Examples

Using FTI_Snapshot
Using FTI Checkpoint
Using FTI_Realloc with Fortran and Intrinsic Types
Using FTI_Realloc with Fortran and Derived Types

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Using FTI_Snapshot

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#include <stdlib.h>
#include <fti.h>

int main(int argc, char** argv){
    MPI_Init(&argc, &argv);
    char* path = "config.fti"; //config file path
    FTI_Init(path, MPI_COMM_WORLD);
    int world_rank, world_size; //FTI_COMM rank & size
    MPI_Comm_rank(FTI_COMM_WORLD, &world_rank);
    MPI_Comm_size(FTI_COMM_WORLD, &world_size);

    int *array = malloc(sizeof(int) * world_size);
    int number = world_rank;
    int i = 0;
    //adding variables to protect
    FTI_Protect(1, &i, 1, FTI_INTG);
    FTI_Protect(2, &number, 1, FTI_INTG);
    for (; i < 100; i++) {
        FTI_Snapshot();
        MPI_Allgather(&number, 1, MPI_INT, array,
		      1, MPI_INT, FTI_COMM_WORLD);
	number += 1;
    }
    free(array);
    FTI_Finalize();
    MPI_Finalize();
    return 0;
}

DESCRIPTION

FTI_Snapshot() makes a checkpoint by given time and also recovers data after a failure, thus makes the code shorter. Checkpoints intervals can be set in configuration file (see: ckpt_L1 - ckpt_L4).

Using FTI_Checkpoint

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#include <stdlib.h>
#include <fti.h>
#define ITER_CHECK 10

int main(int argc, char** argv){
    MPI_Init(&argc, &argv);
    char* path = "config.fti"; //config file path
    FTI_Init(path, MPI_COMM_WORLD);
    int world_rank, world_size; //FTI_COMM rank & size
    MPI_Comm_rank(FTI_COMM_WORLD, &world_rank);
    MPI_Comm_size(FTI_COMM_WORLD, &world_size);

    int *array = malloc(sizeof(int) * world_size);
    int number = world_rank;
    int i = 0;
    //adding variables to protect
    FTI_Protect(1, &i, 1, FTI_INTG);
    FTI_Protect(2, &number, 1, FTI_INTG);
    if (FTI_Status() != 0) {
        FTI_Recover();
    }
    for (; i < 100; i++) {
        if (i % ITER_CHECK == 0) {
            FTI_Checkpoint(i / ITER_CHECK + 1, 2);
        }
        MPI_Allgather(&number, 1, MPI_INT, array,
		      1, MPI_INT, FTI_COMM_WORLD);
	number += 1;
    }
    free(array);
    FTI_Finalize();
    MPI_Finalize();
    return 0;
}

DESCRIPTION

FTI_Checkpoint() allows to checkpoint at precise application intervals. Note that when using FTI_Checkpoint(), ckpt_L1, ckpt_L2, ckpt_L3 and ckpt_L4 are not taken into account.

Using FTI_Realloc with Fortran and Intrinsic Types

program test_fti_realloc
    use fti
    use iso_c_binding
    implicit none
    include 'mpif.h'

    integer, parameter          :: dp=kind(1.0d0)
    integer, parameter          :: N1=128*1024*25  !> 25 MB / Process
    integer, parameter          :: N2=128*1024*50  !> 50 MB / Process
    integer, parameter          :: N11 = 128       
    integer, parameter          :: N12 = 1024
    integer, parameter          :: N13 = 25
    integer, parameter          :: N21 = 128       
    integer, parameter          :: N22 = 1024
    integer, parameter          :: N23 = 50
    integer, target             :: FTI_COMM_WORLD
    integer                     :: ierr, status

    real(dp), dimension(:,:,:), pointer :: arr
    type(c_ptr)				:: arr_c_ptr
    real(dp), dimension(:,:,:), pointer :: tmp
    integer(4), dimension(:), pointer   :: shape

    allocate(arr(N11,N12,N13))
    allocate(shape(3))
    
    !> INITIALIZE MPI AND FTI    
    call MPI_Init(ierr)
    FTI_COMM_WORLD = MPI_COMM_WORLD
    call FTI_Init('config.fti', FTI_COMM_WORLD, ierr)
    
    !> PROTECT DATA AND ITS SHAPE
    call FTI_Protect(0, arr, ierr)
    call FTI_Protect(1, shape, ierr)
    
    call FTI_Status(status)

    !> EXECUTE ON RESTART
    if ( status .eq. 1 ) then
        !> REALLOCATE TO SIZE AT CHECKPOINT
        arr_c_ptr = c_loc(arr(1,1,1))
        call FTI_Realloc(0, arr_c_ptr, ierr)
        call FTI_recover(ierr)
        !> RESHAPE ARRAY
        call c_f_pointer(arr_c_ptr, arr, shape)
        call FTI_Finalize(ierr)
        call MPI_Finalize(ierr)
        STOP
    end if
    
    !> FIRST CHECKPOINT
    call FTI_Checkpoint(1, 1, ierr)

    !> CHANGE ARRAY DIMENSION
    !> AND STORE IN SHAPE ARRAY
    shape = [N21,N22,N23]
    allocate(tmp(N21,N22,N23))
    tmp(1:N11,1:N12,1:N13) = arr
    deallocate(arr)
    arr => tmp
    
    !> TELL FTI ABOUT THE NEW DIMENSION
    call FTI_Protect(0, arr, ierr)

    !> SECOND CHECKPOINT
    call FTI_Checkpoint(2,1, ierr)
   
    !> SIMULATE CRASH
    call MPI_Abort(MPI_COMM_WORLD,-1,ierr)
end program

Using FTI_Realloc with Fortran and Derived Types

program test_fti_realloc
    use fti
    use iso_c_binding
    implicit none
    include 'mpif.h'

    !> DEFINE DERIVED TYPE
    type :: polar 
        real :: radius
        real :: phi
    end type

    integer, parameter          :: dp=kind(1.0d0)
    integer, parameter          :: N1=128*1024*25  !> 25 MB / Process
    integer, parameter          :: N2=128*1024*50  !> 50 MB / Process
    integer, parameter          :: N11 = 128       
    integer, parameter          :: N12 = 1024
    integer, parameter          :: N13 = 25
    integer, parameter          :: N21 = 128       
    integer, parameter          :: N22 = 1024
    integer, parameter          :: N23 = 50
    integer, target             :: FTI_COMM_WORLD
    integer                     :: ierr, status
    type(FTI_type)              :: FTI_Polar

    type(c_ptr)                            :: cPtr
    type(polar), dimension(:,:,:), pointer :: arr
    type(polar), dimension(:,:,:), pointer :: tmp
    integer(4), dimension(:), pointer      :: shape

    !> INITIALIZE FTI TYPE 'FTI_POLAR'
    call FTI_InitType(FTI_Polar, 2*4, ierr)
    
    allocate(arr(N11,N12,N13))
    allocate(shape(3))
    
    !> INITIALIZE MPI AND FTI
    call MPI_Init(ierr)
    FTI_COMM_WORLD = MPI_COMM_WORLD
    call FTI_Init('config.fti', FTI_COMM_WORLD, ierr)

    !> PROTECT DATA AND ITS SHAPE
    call FTI_Protect(0, c_loc(arr), size(arr),FTI_Polar, ierr)
    call FTI_Protect(1, shape, ierr)

    call FTI_Status(status)
    
    !> EXECUTE ON RESTART
    if ( status .eq. 1 ) then
        !> REALLOCATE TO DIMENSION AT LAST CHECKPOINT
        cPtr = c_loc(arr)
        call FTI_Realloc(0, cPtr, ierr) !> PASS DATA AS C-POINTER
        call FTI_recover(ierr)
        call c_f_pointer(cPtr, arr, shape) !> CAST BACK TO F-POINTER
        call FTI_Finalize(ierr)
        call MPI_Finalize(ierr)
        STOP
    end if

    !> FIRST CHECKPOINT
    call FTI_Checkpoint(1, 1, ierr)

    !> CHANGE ARRAY DIMENSION
    !> AND STORE IN SHAPE ARRAY
    shape = [N21,N22,N23]
    allocate(tmp(N21,N22,N23))
    tmp(1:N11,1:N12,1:N13) = arr
    deallocate(arr)
    arr => tmp

    !> TELL FTI ABOUT THE NEW DIMENSION
    call FTI_Protect(0, c_loc(arr), size(arr), FTI_Polar, ierr)
    
    !> SECOND CHECKPOINT
    call FTI_Checkpoint(2,1, ierr)
   
    !> SIMULATE CRASH
    call MPI_Abort(MPI_COMM_WORLD,-1,ierr)
end program