kschan: use eigen instead of sparse13

[alkino]

kschan is using a sparse13 matrix to <fill the blank>, we replace it with a Eigen::SparseMatrix.

During the process we remove variables elms_ and diag_. diag_ was a list of all diagonal value accessed by direct raw pointers, elms_ were the useful values of the matrix store as direct raw pointers to internal of the matrix too.
We needed to remove it, because, with Eigen, the matrix can be relocated and so the pointers be invalidate.

A second change is to store the matrix as a value inside the class instead of a pointer.

We should have take care about the fact that sparse13 matrix are 1-indexed and Eigen is 0-indexed.

Last, we store the solver along the matrix Eigen::SparseLU. This is a sparse solver using the LU decomposition.

[azure-pipelines]

✔️ 7870b75 -> Azure artifacts URL

[azure-pipelines]

✔️ 7870b75 -> Azure artifacts URL

[nrnhines]

Nice. I suppose, eventually, this strategy can be used to eliminate sparse13 entirely. We'll just want to verify that performance is equal or better.

[azure-pipelines]

✔️ ca688b0 -> Azure artifacts URL

[azure-pipelines]

✔️ 8a05c9e -> Azure artifacts URL

[alkino]

@nrnhines results changed... again.

[azure-pipelines]

✔️ 72f7558 -> Azure artifacts URL

[github-actions]

NEURON ModelDB CI: launching for d2c2f77 via its drop url

[ohm314]

looks good to me

[azure-pipelines]

✔️ 211a7cb -> Azure artifacts URL

[alkino]

Last difference is

strdiff -0.985562 -0.985563
strdiff -49.3732 -49.3733
strdiff -0.0788185 -0.0788184
strdiff -0.00333632 -0.00333631

[azure-pipelines]

✔️ e5dca68 -> Azure artifacts URL

[alkino]

@nrnhines if you have some time to look at the difference in result of this PR, I can have a call with you to give you more explanation of the code.

[azure-pipelines]

✔️ 531c252 -> Azure artifacts URL

[azure-pipelines]

✔️ 72b7cdc -> Azure artifacts URL

[azure-pipelines]

✔️ baaf458 -> Azure artifacts URL

[azure-pipelines]

✔️ 9f21585 -> Azure artifacts URL

[nrnhines]

Last difference is

strdiff -0.985562 -0.985563
strdiff -49.3732 -49.3733
strdiff -0.0788185 -0.0788184
strdiff -0.00333632 -0.00333631

At the moment, this only appears from NEURON Code Coverage / Code Coverage (pull_request) Failing after 32m?
No other CI is failing and I'm not seeing the problem with

cmake .. -G Ninja -DCMAKE_INSTALL_PREFIX=install -DPYTHON_EXECUTABLE=`which python` -DNRN_ENABLE_TESTS=ON
ninja install
ctest -R hoctests::test_neurondemo_py

Have you ever seen the CI error on your machine? If so, what cmake did you use.
The cmake of that CI appears to be

PYTHON_MIN_NAME: python3.8
PYTHON_MID_NAME: python3.10
PYTHON_MAX_NAME: python3.11
MUSIC_INSTALL_DIR: /opt/MUSIC

export CC=gcc 
export CXX=g++
export PYTHON_MIN=$(which $PYTHON_MIN_NAME)
export PYTHON_MID=$(which $PYTHON_MID_NAME)
export PYTHON_MAX=$(which $PYTHON_MAX_NAME)
mkdir build && cd build
cmake_args=(-G Ninja \
    -DCMAKE_BUILD_TYPE=Debug \   
    -DCMAKE_C_COMPILER="$CC" \   
    -DCMAKE_CXX_COMPILER="$CXX" \
    -DNRN_ENABLE_BACKTRACE=ON \ 
    -DNRN_ENABLE_CORENEURON=ON \
    -DNRN_ENABLE_COVERAGE=ON \  
    -DNRN_ENABLE_INTERVIEWS=ON \
    -DNRN_ENABLE_MPI=ON \
    -DNRN_ENABLE_PERFORMANCE_TESTS=OFF \
    -DNRN_ENABLE_PROFILING=ON \
    -DNRN_ENABLE_PYTHON=ON \
    -DNRN_ENABLE_PYTHON_DYNAMIC=ON \
    -DNRN_PYTHON_DYNAMIC="${PYTHON_MIN};${PYTHON_MAX}" \
    -DNRN_PYTHON_EXTRA_FOR_TESTS=${PYTHON_MID} \
    -DNRN_ENABLE_TESTS=ON \
    -DNRN_ENABLE_MUSIC=ON \
    -DCMAKE_PREFIX_PATH="${MUSIC_INSTALL_DIR}" \
    -DMUSIC_ROOT="${MUSIC_INSTALL_DIR}")
cmake .. "${cmake_args[@]}"

[sonarcloud]

Quality Gate passed

Issues
0 New issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[azure-pipelines]

✔️ 03ab16f -> Azure artifacts URL

[bbpbuildbot]

Logfiles from GitLab pipeline #195352 (:no_entry:) have been uploaded here!

Status and direct links:

• ✅ mac_m1_cmake_build: [cmake, ON, OFF, OFF, address]
• ✅ spack_setup
• ✅ build:nmodl
• ✅ build:neuron:nmodl:intel:legacy
• ✅ build:neuron:nmodl:intel:shared
• ✅ build:neuron:nmodl:nvhpc:acc:legacy
• ✅ build:neuron:nmodl:nvhpc:acc:shared
• ✅ build:neuron:nmodl:nvhpc:omp:legacy
• ✅ build:neuron:nmodl:nvhpc:omp
• ✅ test:neuron:nmodl:intel:legacy
• ✅ test:neuron:nmodl:intel:shared
• ✅ test:neuron:nmodl:nvhpc:acc:legacy
• ✅ test:neuron:nmodl:nvhpc:acc:shared
• ⛔ test:neuron:nmodl:nvhpc:omp:legacy
• ⛔ test:neuron:nmodl:nvhpc:omp