CG LINEAR SOLVER = Conjugate Gradient More...
Functions/Subroutines | |
| subroutine, public | cg (x, iter, res, b, A, tol, itmax, verb) |
| Conjugate gradient (no preconditioning) More... | |
| subroutine, public | pcg (x, iter, res, b, A, pc, tol, itmax, verb) |
| Preconditioned conjugate gradient. More... | |
Detailed Description
CG LINEAR SOLVER = Conjugate Gradient
- cg : conjugate gradient
- pcg: preconditionned conjugate gradient
Source = Youssef SAAD, Iterative methods for sparse linear system
https://www-users.cs.umn.edu/~saad/IterMethBook_2ndEd.pdf
Function/Subroutine Documentation
◆ cg()
| subroutine, public cg_mod::cg | ( | real(rp), dimension(:), intent(inout) | x, |
| integer, intent(out) | iter, | ||
| real(rp), intent(out) | res, | ||
| real(rp), dimension(:), intent(in) | b, | ||
| procedure(rntorn) | A, | ||
| real(rp), intent(in) | tol, | ||
| integer, intent(in) | itmax, | ||
| integer, intent(in) | verb | ||
| ) |
Conjugate gradient (no preconditioning)
for the linear system \( Ax = b\)
INPUT/OUTPUT :
- x = initial guess / solution
OUTPUT :
- res = final residual
- iter = number of performed iterations
- iter = -1 = resolution failure
INPUT :
- b = RHS
- A = \( A~:~~~x \mapsto A x \) matrix/vector product (procedural)
- tol = tolerance
- itMax = maximal iteration-number
- verb = verbosity
Definition at line 60 of file cg_mod.f90.
Here is the call graph for this function:
◆ pcg()
| subroutine, public cg_mod::pcg | ( | real(rp), dimension(:), intent(inout) | x, |
| integer, intent(out) | iter, | ||
| real(rp), intent(out) | res, | ||
| real(rp), dimension(:), intent(in) | b, | ||
| procedure(rntorn) | A, | ||
| procedure(rntorn) | pc, | ||
| real(rp), intent(in) | tol, | ||
| integer, intent(in) | itmax, | ||
| integer, intent(in) | verb | ||
| ) |
Preconditioned conjugate gradient.
for the linear system \( Ax = b\)
and for a preconditionner \( P \)
INPUT/OUTPUT :
- x = initial guess / solution
OUTPUT :
- res = final residual
- iter = number of performed iterations
- iter = -1 = resolution failure
INPUT :
- b = RHS
- A = \( A~:~~~x \mapsto A x \) matrix/vector product (procedural)
- pc = \( pc~:~~~x \mapsto P^{-1} x \) preconditionner/vector product (procedural)
- tol = tolerance
- itMax = maximal iteration-number
- verb = verbosity
Definition at line 155 of file cg_mod.f90.
Here is the call graph for this function:
