org.netlib.lapack
Class SLAGTS

java.lang.Object
  extended by org.netlib.lapack.SLAGTS

public class SLAGTS
extends java.lang.Object

SLAGTS is a simplified interface to the JLAPACK routine slagts.
This interface converts Java-style 2D row-major arrays into
the 1D column-major linearized arrays expected by the lower
level JLAPACK routines.  Using this interface also allows you
to omit offset and leading dimension arguments.  However, because
of these conversions, these routines will be slower than the low
level ones.  Following is the description from the original Fortran
source.  Contact seymour@cs.utk.edu with any questions.

* .. * * Purpose * ======= * * SLAGTS may be used to solve one of the systems of equations * * (T - lambda*I)*x = y or (T - lambda*I)'*x = y, * * where T is an n by n tridiagonal matrix, for x, following the * factorization of (T - lambda*I) as * * (T - lambda*I) = P*L*U , * * by routine SLAGTF. The choice of equation to be solved is * controlled by the argument JOB, and in each case there is an option * to perturb zero or very small diagonal elements of U, this option * being intended for use in applications such as inverse iteration. * * Arguments * ========= * * JOB (input) INTEGER * Specifies the job to be performed by SLAGTS as follows: * = 1: The equations (T - lambda*I)x = y are to be solved, * but diagonal elements of U are not to be perturbed. * = -1: The equations (T - lambda*I)x = y are to be solved * and, if overflow would otherwise occur, the diagonal * elements of U are to be perturbed. See argument TOL * below. * = 2: The equations (T - lambda*I)'x = y are to be solved, * but diagonal elements of U are not to be perturbed. * = -2: The equations (T - lambda*I)'x = y are to be solved * and, if overflow would otherwise occur, the diagonal * elements of U are to be perturbed. See argument TOL * below. * * N (input) INTEGER * The order of the matrix T. * * A (input) REAL array, dimension (N) * On entry, A must contain the diagonal elements of U as * returned from SLAGTF. * * B (input) REAL array, dimension (N-1) * On entry, B must contain the first super-diagonal elements of * U as returned from SLAGTF. * * C (input) REAL array, dimension (N-1) * On entry, C must contain the sub-diagonal elements of L as * returned from SLAGTF. * * D (input) REAL array, dimension (N-2) * On entry, D must contain the second super-diagonal elements * of U as returned from SLAGTF. * * IN (input) INTEGER array, dimension (N) * On entry, IN must contain details of the matrix P as returned * from SLAGTF. * * Y (input/output) REAL array, dimension (N) * On entry, the right hand side vector y. * On exit, Y is overwritten by the solution vector x. * * TOL (input/output) REAL * On entry, with JOB .lt. 0, TOL should be the minimum * perturbation to be made to very small diagonal elements of U. * TOL should normally be chosen as about eps*norm(U), where eps * is the relative machine precision, but if TOL is supplied as * non-positive, then it is reset to eps*max( abs( u(i,j) ) ). * If JOB .gt. 0 then TOL is not referenced. * * On exit, TOL is changed as described above, only if TOL is * non-positive on entry. Otherwise TOL is unchanged. * * INFO (output) INTEGER * = 0 : successful exit * .lt. 0: if INFO = -i, the i-th argument had an illegal value * .gt. 0: overflow would occur when computing the INFO(th) * element of the solution vector x. This can only occur * when JOB is supplied as positive and either means * that a diagonal element of U is very small, or that * the elements of the right-hand side vector y are very * large. * * ===================================================================== * * .. Parameters ..


Constructor Summary
SLAGTS()
           
 
Method Summary
static void SLAGTS(int job, int n, float[] a, float[] b, float[] c, float[] d, int[] in, float[] y, floatW tol, intW info)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SLAGTS

public SLAGTS()
Method Detail

SLAGTS

public static void SLAGTS(int job,
                          int n,
                          float[] a,
                          float[] b,
                          float[] c,
                          float[] d,
                          int[] in,
                          float[] y,
                          floatW tol,
                          intW info)