# Some iterative solvers in LinearSolve ignore the initial conditions
**URL:** https://discourse.julialang.org/t/some-iterative-solvers-in-linearsolve-ignore-the-initial-conditions/118903
**Category:** General Usage
**Tags:** linearalgebra, linearsolve
**Created:** [September 1, 2024, 8:50am UTC](https://discourse.julialang.org/t/some-iterative-solvers-in-linearsolve-ignore-the-initial-conditions/118903 "2024-09-01T08:50:34Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@c\_sell](https://discourse.julialang.org/u/c_sell)
#### Post date: [September 1, 2024, 8:50am UTC](https://discourse.julialang.org/t/some-iterative-solvers-in-linearsolve-ignore-the-initial-conditions/118903/1 "2024-09-01T08:50:34Z")
Hello,
I think I might be doing something wrong, but it seems that none of the Krylov methods in `LinearSolve` are using the initial guess I provide. (In the small example below, the initial guess is the true solution.)
```julia
import LinearSolve as LS
using SparseArrays
using Random
rng = Random.MersenneTwister(123)
_A = sprand(rng,10,10,0.3)
A = _A * _A'
rhs = rand(rng,10)
# get an "initial guess"
prob1 = LS.LinearProblem(A,rhs)
u0 = LS.solve(prob1,LS.KrylovJL_GMRES())
residual = A * u0 - rhs
# use the initial guess
prob2 = LS.LinearProblem(A,rhs;u0 = u0)
LS.solve(prob2,LS.KrylovJL_GMRES(),verbose = true)
```
Thanks for your help
---
### Author:  [@Oscar\_Smith](https://discourse.julialang.org/u/Oscar_Smith)
#### Post date: [September 1, 2024, 2:44pm UTC](https://discourse.julialang.org/t/some-iterative-solvers-in-linearsolve-ignore-the-initial-conditions/118903/2 "2024-09-01T14:44:56Z")
Sounds like a bug. Would you mind filing an issue to make it easy for us to track? (Also @ChrisRackauckas this definitely could explain some of the non-determinism I’ve been running into).
---
### Author:  [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)
#### Post date: [September 1, 2024, 2:57pm UTC](https://discourse.julialang.org/t/some-iterative-solvers-in-linearsolve-ignore-the-initial-conditions/118903/3 "2024-09-01T14:57:32Z")
No, this is not a bug. It’s a property of GMRES. We currently zero the values because of the extensive literature on this, see [Better initial guesses for reinitialized iterative solvers · Issue #70 · SciML/LinearSolve.jl · GitHub](https://github.com/SciML/LinearSolve.jl/issues/70). There are ways to do non-zero guesses, but rand like this is not necessarily convergent so it’s not a good idea to just accept it. We’d have to renormalize it or something, again see the papers linked in the issue.
> [@Oscar\_Smith](#):
>
> (Also @ChrisRackauckas this definitely could explain some of the non-determinism I’ve been running into).
No, 0 is deterministic.