Initilalising an array with a sequence in Fortran

问题

I am currently working on translating some legacy fortran code and I am having a hard time understanding a particular line in the code. The compiler also seems to find this line weird and throws out an error. From what I understand it is trying to initialize an array by sequencing 1 to 9 by increments of 1 and filling up the array matrix with this sequence in column major form.

program arrayProg

  integer :: matrix(3,3), i , j !two dimensional real array

  matrix = reshape((/1:9:1/), (/3,3/))

end program arrayProg

Is this syntax acceptable in fortran? (It has to be because it comes from the legacy code) Am I misunderstanding what the line does?

回答1:

The syntax is incorrect and such code cannot be compiled by a Fortran compiler, unless it implements some non-standard extension.

Intel Fortran accepts this:

 A colon-separated triplet (instead of an implied-DO loop) to specify a range of values and a stride; for example, the following two array constructors are equivalent:
1       INTEGER D(3)
2       D = (/1:5:2/)              ! Triplet form - also [1:5:2]
3       D = (/(I, I=1, 5, 2)/)     ! implied-DO loop form

from https://software.intel.com/en-us/node/678554

To generate a sequence in a standard way one uses an implied do loop like

 (/ (i, i=1,9) /)

the reshape than just changes the 1D array into a 2D one in column major order as you guessed.

来源：https://stackoverflow.com/questions/46698017/initilalising-an-array-with-a-sequence-in-fortran