Skip to content

Added ARK443 method #12

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Nov 6, 2024
Merged

Added ARK443 method #12

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
6fa426b
Added ARK443 method
brownbaerchen Nov 6, 2024
eaf0ce6
Fixed typo
brownbaerchen Nov 6, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
37 changes: 37 additions & 0 deletions qmat/qcoeff/butcher.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -855,6 +855,7 @@ class ARK222EDIRK(RK):
@property
def order(self): return 2


@registerRK
class ARK222ERK(ARK222EDIRK):
"""
Expand All @@ -865,3 +866,39 @@ class ARK222ERK(ARK222EDIRK):
[ARK222EDIRK.gamma, 0 , 0],
[ARK222EDIRK.delta, 1-ARK222EDIRK.delta, 0]])
b = A[-1, :]


@registerRK
class ARK443ESDIRK(RK):
"""
3rd-order 4-stage ESDIRK scheme [Ascher 1997 sec 2.8]
Use as implicit part for ARK scheme in combination with ARK443ERK.
"""

c = np.array([0, 1/2, 2/3, 1/2, 1])

A = np.array([[0, 0 , 0 , 0 , 0 ],
[0, 1/2, 0 , 0 , 0 ],
[0, 1/6, 1/2, 0 , 0 ],
[0, -1/2, 1/2, 1/2, 0 ],
[0, 3/2, -3/2, 1/2, 1/2]])


b = A[-1, :]

@property
def order(self): return 3


@registerRK
class ARK443ERK(ARK443ESDIRK):
"""
3rd-order 4-stage ERK scheme [Ascher 1997 sec 2.8]
Use as explicit part for ARK scheme in combination with ARK443ESDIRK.
"""
A = np.array([[ 0 , 0 , 0 , 0 , 0],
[ 1/2 , 0 , 0 , 0 , 0],
[11/18, 1/18, 0 , 0 , 0],
[ 5/6 , -5/6 , 1/2, 0 , 0],
[ 1/4 , 7/4 , 3/4, -7/4, 0]])
b = A[-1, :]
Loading