1 | include(dom.inc)
   2 |       SUBROUTINE calculatearea(nb_nodes, nodelist, area)
   3 | 
   4 | !       ================================================================!
   5 | !                                                                       !
   6 | !       calculatearea.F : Calculates the surface of any kind of face    !
   7 | !                                                                       !
   8 | !       in              : The number of nodes of the face 'nb_nodes'    !
   9 | !                         The id list of the nodes                      !
  10 | !       out             : The face's surface value 'area'               !
  11 | !                                                                       !
  12 | !       author          : J. AMAYA (avril 2007)                         !
  13 | !                                                                       !
  14 | !       ================================================================!
  15 | 
  16 |         USE datas
  17 |         IMPLICIT NONE
  18 | 
  19 | !       IN
  20 |         DOM_INT           :: nb_nodes
  21 |         DOM_INT, DIMENSION(nb_nodes) :: nodelist
  22 | 
  23 | !       OUT
  24 |         DOM_REAL  :: area
  25 | 
  26 | !       LOCAL
  27 |         DOM_REAL  :: s, a, b, c, a1, a2
  28 |         DOM_REAL  :: x1, y1, z1, x2, y2, z2, x3, y3, z3
  29 |         DOM_INT           :: ierr
  30 | 
  31 | !       -------------------!
  32 | !       For the edge in 2D !
  33 | !       -------------------!
  34 |         IF (nb_nodes.eq.2) THEN
  35 |           x1 = node_list(1, nodelist(1))
  36 |           y1 = node_list(2, nodelist(1))
  37 | 
  38 |           x2 = node_list(1, nodelist(2))
  39 |           y2 = node_list(2, nodelist(2))
  40 | 
  41 |           a = x2 - x1
  42 |           b = y2 - y1
  43 | 
  44 |           area = SQRT( a*a + b*b )
  45 | !       -------------------!
  46 | !       For the triangle : !
  47 | !       -------------------!
  48 |         ELSE IF (nb_nodes.eq.3) THEN
  49 | 
  50 |           x1 = node_list(1, nodelist(1))
  51 |           y1 = node_list(2, nodelist(1))
  52 |           z1 = node_list(3, nodelist(1))
  53 | 
  54 |           x2 = node_list(1, nodelist(2))
  55 |           y2 = node_list(2, nodelist(2))
  56 |           z2 = node_list(3, nodelist(2))
  57 | 
  58 |           x3 = node_list(1, nodelist(3))
  59 |           y3 = node_list(2, nodelist(3))
  60 |           z3 = node_list(3, nodelist(3))
  61 | 
  62 |           a=SQRT((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)+(z2-z1)*(z2-z1))
  63 |           b=SQRT((x3-x2)*(x3-x2)+(y3-y2)*(y3-y2)+(z3-z2)*(z3-z2))
  64 |           c=SQRT((x1-x3)*(x1-x3)+(y1-y3)*(y1-y3)+(z1-z3)*(z1-z3))
  65 | 
  66 |           s = (a + b + c) / 2
  67 |           area = SQRT(s*(s-a)*(s-b)*(s-c))
  68 | 
  69 | !       ----------------!
  70 | !       For the square: !
  71 | !       ----------------!
  72 |         ELSE
  73 |           
  74 |           x1 = node_list(1, nodelist(1))
  75 |           y1 = node_list(2, nodelist(1))
  76 |           z1 = node_list(3, nodelist(1))
  77 | 
  78 |           x2 = node_list(1, nodelist(2))
  79 |           y2 = node_list(2, nodelist(2))
  80 |           z2 = node_list(3, nodelist(2))
  81 | 
  82 |           x3 = node_list(1, nodelist(3))
  83 |           y3 = node_list(2, nodelist(3))
  84 |           z3 = node_list(3, nodelist(3))
  85 | 
  86 |           a=SQRT((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)+(z2-z1)*(z2-z1))
  87 |           b=SQRT((x3-x2)*(x3-x2)+(y3-y2)*(y3-y2)+(z3-z2)*(z3-z2))
  88 |           c=SQRT((x1-x3)*(x1-x3)+(y1-y3)*(y1-y3)+(z1-z3)*(z1-z3))
  89 | 
  90 |           s = (a + b + c) / 2
  91 |           a1 = SQRT(s*(s-a)*(s-b)*(s-c))
  92 | 
  93 |           x2 = node_list(1, nodelist(4))
  94 |           y2 = node_list(2, nodelist(4))
  95 |           z2 = node_list(3, nodelist(4))
  96 | 
  97 |           a=SQRT((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)+(z2-z1)*(z2-z1))
  98 |           b=SQRT((x3-x2)*(x3-x2)+(y3-y2)*(y3-y2)+(z3-z2)*(z3-z2))
  99 | 
 100 |           s = (a + b + c) / 2
 101 |           a2 = SQRT(s*(s-a)*(s-b)*(s-c))
 102 | 
 103 |           area = a1 + a2
 104 | 
 105 |         ENDIF
 106 | 
 107 |       END SUBROUTINE calculatearea