--- gsl-1.2/ode-initval/rk8pd.c~ Mon Nov 19 22:39:32 2001 +++ gsl-1.2/ode-initval/rk8pd.c Wed Oct 9 09:49:26 2002 @@ -17,7 +17,12 @@ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ -/* Runge-Kutta 8(9), Prince-Dormand */ +/* Runge-Kutta 8(7), Prince-Dormand + * The original article is : + * High order embedded Runge-Kutta formulae + * P.J. Prince and J.R. Dormand + * Journal of Computational and Applied Mathematics, volume 7, no. 1, 1981 + */ /* Author: G. Jungman */ @@ -80,14 +85,21 @@ static const double b4[] = { 1.0 / 32.0, 0.0, 3.0 / 32.0 }; static const double b5[] = { 5.0 / 16.0, 0.0, -75.0 / 64.0, 75.0 / 64.0 }; static const double b6[] = { 3.0 / 80.0, 0.0, 0.0, 3.0 / 16.0, 3.0 / 20.0 }; + +/* the b7[0] and b7[3] coefficients were corrected by Luc Maisonobe + * since the approximation given in the original article seemed to be + * wrong, because the sum b7[0]+b7[1]+ ... +b7[5] was not equal to + * ah[5] as it should be. + */ static const double b7[] = { - 29443841.0 / 614563906.0, + 215595617.0 / 4500000000.0, /* was 29443841/614563906 in the article */ 0.0, 0.0, - 77736538.0 / 692538347.0, + 202047683.0 / 1800000000.0, /* was 77736538/692538347 in the article */ -28693883.0 / 1125000000.0, 23124283.0 / 1800000000.0 }; + static const double b8[] = { 16016141.0 / 946692911.0, 0.0,