How to solve nested differential equations in R?
I would like to solve a couple of nested differential equations in R. Suppose that x'=x+a with x(T) given and y'= y + x+b with y(0) given, where a and b are constant. The first equation is independent from the second and it can be solved with deSolve by reversing time, since it has a terminal condition. The second equation needs to be solved using the solution of the first equation and with time moving forward since it has an initial condition. Is there any way to store the value of the solution for x in such a way that can be used for solving the y equation?
I tried to use X <- out[, "X"], where out is the output for the function solving for the x equation, and plug X into the function solving for y, but I get the following message:
The number of derivatives returned by func() must equal the length of the initial conditions vector.
I understand the nature of the problem, but I do not know to get rid of this.
r differential-equations
asked Nov 12 '18 at 22:43
user3026610user3026610
124
add a comment |
I would like to solve a couple of nested differential equations in R. Suppose that x'=x+a with x(T) given and y'= y + x+b with y(0) given, where a and b are constant. The first equation is independent from the second and it can be solved with deSolve by reversing time, since it has a terminal condition. The second equation needs to be solved using the solution of the first equation and with time moving forward since it has an initial condition. Is there any way to store the value of the solution for x in such a way that can be used for solving the y equation?
I tried to use X <- out[, "X"], where out is the output for the function solving for the x equation, and plug X into the function solving for y, but I get the following message:
The number of derivatives returned by func() must equal the length of the initial conditions vector.
I understand the nature of the problem, but I do not know to get rid of this.
r differential-equations
asked Nov 12 '18 at 22:43
user3026610user3026610
124
add a comment |
I would like to solve a couple of nested differential equations in R. Suppose that x'=x+a with x(T) given and y'= y + x+b with y(0) given, where a and b are constant. The first equation is independent from the second and it can be solved with deSolve by reversing time, since it has a terminal condition. The second equation needs to be solved using the solution of the first equation and with time moving forward since it has an initial condition. Is there any way to store the value of the solution for x in such a way that can be used for solving the y equation?
I tried to use X <- out[, "X"], where out is the output for the function solving for the x equation, and plug X into the function solving for y, but I get the following message:
The number of derivatives returned by func() must equal the length of the initial conditions vector.
I understand the nature of the problem, but I do not know to get rid of this.
r differential-equations
asked Nov 12 '18 at 22:43
user3026610user3026610
124
I would like to solve a couple of nested differential equations in R. Suppose that x'=x+a with x(T) given and y'= y + x+b with y(0) given, where a and b are constant. The first equation is independent from the second and it can be solved with deSolve by reversing time, since it has a terminal condition. The second equation needs to be solved using the solution of the first equation and with time moving forward since it has an initial condition. Is there any way to store the value of the solution for x in such a way that can be used for solving the y equation?
I tried to use X <- out[, "X"], where out is the output for the function solving for the x equation, and plug X into the function solving for y, but I get the following message:
The number of derivatives returned by func() must equal the length of the initial conditions vector.
I understand the nature of the problem, but I do not know to get rid of this.
r differential-equations
r differential-equations
asked Nov 12 '18 at 22:43
user3026610user3026610
124
asked Nov 12 '18 at 22:43
user3026610user3026610
124
asked Nov 12 '18 at 22:43
user3026610user3026610
124
asked Nov 12 '18 at 22:43
user3026610user3026610
124
asked Nov 12 '18 at 22:43
user3026610user3026610
124
124
add a comment |
add a comment |
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