__1.r, y[i__4].i = q__1.i; i__4 = l + i__ + j * a_dim1; i__2 = ix; q__2.r = a[i__4].r * x[i__2].r - a[i__4].i * x[i__2].i, q__2.i = a[i__4].r * x[i__2].i + a[i__4].i * x[ i__2].r; q__1.r = temp2.r + q__2.r, q__1.i = temp2.i + q__2.i; temp2.r = q__1.r, temp2.i = q__1.i; /* L110: */ } i__3 = jy; i__4 = jy; q__2.r = alpha->r * temp2.r - alpha->i * temp2.i, q__2.i = alpha->r * temp2.i + alpha->i * temp2.r; q__1.r = y[i__4].r + q__2.r, q__1.i = y[i__4].i + q__2.i; y[i__3].r = q__1.r, y[i__3].i = q__1.i; jx += *incx; jy += *incy; /* L120: */ } } } return 0; /* End of CSBMV */ } /* csbmv_ */