Error, (in ...) input system must be an ODE system, got independent variables ...
Description
Examples
The error message occurs only when there are unknown functions operating on different independent variables in the same problem.
Example 1 yx entered instead of yt
dsolvediffxt,t=yx,diffyt,t=−xt,x0=1,y0=0,numeric;
Error, (in dsolve/numeric/process_input) input system must be an ODE system, got independent variables {t, x}
Solution
dsolvediffxt,t=yt,diffyt,t=−xt,x0=1,y0=0, numeric;
procx_rkf45...end proc
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
Or to fix 'g' using:
dsolvedifffx,x=fx,diffgx,x=−gx,f0=1,g0=−1,numeric;
See Also
diff
dsolve
dsolve/numeric
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