forums.silverfrost.com

[KL]

Dear Paul,

this is certaily a programmer's error and of less importance.

Nevertheless, I send it because such a misuse should
lead to an error message:

I understood, that the elemental function MAX needs at least
2 arguments. Since MAX is elemental, they can be scalars or arrays.

In the following test program, MAX is used only with one array argument x. This is of course a programmer error. The statement

Max_x = Max (x)

leads to a compiler error with the message

"Array expressions, such as the array 'X', cannot be on the right hand side of scalar assignments".

However, the statement

Max_x = Max (x (1:3))

gives the wrong value 1.

Would it not be better, to give an error message whenever MAX is called with just one argument, whether it is a scalar, an array or an array section?

I have run the program with FTN95 Version 4.7 and a bat file:


del comp.lis
del *.obj
del *.exe

ftn95 MAX_Test.f95 /Checkmate /underflow /Link >> comp.lis

sdbg MAX_Test.exe

The program is:
Winapp

Program MAX_Test

Implicit None
Real , Dimension ( 3 ) :: x
Real :: Max_x

x (1) = +9.
x (2) = 0.
x (3) = +1.

! The next statement is wrong. It is detected by the compiler:

! "Array expressions, such as the array 'X', cannot be on the right hand side
! of scalar assignments"


! Max_x = Max (x)

! The next statement is also wrong, but it is not detected:

Max_x = Max (x (1:3)) ! gives the wrong answer
Write (*,*) Max_x


End MAX_Test

[PaulLaidler]

Klaus

Thank for this. I will add it to the list of things to investigate.

[PaulLaidler]

Following your recommendation, this has now been fixed and improved.
The change will appear in version 5.1.

[KL]

Paul, thank you very much

Klaus