finite element method problem 1

[yehia1984]

i am a begginner in fortran and am trying to write a program that calulates the distance between two points, in order to identify duplicate co ordinates.

there are a list of co ordinate points and for each of these co ordinate points is a corresponding label, i.e. co-ordinat point 1 is node 1, co ordiante point 2 is node 2 etc (e.g. (0,0) is node 1, (0,3) is node 2, (0,6) is node 3 etc...)

Once the distance has been calculated the prgram then runs an IF statement with the criteria that if the distance is less that 10E-6 that it would flag this result, in an IFLAG vector of the nodal points.

does any on know how to do this? i would really appreciate it.

thanks

ps am willing to descirbe the problem in more detail if you need it.

 

[Panzer55]

To calculate the distance between two points, you have to use the formula: dist=SQRT((x(j)-x(i))**2+(y(j)-y(i))**2). Let me propose you a process that is much faster and would guarantee you don't have duplicate coordinates:

Do I=1,NumbOfCoord
IM1=I+1
Do J=IM1,NumbOfCoord
If(ABS(x(i)-x(j)).GT.0.10D-5)Cycle
If(ABS(y(i)-y(j)).GT.0.10D-5)Cycle
Write(*,1000)I,J
1000 Format("Points",I4," and",I4," have the",
*" same coordinates")
End Do
End Do