slascl.c

/* slascl.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 "clapack.h"


/* Subroutine */ int slascl_(char *type__, integer *kl, integer *ku, real *
	cfrom, real *cto, integer *m, integer *n, real *a, integer *lda, 
	integer *info)
{
    /* System generated locals */
    integer a_dim1, a_offset, i__1, i__2, i__3, i__4, i__5;

    /* Local variables */
    integer i__, j, k1, k2, k3, k4;
    real mul, cto1;
    logical done;
    real ctoc;
    extern logical lsame_(char *, char *);
    integer itype;
    real cfrom1;
    extern doublereal slamch_(char *);
    real cfromc;
    extern /* Subroutine */ int xerbla_(char *, integer *);
    real bignum;
    extern logical sisnan_(real *);
    real smlnum;


/*  -- LAPACK auxiliary routine (version 3.2) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  SLASCL multiplies the M by N real matrix A by the real scalar */
/*  CTO/CFROM.  This is done without over/underflow as long as the final */
/*  result CTO*A(I,J)/CFROM does not over/underflow. TYPE specifies that */
/*  A may be full, upper triangular, lower triangular, upper Hessenberg, */
/*  or banded. */

/*  Arguments */
/*  ========= */

/*  TYPE    (input) CHARACTER*1 */
/*          TYPE indices the storage type of the input matrix. */
/*          = 'G':  A is a full matrix. */
/*          = 'L':  A is a lower triangular matrix. */
/*          = 'U':  A is an upper triangular matrix. */
/*          = 'H':  A is an upper Hessenberg matrix. */
/*          = 'B':  A is a symmetric band matrix with lower bandwidth KL */
/*                  and upper bandwidth KU and with the only the lower */
/*                  half stored. */
/*          = 'Q':  A is a symmetric band matrix with lower bandwidth KL */
/*                  and upper bandwidth KU and with the only the upper */
/*                  half stored. */
/*          = 'Z':  A is a band matrix with lower bandwidth KL and upper */
/*                  bandwidth KU. */

/*  KL      (input) INTEGER */
/*          The lower bandwidth of A.  Referenced only if TYPE = 'B', */
/*          'Q' or 'Z'. */

/*  KU      (input) INTEGER */
/*          The upper bandwidth of A.  Referenced only if TYPE = 'B', */
/*          'Q' or 'Z'. */

/*  CFROM   (input) REAL */
/*  CTO     (input) REAL */
/*          The matrix A is multiplied by CTO/CFROM. A(I,J) is computed */
/*          without over/underflow if the final result CTO*A(I,J)/CFROM */
/*          can be represented without over/underflow.  CFROM must be */
/*          nonzero. */

/*  M       (input) INTEGER */
/*          The number of rows of the matrix A.  M >= 0. */

/*  N       (input) INTEGER */
/*          The number of columns of the matrix A.  N >= 0. */

/*  A       (input/output) REAL array, dimension (LDA,N) */
/*          The matrix to be multiplied by CTO/CFROM.  See TYPE for the */
/*          storage type. */

/*  LDA     (input) INTEGER */
/*          The leading dimension of the array A.  LDA >= max(1,M). */

/*  INFO    (output) INTEGER */
/*          0  - successful exit */
/*          <0 - if INFO = -i, the i-th argument had an illegal value. */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. Intrinsic Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Test the input arguments */

    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;

    /* Function Body */
    *info = 0;

    if (lsame_(type__, "G")) {
	itype = 0;
    } else if (lsame_(type__, "L")) {
	itype = 1;
    } else if (lsame_(type__, "U")) {
	itype = 2;
    } else if (lsame_(type__, "H")) {
	itype = 3;
    } else if (lsame_(type__, "B")) {
	itype = 4;
    } else if (lsame_(type__, "Q")) {
	itype = 5;
    } else if (lsame_(type__, "Z")) {
	itype = 6;
    } else {
	itype = -1;
    }

    if (itype == -1) {
	*info = -1;
    } else if (*cfrom == 0.f || sisnan_(cfrom)) {
	*info = -4;
    } else if (sisnan_(cto)) {
	*info = -5;
    } else if (*m < 0) {
	*info = -6;
    } else if (*n < 0 || itype == 4 && *n != *m || itype == 5 && *n != *m) {
	*info = -7;
    } else if (itype <= 3 && *lda < max(1,*m)) {
	*info = -9;
    } else if (itype >= 4) {
/* Computing MAX */
	i__1 = *m - 1;
	if (*kl < 0 || *kl > max(i__1,0)) {
	    *info = -2;
	} else /* if(complicated condition) */ {
/* Computing MAX */
	    i__1 = *n - 1;
	    if (*ku < 0 || *ku > max(i__1,0) || (itype == 4 || itype == 5) && 
		    *kl != *ku) {
		*info = -3;
	    } else if (itype == 4 && *lda < *kl + 1 || itype == 5 && *lda < *
		    ku + 1 || itype == 6 && *lda < (*kl << 1) + *ku + 1) {
		*info = -9;
	    }
	}
    }

    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("SLASCL", &i__1);
	return 0;
    }

/*     Quick return if possible */

    if (*n == 0 || *m == 0) {
	return 0;
    }

/*     Get machine parameters */

    smlnum = slamch_("S");
    bignum = 1.f / smlnum;

    cfromc = *cfrom;
    ctoc = *cto;

L10:
    cfrom1 = cfromc * smlnum;
    if (cfrom1 == cfromc) {
/*        CFROMC is an inf.  Multiply by a correctly signed zero for */
/*        finite CTOC, or a NaN if CTOC is infinite. */
	mul = ctoc / cfromc;
	done = TRUE_;
	cto1 = ctoc;
    } else {
	cto1 = ctoc / bignum;
	if (cto1 == ctoc) {
/*           CTOC is either 0 or an inf.  In both cases, CTOC itself */
/*           serves as the correct multiplication factor. */
	    mul = ctoc;
	    done = TRUE_;
	    cfromc = 1.f;
	} else if (dabs(cfrom1) > dabs(ctoc) && ctoc != 0.f) {
	    mul = smlnum;
	    done = FALSE_;
	    cfromc = cfrom1;
	} else if (dabs(cto1) > dabs(cfromc)) {
	    mul = bignum;
	    done = FALSE_;
	    ctoc = cto1;
	} else {
	    mul = ctoc / cfromc;
	    done = TRUE_;
	}
    }

    if (itype == 0) {

/*        Full matrix */

	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
	    i__2 = *m;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		a[i__ + j * a_dim1] *= mul;
/* L20: */
	    }
/* L30: */
	}

    } else if (itype == 1) {

/*        Lower triangular matrix */

	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
	    i__2 = *m;
	    for (i__ = j; i__ <= i__2; ++i__) {
		a[i__ + j * a_dim1] *= mul;
/* L40: */
	    }
/* L50: */
	}

    } else if (itype == 2) {

/*        Upper triangular matrix */

	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
	    i__2 = min(j,*m);
	    for (i__ = 1; i__ <= i__2; ++i__) {
		a[i__ + j * a_dim1] *= mul;
/* L60: */
	    }
/* L70: */
	}

    } else if (itype == 3) {

/*        Upper Hessenberg matrix */

	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
/* Computing MIN */
	    i__3 = j + 1;
	    i__2 = min(i__3,*m);
	    for (i__ = 1; i__ <= i__2; ++i__) {
		a[i__ + j * a_dim1] *= mul;
/* L80: */
	    }
/* L90: */
	}

    } else if (itype == 4) {

/*        Lower half of a symmetric band matrix */

	k3 = *kl + 1;
	k4 = *n + 1;
	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
/* Computing MIN */
	    i__3 = k3, i__4 = k4 - j;
	    i__2 = min(i__3,i__4);
	    for (i__ = 1; i__ <= i__2; ++i__) {
		a[i__ + j * a_dim1] *= mul;
/* L100: */
	    }
/* L110: */
	}

    } else if (itype == 5) {

/*        Upper half of a symmetric band matrix */

	k1 = *ku + 2;
	k3 = *ku + 1;
	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
/* Computing MAX */
	    i__2 = k1 - j;
	    i__3 = k3;
	    for (i__ = max(i__2,1); i__ <= i__3; ++i__) {
		a[i__ + j * a_dim1] *= mul;
/* L120: */
	    }
/* L130: */
	}

    } else if (itype == 6) {

/*        Band matrix */

	k1 = *kl + *ku + 2;
	k2 = *kl + 1;
	k3 = (*kl << 1) + *ku + 1;
	k4 = *kl + *ku + 1 + *m;
	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
/* Computing MAX */
	    i__3 = k1 - j;
/* Computing MIN */
	    i__4 = k3, i__5 = k4 - j;
	    i__2 = min(i__4,i__5);
	    for (i__ = max(i__3,k2); i__ <= i__2; ++i__) {
		a[i__ + j * a_dim1] *= mul;
/* L140: */
	    }
/* L150: */
	}

    }

    if (! done) {
	goto L10;
    }

    return 0;

/*     End of SLASCL */

} /* slascl_ */