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Error, (in ...) input system must be an ODE system, got independent variables ...

 

Description

Examples

See Also

Description

The error message occurs only when there are unknown functions operating on different independent variables in the same problem.

Examples

Example 1
 gy entered instead of gx

dsolvedifffx,x=gy,numeric;

Error, (in dsolve/numeric/process_input) input system must be an ODE system, got independent variables {x, y}

Example 2
Two separate ODE problems entered as one problem, each using a different independent variable.

 dsolvedifffx,x=fx,diffgy,y=gy,f0=1,g0=1,numeric;

Error, (in dsolve/numeric/process_input) input system must be an ODE system, got independent variables {x, y}

Solution
Split the problem into 2 parts:

dsolvedifffx,x=fx,f0=1,numeric,dsolvediffgy,y=gy,g0=1,numeric; 

procx_rkf45...end proc,procx_rkf45...end proc

(2.1)

Or to fix 'g' using:

dsolvedifffx,x=fx,diffgx,x=gx,f0=1,g0=1,numeric; 

procx_rkf45...end proc

(2.2)

See Also

diff, dsolve