!
!     CalculiX - A 3-dimensional finite element program
!              Copyright (C) 1998 Guido Dhondt
!
!     This program is free software; you can redistribute it and/or
!     modify it under the terms of the GNU General Public License as
!     published by the Free Software Foundation(version 2);
!     
!
!     This program is distributed in the hope that it will be useful,
!     but WITHOUT ANY WARRANTY; without even the implied warranty of 
!     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
!     GNU General Public License for more details.
!
!     You should have received a copy of the GNU General Public License
!     along with this program; if not, write to the Free Software
!     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
! 
      This file describes the variables used in CalculiX and their meaning

REARRANGEMENT OF THE ORDER IN THE INPUT DECK

      ifreeinp:       next blank line in field inp

      ipoinp(1,i):    index of the first column in field inp
                      containing information on a block of lines in 
                      the input deck corresponding to fundamental key i;
                      a fundamental key is a key for which the order
                      in the input file matters
                      (the fundamental keys are listed in file keystart.f)
      ipoinp(2,i):    index of the last column in field inp 
                      containing information on a block of lines in
                      the input deck corresopnding to fundamental key i;

      inp:            a column i in field inp (i.e. inp(1..3,i))
                      corresponds to a uninterupted block of lines
                      assigned to one and the same fundamental key
                      in the input deck. inp(1,i) is its first line
                      in the input deck, inp(2,i) its last line and
                      inp(3,i) the next column in inp corresponding 
                      to the same fundamental key; it takes the value
                      0 if none other exists.

MATERIAL DESCRIPTION
 
      nmat:           # materials
      
      matname(i):     name of material i
 
      nelcon(1,i):     # (hyper)elastic constants for material i
                      (negative kode for nonlinear elastic constants)
      nelcon(2,i):     # temperature data points for the elastic constants
                      of material i
      elcon(0,j,i):   temperature at (hyper)elastic temperature point j of
                      material i
      elcon(k,j,i):   (hyper)elastic constant k at elastic temperature point j
                      of material i
 
      nrhcon(i):      # temperature data points for the density of 
                      material i
      rhcon(0,j,i):   temperature at density temperature point j of
                      material i
      rhcon(1,j,i):   density at the density temperature point j of
                      material i
      
      nshcon(i):      # temperature data points for the specific heat of 
                      material i
      shcon(0,j,i):   temperature at specific heat temperature point j of
                      material i
      shcon(1,j,i):   specific heat at the specific heat temperature point j of
                      material i
      
      nalcon(1,i):    # of expansion constants for material i
      nalcon(2,i):    # of temperature data points for the expansion
                      coefficients of material i
      alcon(0,j,i):   temperature at expansion temperature point j
                      of material i
      alcon(k,j,i):   expansion coefficient k at expansion temperature
                      point j of material i
 
      ncocon(1,i):    # of conductivity constants for material i
      ncocon(2,i):    # of temperature data points for the conductivity
                      coefficients of material i
      cocon(0,j,i):   temperature at conductivity temperature point j
                      of material i
      cocon(k,j,i):   conductivity coefficient k at conductivity temperature
                      point j of material i
 
      orname(i):      name of orientation i
      orab(1..6,i):   coordinates of points a and b defining the new
                      orientation
      norien:         # orientations

      isotropic hardening:

      nplicon(0,i):   # temperature data points for the isotropic hardening
                      curve of material i
      nplicon(j,i):   # of stress - plastic strain data points at temperature
                      j for material i
      plicon(0,j,i):  temperature data point j of material i
      plicon(2*k-1,j,i): stress corresponding to stress-plastic strain data
                         point
                         k at temperature data point j of material i
      plicon(2*k,j,i):   plastic strain corresponding to stress-plastic strain
                         data point k at temperature data point j of material i

      kinematic hardening:

      nplkcon(0,i):      # temperature data points for the kinematic hardening
                         curve of material i
      nplkcon(j,i):      # of stress - plastic strain data points at 
                         temperature j for material i
      plkcon(0,j,i):     temperature data point j of material i
      plkcon(2*k-1,j,i): stress corresponding to stress-plastic strain data 
                         point  k at temperature data point j of material i
      plkcon(2*k,j,i):   plastic strain corresponding to stress-plastic strain
                         data point
                         k at temperature data point j of material i

      kode=-1:           Arrudy-Boyce
           -2:           Mooney-Rivlin
	   -3:           Neo-Hooke
	   -4:           Ogden (N=1)
	   -5:           Ogden (N=2)
	   -6:           Ogden (N=3)
	   -7:           Polynomial (N=1)
	   -8:           Polynomial (N=2)
	   -9:           Polynomial (N=3)
	   -10:          Reduced Polynomial (N=1)
	   -11:          Reduced Polynomial (N=2)
	   -12:          Reduced Polynomial (N=3)
	   -13:          Van der Waals (not implemented yet)
	   -14:          Yeoh
	   -15:          Hyperfoam (N=1)
	   -16:          Hyperfoam (N=2)
	   -17:          Hyperfoam (N=3)
	   -50:          deformation plasticity
	   -51:          incremental plasticity (no viscosity)
	   -52:          viscoplasticity
        < -100:          user material routine with -kode-100 user
                         defined constants with keyword *USER MATERIAL


PROCEDURE DESCRIPTION

      iperturb:       0: linear
                      1: second order theory
                      2: nonlinear geometric
                      3: nonlinear elastic material (and nonlinear geometric)

      nmethod:        1: static (linear or nonlinear)
                      2: frequency(linear)
	              3: buckling (linear)
                      4: dynamic (linear or nonlinear)

GEOMETRY DESCRIPTION
   
      nk:             highest node number
      co(i,j):        coordinate i of node j
      intr(1,j):      transformation number applicable in node j
      intr(2,j):      a SPC in a node j in which a transformation
                      applies corresponds to a MPC. intr(2,j) contains
                      the number of a new node generated for the 
                      inhomogeneous part of the MPC
  

TOPOLOGY DESCRIPTION

      ne:             highest element number
      mint_:          max # of integration points per element (max over all 
                      elements)
      kon(i):         field containing the connectivity lists of the 
                      elements in successive order

      For element i:

      ipkon(i):       (location in kon of the first node in the element
                      connectivity list of element i)-1
      lakon(i):       element label
      ielorien(i):    orientation number
      ielmat(i):      material number

SHELL (2-D) AND BEAM (1-D) VARIABLES (INCLUDING PLANE STRAIN, PLANE
 STRESS AND AXISYMMETRIC ELEMENTS) 

      iponor(2,i):    two pointers for entry i of kon. The first
                      pointer points to the location in xnor preceding
                      the normals of entry i, the second points to the
                      location in knor of the newly generated
                      dependent nodes of entry i.
      xnor(i):        field containing the normals in nodes on the
                      elements they belong to
      knor(i):        field containing the extra nodes needed to
                      expand the shell and beam elements to volume
                      elements
      thickn(2,i):    thicknesses (one for shells, two for beams) in
                      node i
      thicke(2,i):    thicknesses (one for shells, two for beams) in
                      element nodes. The entries correspond to the
                      nodal entries in field kon
      offset(2,i):    offsets (one for shells, two for beams) in
                      element i
      iponoel(i):     pointer for node i into field inoel, which
                      stores the 1-D and 2-D elements belonging to the
                      node.
      inoel(3,i):     field containing an element number, a local node
                      number within this element and a pointer to
                      another entry (or zero if there is no
                      other).
      inoelfree:      next free field in inoel
      rig(i):         character*1 field indicating whether node i is a
                      rigid node ('R') or not (' '). In a rigid node
                      or knot all expansion nodes except the ones not
                      in the midface of plane stress, plane strain and
                      axisymmetric elements are connected with a rigid
                      body MPC 

AMPLITUDES

      nam:            # amplitude definitions

      amta(1,j):      time of (time,amplitude) pair j
      amta(2,j):      amplitude of (time,amplitude) pair j
      namtot:         total # of (time,amplitude) pairs

      For amplitude i:

      amname(i):      name of the amplitude
      namta(1,i):     location of first (time,amplitude) pair in
                      field amta
      namta(2,i):     location of last (time,amplitude) pair in 
                      field amta

TRANSFORMS

      ntrans          # transform definitions
      trab(1..6,i)    coordinates of two points defining the transform
      trab(7,i)       =1 for rectangular transformations
                      =2 for cylindrical transformations
  
SINGLE POINT CONSTRAINTS

      nboun           # SPC's

      For SPC (single point constraint) i:
      
      nodeboun(i):    SPC node
      ndirboun(i):    SPC direction
      typeboun(i):    SPC type (SPCs can contain the nonhomogeneous
                      part of MPCs):
                      B=prescribed boundary condition
                      M=midplane
                      P=planempc
                      R=rigidbody
                      S=straigthmpc
                      U=usermpc
      xboun(i):       magnitude of constraint at end of a step
      xbounold(i):    magnitude of constraint at beginning of a step
      xbounact(i):    magnitude of constraint at the end of the present
                      increment
      xbounini(i):    magnitude of constraint at the start of the
                      present increment
      iamboun(i):     amplitude number
      ikboun(i):      ordered array of the DOFs corresponding to the
                      SPC's (DOF=3*(nodeboun(i)-1)+ndirboun(i))
      ilboun(i):      original SPC number for ikboun(i) 

MULTIPLE POINT CONSTRAINTS

      ipompc(i):      starting location in nodempc and coefmpc of MPC i
      
      nodempc(1,ipompc(i)),nodempc(1,nodempc(3,ipompc(i))),
      nodempc(1,nodempc(3,nodempc(3,nodempc(3,ipompc(i)))),...
      until nodempc(3,nodempc(3,......))))))=0:
                      nodes belonging to MPC i

      nodempc(2,ipompc(i)),nodempc(2,nodempc(3,ipompc(i))),
      nodempc(2,nodempc(3,nodempc(3,nodempc(3,ipompc(i)))),...
      until nodempc(3,nodempc(3,......))))))=0:
                      directions belonging to MPC i

      xbounmpc(ipompc(i)),xbounmpc(nodempc(3,ipompc(i))),
      xbounmpc(nodempc(3,nodempc(3,nodempc(3,ipompc(i)))),...
      until nodempc(3,nodempc(3,......))))))=0:
                      coefficients belonging to MPC i
      ikmpc (i):      ordered array of the dependent DOFs
                      corresponding to the MPC's
		      DOF=3*(nodempc(1,ipompc(i))-1)+nodempc(2,ipompc(i))
      ilmpc (i):      original SPC number for ikmpc(i) 

      icascade:       0: MPC's did not change since the last iteration
                      1: MPC's changed since last iteration:
                         dependency check in cascade.c necessary
                      2: at least one nonlinear MPC had DOFs in common
                         with a linear MPC or another nonlinear MPC.
                         dependency check is necessary in each iteration
 
POINT LOADS

      nforc:          # of point loads

      For point load i:

      nodeforc(i):    node in which force is applied
      ndirforc(i):    direction of force
      xforc(i):       magnitude of force at end of a step
      xforcold(i):    magnitude of force at start of a step
      xforcact(i):    actual magnitude
      iamforc(i):     amplitude number
      ikforc(i):      ordered array of the DOFs corresponding to the
                      point loads (DOF=3*(nodeboun(i)-1)+ndirboun(i)) 
      ilforc(i):      original SPC number for ikforc(i) 

DISTRIBUTED LOADS

      nload:          # of facial distributed loads

      For distributed load i:

      nelemload(1,i): element to which distributed load is applied
      nelemload(2,i): node for the environment temperature (only for
                      heat transfer analyses)
      sideload(i):    load label; indicated element side to which load
                      is applied
      xload(1,i):     magnitude of load at end of a step or, for heat
                      transfer analyses, the convection (*FILM) or the
                      radiation coefficient (*RADIATE)
      xload(2,i):     the environment temperature (only for heat
                      transfer analyses
      xloadold(1..2,i):magnitude of load at start of a step
      xloadact(1..2,i):actual magnitude of load
      iamload(1,i):   amplitude number for xload(1,i)
      iamload(2,i):   amplitude number for xload(2,i)

MASS FLOW RATE

      nflow:          # of mass flow rates

      For mass flow rate i:

      nodeflow(1,i):  node from which the mass flows
      nodeflow(2,i):  node to which the mass flows
      xflow(i):       magnitude of the mass flow rate
      xflowold(i):    magnitude of the mass flow rate at start of a step
      xflowact(i):    actual magnitude of the mass flow rate
      iamflow(i):     amplitude number for xflow(i)

TEMPERATURE LOADS

      t0(i):          initial temperature in node i at the start of the
                      calculation
      t1(i):          temperature at the end of a step in node i
      t1old(i):       temperature at the start of a step in node i
      t1act(i):       actual temperature in node i
      iamt1(i):       amplitude number

CENTRIFUGAL LOADING

      om:             square of the rotational speed at the end of a step
      omold:          square of the rotational speed at the start of a step
      omact:          actual value of the square of the rotational speed
      iamom:          amplitude number
      p1(i):          coordinate i of a first point on the rotation axis
      p2(i):          coordinate i of a second point on the rotation axis

GRAVITY LOADING

      bodyf(i):       coordinate i of the body force at the end of a step
      bodyfold(i):    coordinate i of the body force at the start of a step
      bodyfact(i):    coordinate i of the actual body force
      iambodyf:       amplitude number

STRESS AND STRAIN FIELDS

      eei(i,j,k):     in general:
                      Lagrange strain component i in integration point j
                      of element k (linear strain in linear elastic 
                      calculations)

                      for elements with *DEFORMATION PLASTICITY property:
                      Eulerian strain component i in integration point j
                      of element k (linear strain in linear elastic 
                      calculations)

      eeiini(i,j,k):  Lagrange strain component i in integration point
                      of element k at the start of an increment

      een(i,j):       Lagrange strain component i in node j (mean over all
                      adjacent elements linear strain in linear elastic
                      calculations)

      stx(i,j,k):     Cauchy or PK2
                      stress component i in integration point j
                      of element k at the end of an iteration
                      (linear stress in linear elastic calculations) 

      sti(i,j,k):     PK2 stress component i in integration point j
                      of element k at the start of an iteration
                      (linear stress in linear elastic calculations) 

      stiini(i,j,k):  PK2 stress component i in integration point j
                      of element k at the start of an increment 

      stn(i,j):       Cauchy stress component i in node j (mean over all 
                      adjacent elements; "linear" stress in linear elastic
                      calculations)

THERMAL ANALYSIS

      ithermal:       0: no temperatures involved in the calculation
                      1: stress analysis with given temperature field
                      2: thermal analysis (no displacements)
                      3: coupled thermal-mechanical analysis:
                         temperatures and displacements are solved for
                         simultaneously

      v(0,j):         temperature of node j at the end of
                      an iteration (for ithermal > 1)
      vold(0,j):      temperature of node j  at the start
                      of an iteration (for ithermal > 1)
      vini(0,j):      temperature of node j at the start
                      of an increment (for ithermal > 1)

      fn(0,j):        actual temperature at node j (for ithermal > 1)

      qfx(i,j,k):     heat flux component i in integration point j
                      of element k at the end of an iteration

      qfn(i,j):       heat flux component i in node j (mean over all 
                      adjacent elements)


DISPLACEMENTS AND SPATIAL/TIME DERIVATIVES

      v(i,j):         displacement of node j in direction i at the end of
                      an iteration
      vold(i,j):      displacement of node j in direction i at the start
                      of an iteration
      vini(i,j):      displacement of node j in direction i at the start
                      of an increment

      ve(i,j):        velocity of node j in direction i at the end of
                      an iteration
      veold(i,j):     velocity of node j in direction i at the start
                      of an iteration
      veini(i,j):     velocity of node j in direction i at the start
                      of an increment

      accold(i,j):    acceleration of node j in direction i at the start
                      of an iteration
      accini(i,j):    acceleration of node j in direction i at the start
                      of an increment

      vkl(i,j):       (i,j) component of the displacement gradient tensor
                      at the end of an iteration

      xkl(i,j):       (i,j) component of the deformation gradient tensor
                      at the end of an iteration

      xikl(i,j):      (i,j) component of the deformation gradient tensor
                      at the start of an increment

      ckl(i,j):       (i,j) component of the inverse of the deformation
                      gradient tensor

LINEAR EQUATION SYSTEM

      ad(i):          element i on diagonal of stiffness matrix
      au(i):          element i in upper triangle of stiffness matrix
      adb(i):         element i on diagonal of mass matrix, or, for
                      buckling, of the incremental stiffness matrix
                      (only nonzero elements are stored)
      aub(i):         element i in upper triangle of mass matrix, or, for
                      buckling, of the incremental stiffness matrix
                      (only nonzero elements are stored)
      neq[0]:         # of mechanical equations
      neq[1]:         sum of mechanical and thermal equations
      nzl:            number of the column such that all columns with
                      a higher column number do not contain any
                      (projected) nonzero off-diagonal terms (<= neq[1])
      nzs:            sum of projected nonzero off-diagonal terms
      nactdof(i,j):   actual degree of freedom (in the system of equations)
                      of DOF i of node j (0 if not active)

INTERNAL AND EXTERNAL FORCES

      fext(i):        external mechanical forces in DOF i (due to point
                      loads and distributed loads, including centrifugal and
                      gravity loads, but excluding temperature loading and
                      displacement loading)

      fextini(i):     external mechanical forces in DOF i (due to point
                      loads and distributed loads, including centrifugal and
                      gravity loads, but excluding temperature loading and
                      displacement loading) at the end of the last increment

      finc(i):        external mechanical forces in DOF i augmented by 
                      contributions due to temperature loading and prescribed
                      displacements; used in linear calculations only

      f(i):           actual internal forces in DOF i due to: 
                      actual displacements in the independent nodes;
                      prescribed displacements at the end of the increment
                      in the dependent nodes;
                      temperatures at the end of the increment in all nodes 

      fini(i):        internal forces in DOF i at the end of the last
                      increment

      b(i):           right hand side of the equation system: difference
                      between fext and f in nonlinear calcultions; for linear
                      calculations, b=finc.

      fn(i,j):        actual force at node j in direction i

INCREMENT PARAMETERS

      tinc:           user given increment size (can be modified by the 
                      program if the parameter DIRECT is not activated)
      tper:           user given step size

      dtheta:         normalized (by tper) increment size
      theta:          normalized (by tper) size of all previous increments (not
                      including the present increment)
      reltime:        theta+dtheta

      dtime:          real time increment size
      time:           real time size of all previous increments INCLUDING
                      the present increment

DIRECT INTEGRATION DYNAMICS

      alpha,bet,gam:  parameter in the alpha-method of Hilber, Hughes and 
                      Taylor
      iexpl:          =0: implicit dynamics
                      =1: explicit dynamics 

FREQUENCY CALCULATIONS

      mei(0)          number of requested eigenvalues
      mei(1)          number of Lanczos vectors
      mei(2)          maximum number of iterations
      fei(0)          tolerance (accuracy)
      fei(1)          lower value of requested frequency range
      fei(2)          upper value of requested frequency range