RosettaCodeData/Task/Runge-Kutta-method/J/runge-kutta-method-2.j
2015-02-20 09:02:09 -05:00

17 lines
543 B
Text

fy=: (%16) * [: *: 4 + *: NB. f(t,y)
fyp=: (* %:)/ NB. f'(t,y)
report_whole=: (10 * i. >:10)&{ NB. report at whole-numbered t values
report_err=: (, {: - [: fy {.)"1 NB. report errors
report_err report_whole fyp rk4 1 0 10 0.1
0 1 0
1 1.5625 _1.45722e_7
2 4 _9.19479e_7
3 10.5625 _2.90956e_6
4 25 _6.23491e_6
5 52.5625 _1.08197e_5
6 100 _1.65946e_5
7 175.562 _2.35177e_5
8 289 _3.15652e_5
9 451.562 _4.07232e_5
10 676 _5.09833e_5