change rtol and atol defaults

Author: jalvesz

doc/specs/stdlib_linalg_iterative_solvers.md

@@ -152,7 +152,7 @@ Subroutine
 
 `di` (optional): 1-D mask array of type `logical(int8)` defining the degrees of freedom subject to dirichlet boundary conditions. The actual boundary conditions values should be stored in the `b` load array. This argument is `intent(in)`.
 
-`rtol` and `atol` (optional): scalars of type `real(<kind>)` specifying the convergence test. For convergence, the following criterion is used \( || b - Ax ||^2 <= max(rtol^2 * || b ||^2 , atol^2 ) \). Defaults values are `rtol=1.e-4` and `atol=0`. These arguments are `intent(in)`.
+`rtol` and `atol` (optional): scalars of type `real(<kind>)` specifying the convergence test. For convergence, the following criterion is used \( || b - Ax ||^2 <= max(rtol^2 * || b ||^2 , atol^2 ) \). Defaults values are `rtol=1.e-5` and `atol=epsilon(1._<kind>)`. These arguments are `intent(in)`.
 
 `maxiter` (optional): scalar of type `integer` defining the maximum allowed number of iterations. If no value is given, a default of `N` is set, where `N = size(b)`. This argument is `intent(in)`.
 
@@ -234,7 +234,7 @@ Subroutine
 
 `di` (optional): 1-D mask array of type `logical(int8)` defining the degrees of freedom subject to dirichlet boundary conditions. The actual boundary conditions values should be stored in the `b` load array. This argument is `intent(in)`.
 
-`rtol` and `atol` (optional): scalars of type `real(<kind>)` specifying the convergence test. For convergence, the following criterion is used \( || b - Ax ||^2 <= max(rtol^2 * || b ||^2 , atol^2 ) \). Defaults values are `rtol=1.e-4` and `atol=0`. These arguments are `intent(in)`.
+`rtol` and `atol` (optional): scalars of type `real(<kind>)` specifying the convergence test. For convergence, the following criterion is used \( || b - Ax ||^2 <= max(rtol^2 * || b ||^2 , atol^2 ) \). Defaults values are `rtol=1.e-5` and `atol=epsilon(1._<kind>)`. These arguments are `intent(in)`.
 
 `maxiter` (optional): scalar of type `integer` defining the maximum allowed number of iterations. If no value is given, a default of `N` is set, where `N = size(b)`. This argument is `intent(in)`.
 

src/stdlib_linalg_iterative_solvers_cg.fypp

@@ -91,8 +91,8 @@ contains
         n = size(b)
         maxiter_ = optval(x=maxiter, default=n)
         restart_ = optval(x=restart, default=.true.)
-        rtol_    = optval(x=rtol,    default=1.e-4_${s}$)
-        atol_    = optval(x=atol,    default=zero_${s}$)
+        rtol_    = optval(x=rtol,    default=1.e-5_${s}$)
+        atol_    = optval(x=atol,    default=epsilon(one_${s}$))
 
         !-------------------------
         ! internal memory setup

src/stdlib_linalg_iterative_solvers_pcg.fypp

@@ -117,8 +117,8 @@ contains
         n = size(b)
         maxiter_ = optval(x=maxiter, default=n)
         restart_ = optval(x=restart, default=.true.)
-        rtol_    = optval(x=rtol,    default=1.e-4_${s}$)
-        atol_    = optval(x=atol,    default=zero_${s}$)
+        rtol_    = optval(x=rtol,    default=1.e-5_${s}$)
+        atol_    = optval(x=atol,    default=epsilon(one_${s}$))
         precond_ = optval(x=precond, default=pc_none)
         !-------------------------
         ! internal memory setup