TABLE OF CONTENTS

::pwtk::pwi::celldm3

SYNOPSIS

proc ::pwtk::pwi::celldm3 {} {

PURPOSE

Get the value of celldm(3) or C in units of alat, depending on which is specified. If neither is specified 0.0 is returned.

RETURN VALUE

Either the value of celldm(3) or the value of C converted to units of alat or 0.0 if neither of celldm(3) and C is defined.

SOURCE

    set C       [::pwtk::pwi::cC]
    set celldm3 [::pwtk::input::namelistGetVarValue SYSTEM celldm(3)]

    if { $C != "" && $celldm3 != "" } {
        pwtk::error "both C and celldm(3) are specified, specify only one of them !!!" 1
    }

    if { $C != "" } {
        set alat [::pwtk::pwi::alat]
        if { $alat == 0.0 } {
            ::pwtk::warning "from ::pwtk::pwi::celldm3: neither celldm(1) nor A are specified"
            set alat 1.0
        }
            
        set celldm3 [expr $::pwtk::angs2bohr * $C / $alat]
    }    
    if { $celldm3 == "" } {
        set celldm3 0.0
    }
    
    return $celldm3
}