Fortran [Fortran 90/95] Error: function has no IMPLICIT type

AI Thread Summary
The discussion centers on a compilation error in a Fortran program related to the function 'BMatScal', which is not recognized due to an implicit type issue. The user initially encounters an error stating that 'BMatScal' has no implicit type, despite having defined it within a module. The solution involves addressing the 'PRIVATE' declaration in the module, which restricts access to the function. It is suggested to either remove the 'PRIVATE' statement or explicitly declare 'BMatScal' as 'PUBLIC' to ensure it can be accessed in the program. The conversation highlights the importance of managing module visibility in Fortran, allowing for internal constants and functions to remain private while selectively exposing necessary components.
ted_kingdom
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Hi!
I get an error when trying to compile my program:
Code:
test8.f95:26.8:

 BMat = BMatScal(InverseJacobian, ShapeFuncDeriv)
        1
Error: Function 'bmatscal' at (1) has no IMPLICIT type

I don't know why it complains because I specified type of the function in its definition (please see code below):
Code:
MODULE q12
	INTEGER, PARAMETER,PUBLIC::NDIM=2,NNODES=4, NDIR = 2, NSHR = 1
END MODULE q12

MODULE BMatricesScalar
	IMPLICIT NONE
	PRIVATE
	CONTAINS
! BMatScal function provides B-matrix for scalar-valued variable (e.g. temperature)
		FUNCTION BMatScal(JacobiInv, ShapeFuncDeriv)
			REAL, INTENT(IN) :: JacobiInv(:,:), ShapeFuncDeriv(:,:)
			REAL :: BMatScal(SIZE(JacobiInv,1),SIZE(ShapeFuncDeriv,2))
			
			BMatScal = MATMUL(JacobiInv, ShapeFuncDeriv)
		END FUNCTION BMatScal
END MODULE BMatricesScalar

PROGRAM q2
	USE q12
	USE BMatricesScalar
	IMPLICIT NONE
	REAL:: InverseJacobian(2,2) = RESHAPE((/1,1,1,1/),(/2,2/)),&
			 ShapeFuncDeriv(2,4) = RESHAPE((/0.0,-0.5,0.0,0.0,0.5,0.0,-0.5,0.5/),(/2,4/)),&
			 BMat(NDIR,NNODES)
			 
	BMat = BMatScal(InverseJacobian, ShapeFuncDeriv)
	PRINT*, BMat(1,:)
	PRINT*, BMat(2,:)
END PROGRAM q2

What am I missing? Thanks in advance.
 
Last edited:
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Have you added 'use BMatriceScalar' in your program?
 
Ah I see you have. My mistake. Try removing 'private'
 
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a_potato, you are right. I changed default setting by omitting :: after PRIVATE. Thank you for noticing it!
 
This is a little late, but it's worth mentioning that you can have the module entries to be private as default and then explicitly list the thing you want to expose publically. So you could have,

PRIVATE ! module members are private by default
PUBLIC :: BMatScal ! I want BMatScal to be publicThis way you can define internal constants and functions without worrying that they will collide with other modules members when you "use" them.
and then the use statement would recognize it.
 
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Allday, yes, you're right. This would be an option as well. Thank you.
 
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