CalcSpectrumByFullDiag.c File Reference

Functions to perform spectrum calculations with the full-diagonalization method. More...

#include <complex.h>
#include "global.h"
#include <time.h>
#include "struct.h"
#include "lapack_diag.h"
#include "makeHam.h"
#include "CalcTime.h"

Go to the source code of this file.

Functions
void	zcopy_ (int *n, double complex *x, int *incx, double complex *y, int *incy)
void	zdotc_ (double complex *xy, int *n, double complex *x, int *incx, double complex *y, int *incy)
int	CalcSpectrumByFullDiag (struct EDMainCalStruct *X, int Nomega, double complex *dcSpectrum, double complex *dcomega)
	Compute the Green function with the Lehmann representation and FD \[ G(z) = \sum_n \frac{|\langle n|c|0\rangle|^2}{z - E_n} \] . More...

Detailed Description

Functions to perform spectrum calculations with the full-diagonalization method.

Definition in file CalcSpectrumByFullDiag.c.

Function Documentation

CalcSpectrumByFullDiag()

int CalcSpectrumByFullDiag	(	struct EDMainCalStruct *	X,
		int	Nomega,
		double complex *	dcSpectrum,
		double complex *	dcomega
	)

Compute the Green function with the Lehmann representation and FD

\[ G(z) = \sum_n \frac{|\langle n|c|0\rangle|^2}{z - E_n} \]

.

Author

Mitsuaki Kawamura (The University of Tokyo)

• Generate fully stored Hamiltonian. Because v0 & v1 are overwritten, copy v0 into vg.

  
  
  
  

• v0 becomes eigenvalues in lapack_diag(), and L_vec becomes eigenvectors

  
  
  

• Compute \(|\langle n|c|0\rangle|^2\) for all \(n\) and store them into v1, where \(c|0\rangle\) is vg.

  
  

• Compute spectrum

  \[ \sum_n \frac{|\langle n|c|0\rangle|^2}{z - E_n} \]

Parameters

[in,out]	X
[in]	Nomega	Number of frequencies
[out]	dcSpectrum	[Nomega] Spectrum
[in]	dcomega	[Nomega] Frequency

Definition at line 37 of file CalcSpectrumByFullDiag.c.

References EDMainCalStruct::Bind, BindStruct::Check, CheckList::idim_max, L_vec, lapack_diag(), makeHam(), StartTimer(), StopTimer(), TRUE, v0, v1, vg, X, and zcopy_().

Referenced by CalcSpectrum().

{
  int idim, jdim, iomega;
  int idim_max_int;
  int incr=1;
  idim_max_int = (int)X->Bind.Check.idim_max;
  zcopy_(&idim_max_int, &v0[1], &incr, &vg[0], &incr);

  StartTimer(6301);
  makeHam(&(X->Bind));
  StopTimer(6301);
  StartTimer(6302);
  lapack_diag(&(X->Bind));
  StopTimer(6302);
  StartTimer(6303);

  for (idim = 0; idim < idim_max_int; idim++) {
    v1[idim] = 0.0;
    for (jdim = 0; jdim < idim_max_int; jdim++) v1[idim] += conj(vg[jdim]) * L_vec[idim][jdim];
    //zdotc_(&v1[idim], &idim_max_int, &vg[0], &incr, &L_vec[idim][0], &incr);
    v1[idim] = conj(v1[idim]) * v1[idim];
  }/*for (idim = 0; idim < idim_max_int; idim++)*/
  StopTimer(6303);
  StartTimer(6304);
  for (iomega = 0; iomega < Nomega; iomega++) {
    dcSpectrum[iomega] = 0.0;
    for (idim = 0; idim < idim_max_int; idim++) {
      dcSpectrum[iomega] += v1[idim] / (dcomega[iomega] - v0[idim]);
    }/*for (idim = 0; idim < idim_max_int; idim++)*/
  }/*for (iomega = 0; iomega < Nomega; iomega++)*/
  StopTimer(6304);
  return TRUE;
}/*CalcSpectrumByFullDiag*/

zcopy_()

void zcopy_	(	int *	n,
		double complex *	x,
		int *	incx,
		double complex *	y,
		int *	incy
	)

Referenced by CalcSpectrumByFullDiag().

zdotc_()

void zdotc_	(	double complex *	xy,
		int *	n,
		double complex *	x,
		int *	incx,
		double complex *	y,
		int *	incy
	)