No such file or directory: 'cmake' after Expression

Question

Hi All,

thanks in advance for helping me out.

I'm having trouble with the following Expression:

import dolfin as dlfn
...
u2 = dlfn.Expression(('(A*time+B)*length','0.0','0.0'), A=-0.08, B=0.05, time=0.0, length=xlength, degree=1)

Normally an Expression of the form

tr = dlfn.Expression(('A','0.0','0.0'), A=10.0, degree=1)

works well. What is wrong with the first one? It should be possible to have more than one parameter. Also the Expression

f = Expression('A*sin(x[0]) + B*cos(x[1])', A=2.0, B=Constant(4.0))

from the documentation https://fenicsproject.org/olddocs/dolfin/2016.2.0/python/programmers-reference/functions/expression/Expression.html does not work.
What am I missing here?

Thanks, Philipp

See the whole error message below:
--- Instant: compiling ---
Traceback (most recent call last):

File "", line 1, in
runfile('/Users/philippdiercks/my-fenics-projects/Damage/ratenform.py', wdir='/Users/philippdiercks/my-fenics-projects/Damage')

File "/Users/philippdiercks/anaconda2/lib/python2.7/site-packages/spyder/utils/site/sitecustomize.py", line 866, in runfile
execfile(filename, namespace)

File "/Users/philippdiercks/anaconda2/lib/python2.7/site-packages/spyder/utils/site/sitecustomize.py", line 94, in execfile
builtins.execfile(filename, *where)

File "/Users/philippdiercks/my-fenics-projects/Damage/ratenform.py", line 111, in
u2 = dlfn.Expression(('(Atime+B)length','0.0','0.0'), A=-0.08, B=0.05, time=0.0, length=xlength, degree=1)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/dolfin/functions/expression.py", line 654, in new
mpi_comm=kwargs.get("mpi_comm"))

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/dolfin/compilemodules/expressions.py", line 214, in compile_expressions
mpi_comm=mpi_comm)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/dolfin/compilemodules/expressions.py", line 141, in compile_expression_code
mpi_comm=mpi_comm)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/dolfin/compilemodules/jit.py", line 68, in mpi_jit
return local_jit(*args, **kwargs)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/dolfin/compilemodules/compilemodule.py", line 472, in compile_extension_module
**instant_kwargs)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/instant/build.py", line 578, in build_module
build_system)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/instant/build.py", line 150, in recompile
ret, output = get_status_output(cmd)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/instant/output.py", line 150, in get_status_output
stderr=subprocess.STDOUT)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/subprocess32.py", line 825, in init
restore_signals, start_new_session)

File "/Users/philippdiercks/anaconda2/envs/fenicsproject/lib/python2.7/site-packages/subprocess32.py", line 1574, in _execute_child
raise child_exception_type(errno_num, err_msg)

OSError: [Errno 2] No such file or directory: 'cmake'

Answer 1

Instant is using cmake at runtime, so you need to install it and make sure it is available in PATH.

Comments

Hi,

thank you for your answer. Unfortunately I don't understand what seems to be the problem here. I have installed FEniCS via Anaconda on MacOS. Using conda list in the active fenicsproject-environment I get

cmake                     3.8.0                         0    conda-forge

So it should be available. Also what I do not understand is: Why should

tr = dlfn.Expression(('A','0.0','0.0'), A=10.0, degree=1)

work and the other line not, if there is something wrong with the PATH.
Also which PATH do you mean exactly and how can I access it?
(sorry for my lack of knowledge, I'm still new to this)

Thanks, Philipp

---

What do you get when you run the following commands?

which cmake
cmake --version

---

by the command

which cmake

I get the path to cmake

/Users/philippdiercks/anaconda2/envs/fenicsproject/bin/cmake

by running

cmake --version

I get

cmake version 3.8.0

---

Looks fine. I don't know what the problem is. You can try to report it to the FEniCS support mailing list: fenics-support@googlegroups.com.

---

The actual problem was that I used the "default" spyder which is installed automatically when installing Anaconda. Somehow the PATH can't be set correctly.

I had to install spyder in the Anaconda environment "fenicsproject".
Now all packages and modules are known by spyder.

---

Good.

Btw, it would have been nice if you had mentioned in your question that you where trying to use this in Spyder. That would have made it easier to give a proper answer.