general fortran question

[siemer_michael]

Hi, I am making the move from matlab to fortran and have what I think is a trivial question for people having used fortran:

Supposed I have a matrix x(N,M,Q) where N,M,Q are the dimensions. Now, I would like to save the third dimension for the first element of the first and second dimension of this matrix in a vector, in matlab I would write

vector=squeeze(x(1,1,:))

vector is then in matlab a Q by 1 vector.

now in fortran if I have

real*8 N,M,Q

double precision, dimension(N,M,Q):: x

double precision, dimension(Q):: vector

and then write

vector=x(1,1,:)

I receive an error message. What is the simplest way of doing in fortran what squeeze is doing for matlab?

Thank you.

[DavidWhite · Accepted solution]

I think you need to use RESHAPE:

vector = RESHAPE (x(1,1,:), (/Q/))

Regards,

David

[IanH]

The variables for your array dimensions (N, M and Q) should be type integer.

In future posts please quote the actual error message text.

[bmchenry]

i was going to say that it needed to be integer too...
however when checking and looking at the Fortran help file for array shape specifiers it states:
"The expressions can have a positive, negative or zero bvalue. If nescessary, the value is converted to an integer"
This appears to be code from a subroutine? which must be called with the arguments N,M,Q
so I'd ventue to guess the subroutine arguments has a type mismatch (the N,M,Q)?
Or
if in a main program then where is N,M,Q values declared?
Is this an assumed shape array (in a subroutine?) or an allocatable array??
if allocatable you need a different declaration (see section in help manual on Declaration for Arrays.