I noticed that the subroutine sprsin in numerical recipes produces catastrophic error if compiled with ifort 15.
The problem seems due to the line
sa%jcol=pack(spread(arth(1,1,n),1,n),mask)
It is possible to reproduce the error by compiling the code test_err1.f90
ifort test_err1.f90
./a.out
At the same time I found that this line
sa%irow = pack(spread(arth(1,1,NDIM),2,NDIM),mask(:,:))
in test_err2.f90 produce bad results.
gfortran compiler and old version of ifort produce correct results.
I use Ubuntu 14.04.2 LTS 64bit