Follow these simple steps on an Ubuntu system: 1/ download cvode from https://computation.llnl.gov/casc/sundials/download/download.html 2/./configure CC=gcc CFLAGS=-O3 F77=gfortran FFLAGS=-O3 --enable-examples --libdir=/usr/lib --includedir=/usr/include/ 3/ make 4/ As root: make install 5/ ln -s /usr/lib/libsundials_cvode.a /usr/lib/libcvode.a 6/ ln -s /usr/lib/libsundials_nvecserial.a /usr/lib/libcvodeserial.a 5/ Compile simply as gcc -O3 -o hcrt hcrt_cvode.c -lm -lcvode -lcvodeserial gcc -O3 -o lc LC_SFO.c -lm -lcvode -lcvodeserial or type make