Pardiso.jl
The Pardiso.jl package provides an interface for using PARDISO 5.0 and Intel MKL PARDISO from the Julia language. You cannot use Pardiso.jl
without either having a valid license for PARDISO or having the MKL library installed. This package is available free of charge and in no way replaces or alters any functionality of the linked libraries.
Installation
The package itself is installed with Pkg.add("Pardiso")
but you also need to follow the installation instructions below to install a working PARDISO library.
MKL PARDISO
- Set the
MKLROOT
environment variable. See the MKL getting started manual for a thorough guide how to set this variable correctly. - Run
Pkg.build("Pardiso")
PARDISO 5.0
Windows
- Put the PARDISO library
libpardiso500-WIN-X86-64.dll
in thedeps
folder. - Run
Pkg.build("Pardiso")
UNIX / macOS
- Put the PARDISO library
libpardiso500-GNUXXX-X86-64.so
orlibpardiso500-MACOS-X86-64.dylib
in thedeps
folder located in~/.julia/v0.x/Pardiso
. - Install a (fast) installation of a BLAS and LAPACK (this should preferably be single threaded since PARDISO handles threading itself).
- Make sure OpenMP is installed.
- Make sure that the version of
gfortran
corresponding to the pardiso library is installed. - Run
Pkg.build("Pardiso")
Special macOS instructions
For macOS the following (exact) paths need to exist:
/usr/local/lib/libgfortran.3.dylib
/usr/local/lib/libgomp.1.dylib
/usr/local/lib/libquadmath.0.dylib
If these do not exist, you can create symlinks from the current location of the libraries.
If you are using homebrew, these libraries exist in the gcc installation at e.g. /usr/local/Cellar/gcc/7.2.0/lib/gcc/7
.
Creating a symlink would then look like:
ln -s /usr/local/Cellar/gcc/7.2.0/lib/gcc/7/libgfortran.dylib /usr/local/lib/libgfortran.3.dylib
Basic Usage
This section will explain how to solve equations using Pardiso.jl
with the default settings of the library. For more advanced usage there is a section further down.
Creating the PardisoSolver
A PardisoSolver
is created with PardisoSolver()
for solving with PARDISO 5.0 or MKLPardisoSolver()
for solving with MKL PARDISO. This object will hold the settings of the solver and will be passed into the solve functions. In the following sections an instance of a PardisoSolver
or a MKLPardisoSolver()
will be referred to as ps
.
Solving
Solving equations is done with the solve
and solve!
functions. They have the following signatures:
solve(ps, A, B)
solvesAX=B
and returnsX
solve!(ps, X, A, B)
solvesAX=B
and stores it inX
The symbols :T
or :C
can be added as an extra argument to solve the transposed or the conjugate transposed system of equations, respectively.
Here is an example of solving a system of real equations with two right hand sides:
ps = PardisoSolver()
A = sparse(rand(10, 10))
B = rand(10, 2)
X = zeros(10, 2)
solve!(ps, X, A, B)
which happened to give the result
julia> X
10x2 Array{Float64,2}:
-0.487361 -0.715372
-0.644219 -3.38342
0.465575 4.4838
1.14448 -0.103854
2.00892 -7.04965
0.870507 1.7014
0.590723 -5.74338
-0.843841 -0.903796
-0.279381 7.24754
-1.17295 8.47922
Setting the number of threads
The number of threads to use are set in different ways for MKL PARDISO and PARDISO 5.0.
MKL PARDISO
set_nprocs!(ps, i) # Sets the number of threads to use
get_nprocs(ps) # Gets the number of threads being used
PARDISO 5.0
The number of threads are set at the creation of the PardisoSolver
by looking for the environment variable OMP_NUM_THREADS
. This can be done in Julia with for example ENV["OMP_NUM_THREADS"] = 2
. Note: OMP_NUM_THREADS
must be set before Pardiso
is loaded and can not be changed during runtime.
The number of threads used by a PardisoSolver
can be retrieved with get_nprocs(ps)
More advanced usage.
This section discusses some more advanced usage of Pardiso.jl
.
For terminology in this section please refer to the PARDISO 5.0 manual and the MKL PARDISO section.
After using functionality in this section, calls should no longer be made to the solve
functions but instead directly to the function
pardiso(ps, X, A, B)
This will ensure that the properties you set will not be overwritten.
If you want, you can use get_matrix(ps, A, T)
to return a matrix that is suitable to use with pardiso
depending on the matrix type that ps
has set. The parameter T
is a symbol representing if you will solve the normal, transposed or conjugated system. These are represented by :N, :T, :C)
respectively.
For ease of use, Pardiso.jl
provides enums for most options. These are not exported so has to either be explicitly imported or qualified with the module name first. It is possible to both use the enum as an input key to the options or the corresponding integer as given in the manuals.
Setting the matrix type
The matrix type can be explicitly set with set_matrixtype!(ps, key)
where the key has the following meaning:
enum | integer | Matrix type |
---|---|---|
REAL_SYM | 1 | real and structurally symmetric |
REAL_SYM_POSDEF | 2 | real and symmetric positive definite |
REAL_SYM_INDEF | -2 | real and symmetric indefinite |
COMPLEX_STRUCT_SYM | 3 | complex and structurally symmetric |
COMPLEX_HERM_POSDEF | 4 | complex and Hermitian positive definite |
COMPLEX_HERM_INDEF | -4 | complex and Hermitian indefinite |
COMPLEX_SYM | 6 | complex and symmetric |
REAL_NONSYM | 11 | real and nonsymmetric |
COMPLEX_NONSYM | 13 | complex and nonsymmetric |
The matrix type for a solver can be retrieved with get_matrixtype(ps)
.
Setting the solver (5.0 only)
PARDISO 5.0 supports direct and iterative solvers. The solver is set with set_solver!(ps, key)
where the key has the following meaning:
enum | integer | Solver |
---|---|---|
DIRECT_SOLVER | 0 | sparse direct solver |
ITERATIVE_SOLVER | 1 | multi-recursive iterative solver |
Setting the phase
Depending on the phase calls to solve
(and pardiso
which is mentioned later) does different things. The phase is set with set_phase!(ps, key)
where key has the meaning:
enum | integer | Solver Execution Steps |
---|---|---|
ANALYSIS | 11 | Analysis |
ANALYSIS_NUM_FACT | 12 | Analysis, numerical factorization |
ANALYSIS_NUM_FACT_SOLVE_REFINE | 13 | Analysis, numerical factorization, solve, iterative refinement |
NUM_FACT | 22 | Numerical factorization |
SELECTED_INVERSION | -22 | Selected Inversion |
NUM_FACT_SOLVE_REFINE | 23 | Numerical factorization, solve, iterative refinement |
SOLVE_ITERATIVE_REFINE | 33 | Solve, iterative refinement |
SOLVE_ITERATIVE_REFINE_ONLY_FORWARD | 331 | MKL only, like phase=33, but only forward substitution |
SOLVE_ITERATIVE_REFINE_ONLY_DIAG | 332 | MKL only, like phase=33, but only diagonal substitution (if available) |
SOLVE_ITERATIVE_REFINE_ONLY_BACKWARD | 333 | MKL only, like phase=33, but only backward substitution |
RELEASE_LU_MNUM | 0 | Release internal memory for L and U matrix number MNUM |
RELEASE_ALL | -1 | Release all internal memory for all matrices |
IPARM
and DPARM
explicitly
Setting Advanced users likely want to explicitly set and retrieve the IPARM
and DPARM
(5.0 only) parameters.
This can be done with the getters and setters:
get_iparm(ps, i) # Gets IPARM[i]
get_iparms(ps) # Gets IPARM
set_iparm!(ps, i, v) # Sets IPARM[i] = v
# 5.0 only
get_dparm(ps, i) # Gets DPARM[i]
get_dparms(ps) # Gets DPARM
set_dparm!(ps, i, v) # Sets DPARM[i] = v
To set the default values of the IPARM
and DPARM
call pardisoinit(ps)
. The default values depend on what solver and matrix type is set.
Setting message level
It is possible for Pardiso to print out timings and statistics when solving. This is done by set_msglvl!(ps, key)
where key has the meaning:
enum | integer | Solver |
---|---|---|
MESSAGE_LEVEL_OFF | 0 | no statistics printed |
MESSAGE_LEVEL_ON | 1 | statistics printed |
Matrix and vector checkers
PARDISO 5.0 comes with a few matrix and vector checkers to check the consistency and integrity of the input data. These can be called with the functions:
printstats(ps, A, B)
checkmatrix(ps, A)
checkvec(ps, B)
In MKL PARDISO this is instead done by setting IPARM[27]
to 1 before calling pardiso
.
MNUM, MAXFCT, PERM
These are set and retrieved with the functions
set_mnum!(ps, i)
get_mnum(ps)
set_maxfct!(ps, i)
get_maxfct(ps)
get_perm(ps)
set_perm!(ps, perm) # Perm is a Vector{Int}
Potential "gotchas"
- Julia uses CSC sparse matrices while PARDISO expects a CSR matrix. These can be seen as transposes of each other so to solve
AX = B
the transpose flag (IPARAM[12]
) should be set to 1. - For symmetric matrices, PARDISO needs to have the diagonal stored in the sparse structure even if the diagonal element happens to be 0. The manual recommends to add an
eps
to the diagonal when you suspect you might have 0 values diagonal elements that are not stored in the sparse structure. - Unless
IPARM[1] = 1
, all values inIPARM
will be ignored and default values are used. - When solving a symmetric matrix, Pardiso expects only the upper triangular part. Since Julia has CSC matrices this means you should pass in
tril(A)
to thepardiso
function. Usecheckmatrix
to see that you managed to get the matrix in a valid format.
Contributions
If you have suggestions or idea of improving this package, please file an issue or even better, create a PR!