These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.28 s (backtrack: 0/20).

[ebuild  N     ] virtual/fortran-0-r1::gentoo  USE="openmp" 0 KiB
[ebuild  N     ] acct-group/munge-0-r2::gentoo  0 KiB
[ebuild  N     ] sci-libs/openblas-0.3.34::gentoo  USE="openmp -cpudetection -index64 -pthread -relapack -test" 24734 KiB
[ebuild  N     ] acct-user/munge-0-r2::gentoo  0 KiB
[ebuild  N     ] x11-libs/libpciaccess-0.19::gentoo  USE="zlib -static-libs" 64 KiB
[ebuild  N     ] sys-apps/hwloc-2.12.2:0/15::gentoo  USE="X cairo cpuid pci -cuda -debug -doc -l0 -nvml -rocm (-selinux) -static-libs -svg -udev -valgrind -xml" VIDEO_CARDS="-nvidia" 5504 KiB
[ebuild  N     ] sys-auth/munge-0.5.18::gentoo  USE="-debug -gcrypt -static-libs" 456 KiB
[ebuild  N     ] sys-cluster/pmix-6.1.0::gentoo  USE="munge -debug -pmi" 10552 KiB
[ebuild  N     ] sys-cluster/prrte-4.1.0-r1:0/4::gentoo  10247 KiB
[ebuild  N     ] sys-cluster/openmpi-5.0.9-r1::gentoo  USE="fortran -cma -cuda -peruse -romio -valgrind" OPENMPI_FABRICS="-knem -ofed" OPENMPI_RM="-pbs (-slurm)" 29650 KiB
[ebuild  N     ] virtual/mpi-2.0-r8::gentoo  USE="fortran threads -cxx -nullmpi -romio" 0 KiB
[ebuild  N     ] sci-libs/lapack-3.12.1-r2::gentoo  USE="deprecated flexiblas lapacke -doc -eselect-ldso -index64 -test" 7879 KiB
[ebuild  N     ] sci-libs/flexiblas-3.5.0::gentoo  USE="openblas openmp system-blas -blis -index64 -mkl -tbb -test" 80741 KiB
[ebuild  N     ] sci-libs/blas-lapack-aux-wrapper-6::gentoo  USE="-index64 -test" 10 KiB
[ebuild  N     ] virtual/lapack-3.10-r1::gentoo  USE="flexiblas -eselect-ldso -index64" 0 KiB
[ebuild  N     ] sci-libs/scalapack-2.2.2-r1::gentoo  USE="-static-libs -test" 4658 KiB

Total: 16 packages (16 new), Size of downloads: 174489 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by sci-libs/scalapack-2.2.2-r1::gentoo
# required by =sci-libs/scalapack-2.2.2-r1 (argument)
>=virtual/mpi-2.0-r8 fortran
# required by virtual/mpi-2.0-r8::gentoo
# required by sci-libs/scalapack-2.2.2-r1::gentoo
# required by =sci-libs/scalapack-2.2.2-r1 (argument)
>=sys-cluster/openmpi-5.0.9-r1 fortran