Fortran Error # 6366: The shapes of the array expressions do not conform

Question

I encountered this error message while compiling one of my Fortran codes. I found a few similar posts regarding the same error, but none of the situations in those posts apply to my case. I would appreciate any answer or help offered here. Thanks in advance!

(The code is really long, so I only cut out those sentences that are relevant.)

===================================================

DIMENSION A(20), COORDS(3)
REAL  B, C, X, Y, Z

B = 1.0

X = COORDS(1)
Y = COORDS(2)
Z = COORDS(3)

DO I = 1,3
  A(I) = COORDS(I)
END DO

C = SQRT ( X**2.0 + Y**2.0 ) + B

===================================================

The error message points to the last line: error #6366: The shapes of the array expressions do not conform. [C]

If I comment out + B, then no error occurs.

I just don't get it. The elements of the array COORDS are passed on to scalar variables X, Y, Z. How come they and B (or C) are not conformable?

I know there must be something I don't quite understand about Fortran array. Please point out my mistake if you catch any.

Thanks a lot!

Justin

Solution

Is there a dimension statement elsewhere in the code for any of these variables? The error message seems to point to C; that commenting out +B eliminates the error seems to more solidly point to B.

This is why I like to have all characteristics of a variable declared on a single line. e.g.,

real, dimension (20) :: a

instead of:

dimension A(20)
real A

Comments

[Steve Lionel]

In more detail - the compiler believes that B is an array but C, X and Y are not. Adding +B to the expression turns the entire expression into an array, but if C is not also an array of the same shape, that's an error. In cases such as this, it is more helpful to provide a small but complete example that shows the problem, rather than an excerpt or paraphrase, as these often leave out critical details.