Make not working on Mojave

[dlfivefifty]

[solver-mbook:~/Projects/FastTransforms] solver% export CC=gcc-8 && make
make lib
gcc-8 -Ofast  -march=native -mtune=native -I./src -I/usr/local/opt/openblas/include -I/usr/local/opt/fftw/include -shared -lm -fPIC -fopenmp src/transforms.c src/rotations.c src/permute.c src/drivers.c src/fftw.c -L/usr/local/opt/openblas/lib -L/usr/local/opt/fftw/lib -lm -lblas -lfftw3 -lfftw3_threads -o libfasttransforms.dylib
In file included from src/transforms.c:3:
src/ftinternal.h:4:10: fatal error: stdlib.h: No such file or directory
 #include <stdlib.h>
          ^~~~~~~~~~
compilation terminated.
In file included from /usr/local/opt/openblas/include/openblas_config.h:104,
                 from /usr/local/opt/openblas/include/cblas.h:5,
                 from src/fasttransforms.h:4,
                 from src/rotations.c:3:
/usr/local/Cellar/gcc/8.2.0/lib/gcc/8/gcc/x86_64-apple-darwin17.7.0/8.2.0/include-fixed/stdio.h:78:10: fatal error: _stdio.h: No such file or directory
 #include <_stdio.h>
          ^~~~~~~~~~
compilation terminated.
In file included from src/permute.c:3:
src/ftinternal.h:4:10: fatal error: stdlib.h: No such file or directory
 #include <stdlib.h>
          ^~~~~~~~~~
compilation terminated.
In file included from /usr/local/opt/openblas/include/openblas_config.h:104,
                 from /usr/local/opt/openblas/include/cblas.h:5,
                 from src/fasttransforms.h:4,
                 from src/drivers.c:3:
/usr/local/Cellar/gcc/8.2.0/lib/gcc/8/gcc/x86_64-apple-darwin17.7.0/8.2.0/include-fixed/stdio.h:78:10: fatal error: _stdio.h: No such file or directory
 #include <_stdio.h>
          ^~~~~~~~~~
compilation terminated.
In file included from /usr/local/opt/openblas/include/openblas_config.h:104,
                 from /usr/local/opt/openblas/include/cblas.h:5,
                 from src/fasttransforms.h:4,
                 from src/fftw.c:3:
/usr/local/Cellar/gcc/8.2.0/lib/gcc/8/gcc/x86_64-apple-darwin17.7.0/8.2.0/include-fixed/stdio.h:78:10: fatal error: _stdio.h: No such file or directory
 #include <_stdio.h>
          ^~~~~~~~~~
compilation terminated.
make[1]: *** [lib] Error 1
make: *** [all] Error 2

[MikaelSlevinsky]

This is the same compilation error that used to appear in Travis' macOS builds, even on High Sierra.

I fixed it via f623ae8, which I found from some other GitHub repository feeling the same effects.

I've never experienced this error on either of my macs, but look forward to it!

[MikaelSlevinsky]

Also, the default FT_FFTW_FLAGS is now FFTW_MEASURE, but this may be an unduly burdensome for live computations. (I think FFTW stores some of the microkernels it compares, so perhaps the overhead is just experienced the first time at fixed degree).

[dlfivefifty]

The FFT time is non-negligible, right? Why not use MKL which is apparently much faster?

[MikaelSlevinsky]

Could be used, but would require some modifications since MKL is incomplete. In particular, it doesn't implement real-to-complex transforms with split storage, halfcomplex-to-real transforms, or multidimensional real-to-real transforms. https://software.intel.com/en-us/mkl-developer-reference-c-using-fftw3-wrappers

[MikaelSlevinsky]

BTW, I added a proposal for Julia wrapper here JuliaApproximation/FastTransforms.jl@ee98f40

[dlfivefifty]

Fixed it!! Here's the instructions

1. Run (from https://stackoverflow.com/questions/52509602/cant-compile-c-program-on-a-mac-after-upgrade-to-mojave)

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg

to restore /usr/include and /usr/lib

2. Add

CFLAGS += -I/usr/include
LDFLAGS += -L/usr/lib

to Make.inc

[MikaelSlevinsky]

Is 2. necessary? are they not default search paths for gcc (which is why it can't find the headers to begin with)?

[dlfivefifty]

Probably: I tried without them.

[MikaelSlevinsky]

Fun fact that I've been experimenting with recently: you can compile one file into assembly using one compiler (gcc-8 on rotations.c => rotations.s) and then use a different compiler to turn the assembly into executables/libraries. Clang has significantly better control over OpenMP threads, which is pronounced for low degrees.

[dlfivefifty]

Actually, I just needed to rebuild gcc (I deleted /usr/local and started from scratch with homebrew)