SUBROUTINE EXLDA ( EXCHEN )
Argument Definitions (+ indicates altered content)
REAL*8            +EXCHEN
Description
  Copyright (C) 1978 Charlotte Froese Fisher 
  Copyright (C) 2012 Jacek Kobus 
 
 
exlda calculates LDA contribution to exchange energy 
 
FIXME: the factors due to the angular part of orbitals are still 
missing
Source file:exlda.f
Parameter Variables Used
INTEGER            MAXNO              (MAXNO = 29999)
INTEGER            MAXORB             (MAXORB = 20)
REAL*8             CONST13            (CONST13 = 1.D0/3.D0)
REAL*8             CONST43            (CONST43 = 4.D0/3.D0)
REAL*8             CONST53            (CONST53 = 5.D0/3.D0)
REAL*8             CONST98            (CONST98 = 9.D0/8.D0)
Local Variables (+ indicates altered content)
INTEGER           +J,         +JJ,        +JP,        +K
INTEGER           +M
REAL*8            +D,         +FDFTEN,    +RHOT,      +Y243
Referenced Common Block Variables (+ indicates altered content)
CONST              REAL*8             PII,       THREE
MCOMMBLOCK         REAL*8             P(MAXORB,MAXNO)
MCOMMBLOCK         REAL*8             R(MAXNO)
PARAM              INTEGER            NO,        NWF
PARAM              REAL*8             H1
PARAM1             REAL*8             D0,        D1
PARAM1             REAL*8             D2
REL                REAL*8            +VDFT(MAXNO)
REL                REAL*8             XALPHA
STATE              REAL*8             QC(MAXORB,40)