You are using "write" statement to write "pt" expression into a file. The difference between the first and second statements of your code because you used two other format in FORTRAN. For more detail, you can refer to below link "http://www.cs.mtu.edu/~shene/COURSES/cs201/NOTES/chap05/format.html"

Did you have the same problem?

Your first WRITE statement give a line that looks like this:

pt=

No values of variable pt are written.

Use your second WRITE statement with this FORMAT statement:

80 format (1x,"pt=",6(1pe11.3e3))

and it will write a line (or multiple lines, if there are more than 6 elements in variable array pt) that looks like this:

 pt= 1.234E+001-2.345E+187 3.456E-005 etc.

If you don't expect to get exponents of more than two digits, you can use:

80 format (1x,"pt=",6(1pe11.4))

and it will write a line that looks like this:

pt= 1.2345E+01-2.3452E+87 3.4563E-05 etc.