/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/ is in libsundials-serial-dev 2.5.0-3+b3.
This file is owned by root:root, with mode 0o755.
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/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/README
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasBruss_ASAp_kry_bbd_p.c
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasBruss_FSA_kry_bbd_p.c
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasBruss_kry_bbd_p.c
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasFoodWeb_kry_bbd_p.c
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasFoodWeb_kry_p.c
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasHeat2D_FSA_kry_bbd_p.c
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasHeat2D_kry_bbd_p.c
/usr/share/doc/libsundials-serial-dev/examples/idas/parallel/idasHeat2D_kry_p.c