## help please

## help please

(OP)

Hi,,

I have afortran program for calculating density and when I execute it gives me zero and error.

program density

implicit none

integer :: r,IDm,n,m,i,j

real :: xm,ym,zm,p,p0,k,pi,s,ri,rj,l

real, dimension(1000) :: x,y,z,ID

p0=0.17

k=0.0

L=4.33

pi=3.1415927

do n=1,3000

open(unit=5,file='/home/toshiba/Desktop/urqmd-3.3p2/format1.dat')

read(5,*) l,l,l,l

do m=1,400

read(5,*) xm,ym,zm,IDm

if(xm==400) exit

r=m

x(r)=xm

y(r)=ym

z(r)=zm

ID(r)=IDm

write(*,*) xm, ym, zm, IDm

end do

do i=1,r-1

x(i)=xm

y(i)=ym

z(i)=zm

do j=i+1,r

x(j)=x(i+1)

y(j)=y(i+1)

z(j)=z(i+1)

s=ri-rj

s=sqrt((x(i)-x(j))**2 + (y(i)-y(j))**2 + (z(i)-z(j))**2)

K=K+s

end do

end do

p=(1/394)*(1/(2*pi*L)**1.5)*exp(-(K)**2/(2*L))*p0

write(*,*) p/p0

end do

end program density

can any one help me..

I have afortran program for calculating density and when I execute it gives me zero and error.

program density

implicit none

integer :: r,IDm,n,m,i,j

real :: xm,ym,zm,p,p0,k,pi,s,ri,rj,l

real, dimension(1000) :: x,y,z,ID

p0=0.17

k=0.0

L=4.33

pi=3.1415927

do n=1,3000

open(unit=5,file='/home/toshiba/Desktop/urqmd-3.3p2/format1.dat')

read(5,*) l,l,l,l

do m=1,400

read(5,*) xm,ym,zm,IDm

if(xm==400) exit

r=m

x(r)=xm

y(r)=ym

z(r)=zm

ID(r)=IDm

write(*,*) xm, ym, zm, IDm

end do

do i=1,r-1

x(i)=xm

y(i)=ym

z(i)=zm

do j=i+1,r

x(j)=x(i+1)

y(j)=y(i+1)

z(j)=z(i+1)

s=ri-rj

s=sqrt((x(i)-x(j))**2 + (y(i)-y(j))**2 + (z(i)-z(j))**2)

K=K+s

end do

end do

p=(1/394)*(1/(2*pi*L)**1.5)*exp(-(K)**2/(2*L))*p0

write(*,*) p/p0

end do

end program density

can any one help me..

## RE: help please

In computer programs, if you type 2 is a 2 and not a 2.0; without decimal point a number is an integer. When dividing two integers you only get the quotient...6/3=2, 7/3=2 ...and when the denominator is greater, you get the quotient of zero: 1/2=0, 1/394=0

If you do not desire integral division, you need to make sure one of the operands is a REAL number, i.e., has a decimal point or is a variable declared accordingly.