I need to work on Fortran90 code on my Macbook Pro, which was written on Microsoft Developer Tools years ago. As a free option, I have installed gfortran on my Macbook to be able to compile it. The original code includes & continuation character for the long lines but I am not able to use it. Without & character, everything works fine. What might be the problem? Do I need to activate something to be able to use & character?
For example, I think something like this should work:
x = 1
y = 2
z = x+
&y
end
But instead, I am having this error. It might be end of line error. How can I solve it?
3:72: Error: Syntax error in expression at (1)
4:9: Error: Invalid character in name at (1)
In free-form Fortran, the line continuation character (&) at the end of the line to be continued. Your code should read:
program test
x = 1
y = 2
z = x+ &
y
end program
This is stated in the Fortran Standard (here: 2008, but applicable as well for Fortran 90), Cl. 3.3.2.4 "Free form statement continuation":
1 The character “&” is used to indicate that the statement is continued on the next line that is not a comment line. [...]
2 If a noncharacter context is to be continued, an “&” shall be the last nonblank character on the line, or the last nonblank character before an “!”. [...]
Related
I want to display the progress of a calculation done with a DO-loop, on the console screen. I can print out the progress variable to the terminal like this:
PROGRAM TextOverWrite_WithLoop
IMPLICIT NONE
INTEGER :: Number, Maximum = 10
DO Number = 1, MAXIMUM
WRITE(*, 100, ADVANCE='NO') REAL(Number)/REAL(Maximum)*100
100 FORMAT(TL10, F10.2)
! Calcultations on Number
END DO
END PROGRAM TextOverWrite_WithLoop
The output of the above code on the console screen is:
10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00
90.00 100.00
All on the same line, wrapped only by the console window.
The ADVANCE='No' argument and the TL10 (tab left so many spaces) edit descriptor works well to overwrite text on the same line, e.g. the output of the following code:
WRITE(*, 100, ADVANCE='NO') 100, 500
100 FORMAT(I3, 1X, TL4, I3)
Is:
500
Instead of:
100 500
Because of the TL4 edit descriptor.
From these two instances one can conclude that the WRITE statement cannot overwrite what has been written by another WRITE statement or by a previous execution of the same WRITE satement (as in a DO-loop).
Can this be overcome somehow?
I am using the FTN95 compiler on Windows 7 RC1. (The setup program of the G95 compiler bluescreens Windows 7 RC1, even thought it works fine on Vista.)
I know about the question Supressing line breaks in Fortran 95 write statements, but it does not work for me, because the answer to that question means new ouput is added to the previous output on the same line; instead of new output overwriting the previous output.
Thanks in advance.
The following should be portable across systems by use of ACHAR(13) to encode the carriage return.
character*1 creturn
! CODE::
creturn = achar(13) ! generate carriage return
! other code ...
WRITE( * , 101 , ADVANCE='NO' ) creturn , i , npoint
101 FORMAT( a , 'Point number : ',i7,' out of a total of ',i7)
There is no solution to this question within the scope of the Fortran standards. However, if your compiler understand backslash in Fortran strings (GNU Fortran does if you use the option -fbackslash), you can write
write (*,"(A)",advance="no") "foo"
call sleep(1)
write (*,"(A)",advance="no") "\b\b\bbar"
call sleep(1)
write (*,"(A)",advance="no") "\b\b\bgee"
call sleep(1)
write (*,*)
end
This uses the backslash character (\b) to erase previously written characters on that line.
NB: if your compiler does not understand advance="no", you can use related non-standard tricks, such as using the $ specifier in the format string.
The following worked perfectly using g95 fortran:
NF = NF + 1
IF(MOD(NF,5).EQ.0) WRITE(6,42,ADVANCE='NO') NF, ' PDFs'//CHAR(13)
42 FORMAT(I6,A)
gave:
5 PDFs
leaving the cursor at the #1 position on the same line. On the next update,
the 5 turned into a 10. ASCII 13 (decimal) is a carriage return.
OPEN(6,CARRIAGECONTROL ='FORTRAN')
DO I=1,5
WRITE(6,'(1H+" ",I)') I
ENDDO
Here's what I'm trying to run:
if (z.le.zstart) then
if (y.ge.((6.95*wg_y2)/5)).and.(y.le.((12.55*wg_y2)/5)) then
indexmedia=nd
end if
end if
For context,
zstart is an arbitrary line of constant y.
wg_y2 = 5e-6
And for some reason it doesn't like the (y.ge.((6.95*wg_y2)/5)) bit, as the (1) was placed at the end of that bit.
I had a suspicion that it doesn't like anything that isn't an integer in the if statement but I changed 6.95 to 7 and 12.55 to 13 and it still didn't like it. Perhaps it needs to end up resolving to an integer?
I need these parameters to end up to
6.95 < y < 12.55 though.
Is there a workaround for this?
When compiling the code (not nice as I didn't declare the variables!, but that isn't the problem here so I abstain from it to keep it a bit small):
program tst
if (z.le.zstart) then
if (y.ge.((6.95*wg_y2)/5)).and.(y.le.((12.55*wg_y2)/5)) then
indexmedia=nd
end if
end if
end
one gets the error:
aa.f90:3:29:
if (y.ge.((6.95*wg_y2)/5)).and.(y.le.((12.55*wg_y2)/5)) then
1
Error: Cannot assign to a named constant at (1)
aa.f90:6:3:
end if
1
Error: Expecting END PROGRAM statement at (1)
This is due to a missing pair of round brackets in the line:
if (y.ge.((6.95*wg_y2)/5)).and.(y.le.((12.55*wg_y2)/5)) then
which should read
if ((y.ge.((6.95*wg_y2)/5)).and.(y.le.((12.55*wg_y2)/5))) then
I wrote the following two lines in fortran
C23456789
REAL H3 = 0
H3=H*H*H
and I received the following errors from gdb :
ljmd.f:186.5:
REAL H3 = 0
1
Error: Non-numeric character in statement label at (1)
ljmd.f:187.5:
H3=H*H*H
1
Error: Non-numeric character in statement label at (1)
ljmd.f:187.6:
H3=H*H*H
1
What is the proper way to create and use new variables in the middle of someone else's fortran program? C23456789 is my label of the current column used in the program.
This is in any random Fortran tutorial. I expect you have the fixed source form. Then any statement must start at column 7 or farther.
Also,
REAL H3 = 0
isn't legal in free form source Fortran and does a completely different thing in fixed form (see #francesalus' comment). And in your case there is no reason to initialize the variable at all. You can just do
REAL H3
H3 = H**3
If you happen to need the initialization somewhere else, you either must use
real :: a = 0
(requires Fotran 90), or
REAL A
DATA A/0/
(in Fortran77). Beware, both version make the variable SAVE which you may know as static from other languages.
The last point, you cannot introduce variables anywhere "in the middle of program", the declaration of variables have their place at the beginning of each compilation unit (program, function, subroutine,...).
Not sure if this is an appropriate question, but just recently I've noticed that when I run a C++ program in the terminal when it exits it has a % sign after the last output. For example a hello world program says "hello world%". What is this and how do I get rid of it? I'm on OS X, shell is zsh. Unless I am crazy it has never done this until now.
There are two possibilities that I can think of off hand:
1) You aren't printing a carriage return, so the % prompt appears at the end of the printed text instead of on the next line. (Is the % your standard prompt in the shell?)
2) You are printing past the end of a buffer and getting a random character as a result.
I'd guess #1 based on what you describe, but both could cause the behavior.
I'm currently porting an application from Fortran to C and need to output some variables to compare results. I'm very new to Fortran, and although i understand the code and have now ported several thousand lines, I'm a noob at writing Fortran code myself.
This code:
write(6,'(A,I3,A,E12.8,A,E12.8,A,E12.8,A,E12.8,A,E12.8)') 'iHyd:',
& ih,'; dzdr: ',dzdr,'; tauray:', tauRay,'; zRay: ',
& zray,'; ampRay: ',realpart(aray),'+j*',
& imagpart(aray),'; qRay: ',qray,'; width :',w
Compiles fine, but when run, the program exits with:
At line 296 of file calcpr.for (unit = 6, file = 'stdout')
Fortran runtime error: Expected INTEGER for item 15 in formatted transfer, got REAL
(A,I3,A,E12.8,A,E12.8,A,E12.8,A,E12.8,A,E12.8)
^
q0: 1432.3944878270595
nArrayR: 501 nArrayZ: 201
iHyd: 1; dzdr: ************; tauray:************; zRay: ************; ampRay: NaN+j* NaN
; qRay:
Besides being really ugly, it doesn't make much sense to me, as ìh is declared as integer*8 and not as real.
So how can i solve this?
I'm counting 6 character&variable specifications in the format statement, but you're printing 8 of them.
edit:
a nicer use of the format statement would be '(A,I3,7(A,E12.8))'
Fortran "recycles" the format if there are more things to be printed than specified in the format statement. If a write statement gives results you don't understand, to diagonose the problem it may be helpful to remove the things printed one at a time until the error goes away.
It says "item 15", which I would take to be down near the end of your list, not ih at the beginning. It's clear that both "w" and "qray" are being printed as REAL; is either one of them an INTEGER? You may need to change the format specifier then.