problem using formatted Fortran `write(6,*)` output - fortran

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.

Related

moving the file position back by one single character to over-write it, in fortran [duplicate]

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

How to determine file size in Fortran 77

I have a Fortran program that needs to read ASCII files, however the list of files sometimes includes a file of size 0. The program then crashes when trying to read this file. I have not find any way so far that will allow me to flag such a file.
I have following READ statement in my code
read(10,220,END=320,ERR=195)parm(1:)
although I expect code to go to statement 195, or to statement 320, without crashing, it crashes
this is where the code crashes when the file size is zero, with the following messages
...
fmt: end of file
apparent state: unit 10 named junko.con
last format: (A)
lately reading sequential formatted external IO
I tried using the INQUIRE statement
inquire (unit=10,SIZE=nsize), but the program would not compile
the OPEN statement did not give any error when opening the zero size file, and the values of IOSTAT was the same, irrespective of the file size
As Ian noted, any modern Fortran compiler should have INQUIRE. A simple test of
program foo
integer sz
inquire(file='tmp.dat',size=sz)
print *, sz
end program foo
with an empty tmp.dat file sets sz=0.

Fortran is reading beyond endfile record

I'm trying to read some data from a file, and the endfile record detection is important to stop reading. However, depending of the array dimensions of the array used to read data, I cannot detect properly the endfile record and my Fortran program stops.
The program is below:
!integer, dimension(3) :: x ! line 1.1
!integer, dimension(3,10) :: x ! line 1.2
integer, dimension(10,3) :: ! line 1.3
integer :: status,i=1
character(len=100) :: error
open( 30, file='data.dat', status='old' )
do
print *,i
!read( 30, *, iostat=status, iomsg=error ) x ! line 2.1
!read( 30, *, iostat=status, iomsg=error ) x(:,i) ! line 2.2
read( 30, *, iostat=status, iomsg=error ) x(i,:) ! line 2.3
if ( status < 0 ) then print *,'EOF'
print *,'total of ',i-1,' lines read.'
exit
else if ( status > 0 ) then
print *,'error cod: ',status
print *,'error message: ', error
stop
else if ( status == 0 ) then
print *,'reading ok.'
i = i + 1
end if
end do
With 'data.dat' file been:
10 20 30
30 40 50
When lines 1.3 and 2.3 are uncommented the mentioned error appears:
error cod: 5008
error message: Read past ENDFILE record
However, using lines 1.1 and 2.1, or 1.2 and 2.2, the program works, detecting endfile record.
So, I would like some help on understanding why I cannot use lines 1.3 and 2.3 to read properly this file, since I'm giving the correct number of array elements for read command.
I'm using gfortran compiler, version 6.3.0.
EDIT: simpler example
the following produces a 5008 "Read past ENDFILE record" error:
implicit none
integer x(2,2),s
open(20,file='noexist')
read(20,*,iostat=s)x
write(*,*)s
end
if we make x a scalar or a one-d array ( any size ) we get the expected -1 EOF flag. It doesn't matter if the file actually doesn't exist or is empty. If the file contains some, but not enough, data its hard to make sense of which return value you might get.
I am not sure if I am expressing myself correctly but it has to do with the way fortran is reading and storing 2d-arrays. When you are using this notation: x(:,i), the column i is virtually expanded in-line and the items are read using this one line of code. In the other case where x(i,:) is used, the row i is read as if you called read multiple times.
You may use implied loops if you want to stick with a specific shape and size. For example you could use something like that:read( 30, *, iostat=status, iomsg=error ) (x(i,j), j=1,3)
In any case you should check that your data are stored properly (as expected at least) in variable x.
Please note this is only a guess. Remember that Fortran stores arrays in column major order. When gfortran compiles read() x(:,i), the 3 memory locations are next to each other so in the executable, it produces a single call to the operating system to read in 3 values from the file.
Now when read() x(i,:) is compiled, the three data elements x(i,1), x(i,2) and x(i,3) are not in contiguous memory. So I am guessing the executable actually has 3 read calls to the operating system. The first one would trap the EOF but the 2nd one gives you the read past end of file error.
UPDATE: I have confirmed that this does not occur with Intel's ifort. gfortran seems to have had a similar problem before: Bad IOSTAT values when readings NAMELISTs past EOF. Whether this is a bug or not is debatable. The code certainly looks like it should trap an EOF.

Fortran's warning on a program for evaluating elliptic integrals

On internet, I found this program that demonstrate Evaluating elliptic integrals of first and second kinds (complete)
implicit none
real*8 e,e1,e2,xk
integer i, n
e=1.d-7
print *,' K K(K) E(K) STEPS '
print *,'------------------------------------------'
xk=0.d0
do i = 1, 20
call CElliptic(e,xk,e1,e2,n)
write(*,50) xk,e1,e2,n
xk = xk + 0.05d0
end do
print *,'1.00 INFINITY 1.0000000 0'
stop
50 format(' ',f4.2,' ',f9.7,' ',f9.7,' ',i2)
end
Complete elliptic integral of the first and second kind. The input parameter is xk, which should be between 0 and 1. Technique uses Gauss' formula for the arithmogeometrical mean. e is a measure of the convergence accuracy. The returned values are e1, the elliptic integral of the first kind, and e2, the elliptic integral of the second kind.
Subroutine CElliptic(e,xk,e1,e2,n)
! Label: et
real*8 e,xk,e1,e2,pi
real*8 A(0:99), B(0:99)
integer j,m,n
pi = 4.d0*datan(1.d0)
A(0)=1.d0+xk ; B(0)=1.d0-xk
n=0
if (xk < 0.d0) return
if (xk > 1.d0) return
if (e <= 0.d0) return
et n = n + 1
! Generate improved values
A(n)=(A(n-1)+B(n-1))/2.d0
B(n)=dsqrt(A(n-1)*B(n-1))
if (dabs(A(n)-B(n)) > e) goto et
e1=pi/2.d0/A(n)
e2=2.d0
m=1
do j = 1, n
e2=e2-m*(A(j)*A(j)-B(j)*B(j))
m=m*2
end do
e2 = e2*e1/2.d0
return
end
I have compiled it but I have received the following errors:
gfortran -Wall -c "gauss.f" (nel direttorio: /home/pierluigi/Scrivania)
gauss.f:53.9:
50 format(' ',f4.2,' ',f9.7,' ',f9.7,' ',i2)
1
Error: Invalid character in name at (1)
gauss.f:83.72:
if (dabs(A(n)-B(n)) > e) goto et
1
Warning: Deleted feature: Assigned GOTO statement at (1)
gauss.f:83.35:
if (dabs(A(n)-B(n)) > e) goto et
1
Error: ASSIGNED GOTO statement at (1) requires an INTEGER variable
gauss.f:48.18:
write(*,50) xk,e1,e2,n
1
Error: FORMAT label 50 at (1) not defined
Compilation failed.
Any suggestions please?
EDIT
I have read all your answers and thanks to you I managed to compile the program. I also have another curiosity and I do not know whether to write another question. In the meantime I modify this question. In my program, xk is increased by 0.05. Now I will that the program to read data from a file containing: the minimum value of xk; the maximum value of xk; the number of intervals. I thought:
open (10,file='data/test')
read (10,*) xkmi, xkma
read (10,*) nk
close (10)
lkmi = dlog(xkmi)
lkma = dlog(xkma)
ldk = (lkma-lkmi)/dfloat(nk-1)
In addition, the program must be modified in such a way that the result is written to another file. How can I change the rest of the program? Thank you very much.
Your source code file extension is f which, I think (check the documentation), tells gfortran that the file contains fixed source form. Until Fortran 90 Fortran was still written as if onto punched cards and the location of various bits and pieces of a line is confined to certain columns. A statement label, such as 50 in the first of the error messages, had to be in columns 1 - 6. Two solutions:
Make sure the label is in (some of) those columns. Or, better
Move to free source form, perhaps by changing the file extension to f90, perhaps by using a compilation option (check your documentation).
The error raised by the goto et phrase is, as your compiler has told you, an example of a deleted feature, in which the goto jumps to a statement whose label is provided at run-time, ie the value of et. Either tell your compiler (check ...) to conform to an old standard, or modernise your source.
Fix those errors and, I suspect, the other error messages will disappear. They are probably raised as a consequence of the compiler not correctly parsing the source after the errors.
Because the file has type ".f" gfortan is interpreting it as fixed-source layout. Trying compiling with the free-form layout by using compiler option -ffree-form and see if that works. This probably explains the error about the "invalid character". That statement not being recognized explains the "format not defined error". The "computed goto" is obsolete but valid Fortran. You can ignore that warning. If you wish, later you can modernize the code. For the remaining error, for the "assigned goto", declare "et" as an integer.
I would just do this
10 n = n + 1
! Generate improved values
A(n)=(A(n-1)+B(n-1))/2.d0
B(n)=dsqrt(A(n-1)*B(n-1))
if (dabs(A(n)-B(n)) > e) goto 10
and possibly compile as free form source as others have shown. The label et seems weird and non-standard, possibly a rare vendor extension.
You could also change the lines above to a do-loop with an exit statement (Fortran 90).
(The program compiled for me after the change).
I tested the subroutine and compared with matlab and it was not the same. It is very similar to the algorithm used in Abramowitz's book. Here is the one I wrote that works well, just for comparing.
subroutine CElliptic(m,K,E)
implicit none
real*8 m,alpha,E,K,A,B,C,A_p,B_p,C_0,pi,suma
integer j,N
N=100
alpha=asin(sqrt(m))
pi = 4.d0*datan(1.d0)
A_p=1.0
B_p=cos(alpha)
C_0=sin(alpha)
suma=0.0
do j=1,N
A=(A_p+B_p)/2.0d0
B=dsqrt(A_p*B_p)
C=(A_p-B_p)/2.0d0
suma=suma+2**(j)*C**2
A_p=A
B_p=B
end do
K=pi/(2*A)
E=(1-1.d0/2.d0*(C_0**2+suma))*K
end Subroutine CElliptic
best regards
Ed.

Strange output and branch warning when compiling

I compile a fortran 77 code using gfortran and get the following error:
10 open (23,file=outfile,status='old',access='append',err=10)
1
Warning: Branch at (1) may result in an infinite loop
This happens several times.
One of the output files looks like the following:
^L6a10È <90> ) &<9b>LÓLÓLÕ<91><90> <90> <90> È <8e><9b>LÓLÓLÕ<93>2
!MERCURY ¢¤õ/!ô<8a><8a><90> ÿ<90> ÿ<90> ÿÌÖÏ©ü}M<91>
"VENUS «}>±{©±<8b><90> ÿ<90> ÿ<90> ÿʺ93¿<8d>d<91>
However, it should just look like a table of text.
Any ideas?
Your line of code
10 open (23,file=outfile,status='old',access='append',err=10)
specifies that the open statement should transfer control to itself (label 10) in case an error is encountered, so any error could trigger an infinite loop. It also suppresses the output of error messages. If you want to just check for an error status, I would suggest using the iostat and/or iomsg (Fortran 2003) arguments:
open (23, file=outfile, status='old', access='append', iostat=ios, iomsg=str)
Here ios is an integer that will be zero if no errors occur and nonzero otherwise, and str is a character variable that will record the corresponding error message.
The err= argument in your open statement specifies a statement label to branch to should the open fail for some reason. Your code specifies a branch to the line labelled 10 which happens to be the line containing the open statement. This is probably not a good idea; a better idea would be to branch to a line which deals gracefully with an error from the open statement.
The warning from gfortran is spot on.
As to the apparent garbage in your output file, without sight of the code you use to write the garbage (or what you think are pearls perhaps) it's very difficult to diagnose and fix that problem.