Add initial benchmark for fftpack

example/bench1.f90

@@ -0,0 +1,41 @@
+program bench1
+use fftpack, only: zffti, zfftf, zfftb
+implicit none
+integer, parameter :: dp = kind(0.d0)
+complex(dp), allocatable :: z(:)
+real(dp), allocatable :: w(:), x(:)
+real(dp) :: err, time_init, time_forward, time_backward, t1, t2
+integer :: N
+
+N = 1024*1014*16
+
+allocate(x(N), z(N), w(4*N+15))
+call random_number(x)
+z = x
+
+print *, "Initializing"
+call cpu_time(t1)
+call zffti(N, w)
+call cpu_time(t2)
+time_init = t2-t1
+
+print *, "Forward"
+call cpu_time(t1)
+call zfftf(N, z, w)
+call cpu_time(t2)
+time_forward = t2-t1
+
+print *, "Backward"
+call cpu_time(t1)
+call zfftb(N, z, w)
+call cpu_time(t2)
+time_backward = t2-t1
+print *, "Done"
+
+err = maxval(abs(x-real(z/N,dp)))
+print *
+print *, "Error: ", err
+print *, "Init time: ", time_init
+print *, "Forward time: ", time_forward
+print *, "Backward time: ", time_backward
+end program

fpm.toml

@@ -13,7 +13,7 @@ keywords    = ["netlib", "fftpack", "fft"]
 [build]
 auto-executables = false
 auto-tests = false
-auto-examples = false
+auto-examples = true
 
 # Original test
 [[test]]