EVSL  1.1.0 EigenValues Slicing Library
landosG.c File Reference

Function to use Lanczos method for approximating DOS for the generalized eigenvalue problem. More...

`#include <float.h>`
`#include <math.h>`
`#include <stdio.h>`
`#include <stdlib.h>`
`#include "blaslapack.h"`
`#include "def.h"`
`#include "evsl.h"`
`#include "internal_proto.h"`
`#include "string.h"`
`#include "struct.h"`

Go to the source code of this file.

## Functions

int LanDosG (const int nvec, const int msteps, int npts, double *xdos, double *ydos, double *neig, const double *const intv)

## Detailed Description

Function to use Lanczos method for approximating DOS for the generalized eigenvalue problem.

Definition in file landosG.c.

## Function Documentation

 int LanDosG ( const int nvec, const int msteps, int npts, double * xdos, double * ydos, double * neig, const double *const intv )

Computes the density of states (DOS, or spectral density) using Lanczos algorithm for the generalized eigenvalue problem.

Parameters
 [in] nvec number of sample vectors used [in] msteps number of Lanczos steps [in] npts number of sample points used for the DOS curve [in] *intv Stores the the intervals of interest intv[0:1] = [a b] = interval where DOS is to be computed intv[2:3] = [lambda_min, lambda_max] \ [out] *xdos Length-npts long vector, x-coordinate points for plotting the DOS. Must be preallocated before calling LanDos [out] *ydos Length-npts long vector, y-coordinate points for plotting the DOS. Must be preallocated before calling LanDos [out] neig estimated number of eigenvalues
Note
This works for both the standard and generalized eigenvalue problems.

## landos.c/LanDos is only for the standard eigenvalue problem.

Definition at line 43 of file landosG.c.

Referenced by main().

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