X-Git-Url: http://mmka.chem.univ.gda.pl/gitweb/?a=blobdiff_plain;f=source%2Funres%2Fsrc_MD-M-newcorr%2Frefsys.f;fp=source%2Funres%2Fsrc_MD-M-newcorr%2Frefsys.f;h=8c58a829d238d92bba7e63c85d5958936f42f2a7;hb=d101c97dea752458d76055fdbae49c26fff03c1f;hp=0000000000000000000000000000000000000000;hpb=325eda160c9ad2982501e091ca40606a29043712;p=unres.git

diff --git a/source/unres/src_MD-M-newcorr/refsys.f b/source/unres/src_MD-M-newcorr/refsys.f
new file mode 100644
index 0000000..8c58a82
--- /dev/null
+++ b/source/unres/src_MD-M-newcorr/refsys.f
@@ -0,0 +1,68 @@
+      subroutine refsys(i2,i3,i4,e1,e2,e3,fail)
+c This subroutine calculates unit vectors of a local reference system
+c defined by atoms (i2), (i3), and (i4). The x axis is the axis from
+c atom (i3) to atom (i2), and the xy plane is the plane defined by atoms
+c (i2), (i3), and (i4). z axis is directed according to the sign of the
+c vector product (i3)-(i2) and (i3)-(i4). Sets fail to .true. if atoms
+c (i2) and (i3) or (i3) and (i4) coincide or atoms (i2), (i3), and (i4)
+c form a linear fragment. Returns vectors e1, e2, and e3.
+      implicit real*8 (a-h,o-z)
+      include 'DIMENSIONS'
+      logical fail
+      double precision e1(3),e2(3),e3(3)
+      double precision u(3),z(3)
+      include 'COMMON.IOUNITS'
+      include 'COMMON.CHAIN'
+      double precision coinc/1.0D-13/,align /1.0D-13/
+      fail=.false.
+      s1=0.0
+      s2=0.0
+      do 1 i=1,3
+      zi=c(i,i2)-c(i,i3)
+      ui=c(i,i4)-c(i,i3)
+      s1=s1+zi*zi
+      s2=s2+ui*ui
+      z(i)=zi
+    1 u(i)=ui
+      s1=sqrt(s1)
+      s2=sqrt(s2)
+      if (s1.gt.coinc) goto 2
+      write (iout,1000) i2,i3,i1
+      fail=.true.
+c     do 3 i=1,3
+c   3 c(i,i1)=0.0D0
+      return
+    2 if (s2.gt.coinc) goto 4
+      write(iout,1000) i3,i4,i1
+      fail=.true.
+      do 5 i=1,3
+    5 c(i,i1)=0.0D0
+      return
+    4 s1=1.0/s1
+      s2=1.0/s2
+      v1=z(2)*u(3)-z(3)*u(2)
+      v2=z(3)*u(1)-z(1)*u(3)
+      v3=z(1)*u(2)-z(2)*u(1)
+      anorm=dsqrt(v1*v1+v2*v2+v3*v3)
+      if (anorm.gt.align) goto 6
+      write (iout,1010) i2,i3,i4,i1
+      fail=.true.
+c     do 7 i=1,3
+c   7 c(i,i1)=0.0D0
+      return
+    6 anorm=1.0D0/anorm
+      e3(1)=v1*anorm
+      e3(2)=v2*anorm
+      e3(3)=v3*anorm
+      e1(1)=z(1)*s1
+      e1(2)=z(2)*s1
+      e1(3)=z(3)*s1
+      e2(1)=e1(3)*e3(2)-e1(2)*e3(3)
+      e2(2)=e1(1)*e3(3)-e1(3)*e3(1)
+      e2(3)=e1(2)*e3(1)-e1(1)*e3(2)
+ 1000 format (/1x,' * * * Error - atoms',i4,' and',i4,' coincide.',
+     1 'coordinates of atom',i4,' are set to zero.')
+ 1010 format (/1x,' * * * Error - atoms',2(i4,2h, ),i4,' form a linear',
+     1 ' fragment. coordinates of atom',i4,' are set to zero.')
+      return
+      end