Exporting results from NDSolve?

Questions
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1

Hi Guys

If I have “s” which pertains to the results from NDSolve, how can I export the results to excel?
I require the numerical values of “x” and the values for “t”

s = NDSolveValue[sys, x, {t, 0, tf}]

Furthermore I am not sure how Mathematica deals with it’s time steps, I would assume that the time steps are regular as produced by the ODE solvers in Matlab, however if the time steps are irregular, how can I get raw data with a regular time step?

Thus far I have figured out the that the raw data can be attained using the below

{s["Grid"], s["ValuesOnGrid"]}
2

Is your difficulty the export itself, or is it getting a table of values?

In your example, the value of s should be an InterpolatingFunction. That’s just like any other function that can be applied to arguments. So, if you wanted a table of values for your range {0, tf}, then you could just evaluate s for values in that range spaced at whatever intervals you want. Like this (let’s say tf is 10 and you want your spacing to be .5):

Table[{x, s[x]}, {x, 0, 10, .5}]

Or if you want to specify the number of samples (e.g. 35) instead of spacing:

Array[{#, s[#]} &, 35, {0, 10}]

If your difficulty is the export, then you need to decide the appropriate format. I assume you’ll want CSV, so just use “CSV” as your format when you use Export (see Export: Write data to a specified file format—Wolfram Documentation)

3

Thank you kindly.