fortran95

I decided to learn the fortran95 language (reason why is not important). However being a beginner I ran into a weird problem I really can't explain, therefor I need help. I have the insertion sort algorithm: subroutine insertion_sort_REAL4(array, array_len) implicit none !parameners integer :: array_len real (kind=4), dimension(array_len) :: array !variables integer :: i,key,hole_pos do i = 0,array_len key = array(i) hole_pos = i; do while ((hole_pos > 0.0) .and. (key < array(hole_pos - 1))) array(hole_pos) = array(hole_pos - 1) hole_pos = hole_pos - 1 end do array(hole_pos) = key end do

I'm new in the area of Fortran programming and after testing a few programs I already got a feeling of how to write programs. Now I was trying me on a bit harder program and I run into a problem I couldn't solve by myself. I already googled about the problem but I couldn't find an adequate answer ... So I thought maybe there are one or two Fortran programmers which can give me a hand in solving this problem. The program is very simple it just multiplies two matrices with each other. I was trying to write a function which performs the task and returns the result matrix back to the invoker. To

The following code gives segmentation error when compiled with pgf90 on the Linux system, while is run successfully when I used the Intel Visual FORTRAN on Windows. program main implicit none integer:: a(3), b(3) ,c(3) a=[3, 4, 5] b=[1, 2, 3] call sub(a,b,c) write(*,*)'a+b = ',c end program main subroutine sub(a,b,c) implicit none integer, intent(in)::a(:),b(:) integer, intent(out)::c(:) c=a+b end subroutine sub Any explanation for this ? When you call a subroutine which has assumed shape dummy arguments (as is the case in this program), an explicit interface is required. The easiest way to

Hopefully you could me explaining this thing. I'm working with Fortran and actually writing my code on CFD topic, and below (just for sake of simplicity and just for example) are short explanations of my case: I should use one 2D array A(i,j) and one 1D array B(i) I have to do 2 times looping, which is the first looping should be 50,000 times and the second one is 5 times (can't be changed). The point number 2 above should be looped 10,000 times. I write the codes with 2 versions (I called them Prog_A and Prog_B). The first one is as shown below: PROGRAM PROG_A REAL*8, DIMENSION(50000,5):: A

I found this code to behave unexpectedly module testmodule integer, parameter :: LCHARS = 50 contains subroutine init() call foobar("foobar") end subroutine subroutine foobar(s) character(len=*), intent(in) :: s call bar(s) end subroutine subroutine bar(str) character(len=LCHARS), intent(in) :: str print *, str end subroutine end module program foo use testmodule call init() end program This code prints garbage which is compiler dependent. I see the problem being the fact that I am jumping through a routine with len=* for a string argument, which is then passed to a routine with specified

This program crashes with Illegal instruction: 4 on MacOSX Lion and ifort (IFORT) 12.1.0 20111011 program foo real, pointer :: a(:,:), b(:,:) allocate(a(5400, 5400)) allocate(b(5400, 3600)) a=1.0 b(:, 1:3600) = a(:, 1:3600) print *, a print *, b deallocate(a) deallocate(b) end program The same program works with gfortran. I don't see any problem. Any ideas ? Unrolling the copy and performing the explicit loop over the columns works in both compilers. Note that with allocatable instead of pointer I have no problems. The behavior is the same if the statement is either inside a module or not. I