Hi, Nana

You must put in a file only the part of the system that contains celldm(1..6) and ibrav, and later run ibrav2cell.x < file.

For example, for hematite Fe2O3, I have the following for the SCF calculation (only the system part):

&SYSTEM

ibrav = 5

nat = 10

ntyp = 3

a = 5.175

cosab = 0.579005142

starting_magnetization(1) = -0.5

starting_magnetization(2) = 0.5

ecutwfc = 65

ecutrho = 780

occupations = "smearing"

degauss = 1.0e-03

smearing = "mv"

nspin = 2

/

For ibrav2cell, the file must be:

/

&SYSTEM

ibrav = 5

celldm(4) = 0.579005142

celldm(1) = 5.175

/

As you can see, I must change the input values a = 5.175 and cosab = 0.579... to celldm(1) and celldm(4) in this case.

After running ibrav2cell.x < hematite.in, I will have:

Unit cell (bohr):

2.374289937963323 -1.370796934817247 4.389110166534872

-0.000000000000000 2.741593869634127 4.389110166534872

-2.374289937963323 -1.370796934817247 4.389110166534872

Unit cell in units of alat (= 5.175000 bohr):

0.45879999 -0.26488830 0.84813723

-0.00000000 0.52977659 0.84813723

-0.45879999 -0.26488830 0.84813723

I hope this is useful for you.