source/unres/src_MD-M/intcor.f

   1 C
   2 C------------------------------------------------------------------------------
   3 C
   4       double precision function alpha(i1,i2,i3)
   5 c
   6 c  Calculates the planar angle between atoms (i1), (i2), and (i3).
   7 c
   8       implicit real*8 (a-h,o-z)
   9       include 'DIMENSIONS'
  10       include 'COMMON.GEO'
  11       include 'COMMON.CHAIN'
  12       x12=c(1,i1)-c(1,i2)
  13       x23=c(1,i3)-c(1,i2)
  14       y12=c(2,i1)-c(2,i2)
  15       y23=c(2,i3)-c(2,i2)
  16       z12=c(3,i1)-c(3,i2)
  17       z23=c(3,i3)-c(3,i2)
  18       vnorm=dsqrt(x12*x12+y12*y12+z12*z12)
  19       wnorm=dsqrt(x23*x23+y23*y23+z23*z23)
  20       if ((vnorm.eq.0.0).or.(wnorm.eq.0.0)) then
  21       scalar=1.0
  22       else
  23       scalar=(x12*x23+y12*y23+z12*z23)/(vnorm*wnorm)
  24       endif
  25       alpha=arcos(scalar)
  26       return
  27       end
  28 C
  29 C------------------------------------------------------------------------------
  30 C
  31       double precision function beta(i1,i2,i3,i4)
  32 c
  33 c  Calculates the dihedral angle between atoms (i1), (i2), (i3) and (i4)
  34 c
  35       implicit real*8 (a-h,o-z)
  36       include 'DIMENSIONS'
  37       include 'COMMON.GEO'
  38       include 'COMMON.CHAIN'
  39       x12=c(1,i1)-c(1,i2)
  40       x23=c(1,i3)-c(1,i2)
  41       x34=c(1,i4)-c(1,i3)
  42       y12=c(2,i1)-c(2,i2)
  43       y23=c(2,i3)-c(2,i2)
  44       y34=c(2,i4)-c(2,i3)
  45       z12=c(3,i1)-c(3,i2)
  46       z23=c(3,i3)-c(3,i2)
  47       z34=c(3,i4)-c(3,i3)
  48 cd    print '(2i3,3f10.5)',i1,i2,x12,y12,z12
  49 cd    print '(2i3,3f10.5)',i2,i3,x23,y23,z23
  50 cd    print '(2i3,3f10.5)',i3,i4,x34,y34,z34
  51       wx=-y23*z34+y34*z23
  52       wy=x23*z34-z23*x34
  53       wz=-x23*y34+y23*x34
  54       wnorm=dsqrt(wx*wx+wy*wy+wz*wz)
  55       vx=y12*z23-z12*y23
  56       vy=-x12*z23+z12*x23
  57       vz=x12*y23-y12*x23
  58       vnorm=dsqrt(vx*vx+vy*vy+vz*vz)
  59       if (vnorm.gt.1.0D-13 .and. wnorm.gt.1.0D-13) then
  60       scalar=(vx*wx+vy*wy+vz*wz)/(vnorm*wnorm)
  61       if (dabs(scalar).gt.1.0D0)
  62      &scalar=0.99999999999999D0*scalar/dabs(scalar)
  63       angle=dacos(scalar)
  64 cd    print '(2i4,10f7.3)',i2,i3,vx,vy,vz,wx,wy,wz,vnorm,wnorm,
  65 cd   &scalar,angle
  66       else
  67       angle=pi
  68       endif
  69 c     if (angle.le.0.0D0) angle=pi+angle
  70       tx=vy*wz-vz*wy
  71       ty=-vx*wz+vz*wx
  72       tz=vx*wy-vy*wx
  73       scalar=tx*x23+ty*y23+tz*z23
  74       if (scalar.lt.0.0D0) angle=-angle
  75       beta=angle
  76       return
  77       end
  78 C
  79 C------------------------------------------------------------------------------
  80 C
  81       function dist(i1,i2)
  82 c
  83 c  Calculates the distance between atoms (i1) and (i2).
  84 c
  85       implicit real*8 (a-h,o-z)
  86       include 'DIMENSIONS'
  87       include 'COMMON.GEO'
  88       include 'COMMON.CHAIN'
  89       x12=c(1,i1)-c(1,i2)
  90       y12=c(2,i1)-c(2,i2)
  91       z12=c(3,i1)-c(3,i2)
  92       dist=dsqrt(x12*x12+y12*y12+z12*z12)
  93       return
  94       end
  95 C