Revise tensorial form

[mforets]

• Adds another method for generate_tensor_form, as it was discussed in Computation of Full Tensorial Bernstein Form (general discussion) #3.
• Update REQUIRE.
• I notice that multivariate_tensor basically used the same code as kron, so we can refactor the code from generate_tensor_form and use the different algorithms.

[roccaa]

What does this checks failing means ? Is it critical ?

[roccaa]

It seems ok for me. I will run this on my laptop around 17h and accept it.

[mforets]

What does this checks failing means ? Is it critical ?

Yes, we (at least try to) solve the failing checks before merging. To see what is going on, see that there are two rows,

• continuous-integration/travis-ci/pr — The Travis CI build failed this tests the PR after merging
• continuous-integration/travis-ci/push — The Travis CI build failed this tests only this branch mforets/tensor_nloops

on the box "All checks have failed" if i click on "Details" i see the build jobs, then you click on one of the failing jobs and there is a the full job log in a terminal. The problem seems to be with my choice of version for the dependency RecursiveArrayTools,

27.06s$ julia --color=yes -e "if VERSION < v\"0.7.0-DEV.5183\" || (!isfile(\"Project.toml\") && !isfile(\"JuliaProject.toml\")); Pkg.clone(pwd()); end"
INFO: Initializing package repository /home/travis/.julia/v0.6
INFO: Cloning METADATA from https://github.com/JuliaLang/METADATA.jl
INFO: Cloning BernsteinExpansions from /home/travis/build/JuliaReach/BernsteinExpansions.jl
INFO: Computing changes...
ERROR: fixed packages introduce conflicting requirements for RecursiveArrayTools: 
         BernsteinExpansions requires versions [0.17.0,∞) [none of the available versions can satisfy this requirement]
       available versions are 0.0.1, 0.0.2, 0.0.3, 0.1.0, 0.1.1, 0.1.2, 0.2.0, 0.3.0, 0.4.0, 0.4.1, 0.5.0, 0.6.0, 0.6.1, 0.7.0, 0.7.1, 0.8.0, 0.9.0, 0.10.0, 0.10.1, 0.11.0, 0.11.1, 0.11.2, 0.12.0, 0.12.1, 0.12.2, 0.12.3, 0.12.4, 0.13.0, 0.13.1, 0.14.0, 0.14.1, 0.14.3, 0.14.4, 0.14.5, 0.14.6 and 0.15.0

For now let's remove the version number and let it choose the one it fits for each julia version automatically.

[mforets]

It seems ok for me.

Thanks