C and Fortran compilers must be in your PATH. If configure says that you have no working compiler, well, you have no working compiler, at least not in your PATH, and not among those recognized by configure.
Both AMD and Intel CPUs, 32-bit and 64-bit, are supported and work, either in 32-bit emulation and in 64-bit mode. 64-bit executables can address a much larger memory space than 32-bit executable, but there is no gain in speed. Beware: the default integer type for 64-bit machine is typically 32-bit long. You should be able to use 64-bit integers as well, but it is not guaranteed to work and will not give any advantage anyway.
Currently, configure supports Intel (ifort), NAG (nagfor), PGI (pgf90) and gfortran compilers. Pathscale, Sun Studio, AMD Open64, are no longer supported after v.6.2: g95, since v.6.1.
Both Intel MKL and AMD acml mathematical libraries are supported, the former much better than the latter.
It is usually convenient to create semi-statically linked executables (with only libc, libm, libpthread dynamically linked). If you want to produce a binary that runs on different machines, compile it on the oldest machine you have (i.e. the one with the oldest version of the operating system).
You need at least gfortran v.4.4 or later to properly compile QUANTUM ESPRESSO.
"There is a known incompatibility problem between different calling convention for Fortran functions that return complex values [...] If your code crashes during a call to zdotc, recompile QUANTUM ESPRESSO using the internal BLAS and LAPACK routines (using configure options -with-internal-blas and -with-internal-lapack) to see if the problem disappears; or, add the -ff2c flag" (info by Giovanni Pizzi, Jan. 2013).
If you want to use MKL libraries together with gfortran, link -lmkl_gf_lp64, not -lmkl_intel_lp64 (and the like for other architectures).
IMPORTANT NOTE: ifort versions earlier than v.15 miscompile the new
XML code in QE v.6.4 and later. Please install this patch:
The Intel compiler ifort http://software.intel.com/ produces fast executables, at least on Intel CPUs, but not all versions work as expected. In case of trouble, update your version with the most recent patches. Since each major release of ifort differs a lot from the previous one, compiled objects from different releases may be incompatible and should not be mixed.
The Intel compiler is no longer free for personal usage, but it is still for students and open-source contributors (https://software.intel.com/en-us/qualify-for-free-software).
If configure doesn't find the compiler, or if you get Error loading shared libraries at run time, you may have forgotten to execute the script that sets up the correct PATH and library path. Unless your system manager has done this for you, you should execute the appropriate script - located in the directory containing the compiler executable - in your initialization files. Consult the documentation provided by Intel.
The warning: feupdateenv is not implemented and will always fail, can be safely ignored. Warnings on ``bad preprocessing option'' when compiling iotk and complains about ``recommended formats'' may also be ignored.
configure properly detects only recent (v.12 or later) MKL libraries,
as long as the $MKLROOT environment variable is set in the current shell.
Normally this environment variable is set by sourcing the Intel MKL or Intel
Parallel Studio environment script.
By default the non-threaded version of MKL is linked, unless option
configure -with-openmp is specified. In case of trouble,
refer to the following web page to find the correct way to link MKL:
For parallel (MPI) execution on multiprocessor (SMP) machines, set the environment variable OMP_NUM_THREADS to 1 unless you know what you are doing. See Sec.3 for more info on this and on the difference between MPI and OpenMP parallelization.
If you get a mysterious "too many communicators" error and a
subsequent crash: there is a bug in Intel MPI and MKL 2016 update 3.
See this thread and the links quoted therein:
export MKL_DEBUG_CPU_TYPE=5which gives an additional 10-20% speedup with MKL 2020, while for earlier versions the speedup is greater than 200%. [...] Another note, there seem to be problems using FFTW interface of MKL with AMD cpus. To get around this problem, one has to additionally set
export MKL_CBWR=AUTO`` (Info by Tobias Klöffel, Feb. 2020)
Apart from such problems, QUANTUM ESPRESSO compiles and works on all non-buggy, properly configured hardware and software combinations. In some cases you may have to recompile MPI libraries: not all MPI installations contain support for the Fortran compiler of your choice (or for any Fortran compiler at all!).
If QUANTUM ESPRESSO does not work for some reason on a PC cluster, try first if it works in serial execution. A frequent problem with parallel execution is that QUANTUM ESPRESSO does not read from standard input, due to the configuration of MPI libraries: see Sec.3.4. If you are dissatisfied with the performances in parallel execution, see Sec.3 and in particular Sec.3.4.
Another option: use MinGW/MSYS. Download the installer from https://osdn.net/projects/mingw/, install MinGW, MSYS, gcc and gfortran. Start a shell window; run "./configure"; edit make.inc; uncommenting the second definition of TOPDIR (the first one introduces a final "/" that Windows doesn't like); run "make". Note that on some Windows the code fails when checking that tmp_dir is writable, for unclear reasons.
Another option is Cygwin, a UNIX environment which runs under Windows: see
Windows-10 users may also enable the Windows Subsystem for Linux (see here:
https://docs.microsoft.com/en-us/windows/wsl/install-win10), install a Linux distribution, compile QUANTUM ESPRESSO as on Linux. It works very well.
As a final option, one can use Quantum Mobile:
Mac OS-X machines with gfortran or with the Intel compiler ifort and MKL libraries should work, but "your mileage may vary", depending upon the specific software stack you are using. Parallel compilation with OpenMPI should also work.
Gfortran information and binaries for Mac OS-X here: http://hpc.sourceforge.net/ and https://wiki.helsinki.fi/display/HUGG/GNU+compiler+install+on+Mac+OS+X.
Mysterious crashes in zdotc are due to a known incompatibility of complex functions with some optimized BLAS. See the "Linux PCs with gfortran" paragraph.