ivp.ab solver

[Jewel Bright <jwlbright@yahoo.com>]

Dear S-plusers:

Does anybody have any experience with the S-PLUS differential equation solver 'ivp.ab'. I tried to use it following the instructions in the help file but in vain. The example is very murky. It does not even say what diff equation is being solved. Seems to me that the syntax in example is wrong. I think that such an important thing as diff equation, which is central to all the mathematics, deserve greater attention of S-PLUS developers. Please help. I think that just an example to follow would be OK with me. If nobody has a ready to use example, then maybe somebody can help me with the following.

 

I have a system of equations:

 

dx/dt=exp(a11*x+a12*y+a13*z)-exp(b11*x+b12*y+b13*z)

dy/dt=exp(a21*x+a22*y+a23*z)-exp(b21*x+b22*y+b23*z)

dz/dt=exp(a31*x+a32*y+a33*z)-exp(b31*x+b32*y+b33*z)

 

and some kind of initial conditions, say

 

x(0)=0; y(0)=-1; z(0)=1

 

Please, help to formulate the problem using the ivp.ab

 

Many thanks in advance

 

Jewel Bright

 

 

 

 

 

 

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