Unable to sort symbolic variables in matlab

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There is a an issue in one section of my code. Let I have this symbolic equation. When i use the coeffs function like this it gives me the right coefficients and variables.
eq=(10219275*P10_10)/2097152 - P10_9/10 - P9_10/10
[a,b]=coeffs(eq);
a =
[ -1/10, 10219275/2097152, -1/10]
b =
[ P10_9, P10_10, P9_10]
but i want it to return me the variables and its coefficients in this order. How can i go about this rearrangement.
b =
[ P9_10, P10_9, P10_10]
Please help me.

Risposta accettata

Star Strider
Star Strider il 24 Feb 2016
You can tell coeffs the order in which you want the coefficients returned:
syms P10_9 P10_10 P9_10
eq=(10219275*P10_10)/2097152 - P10_9/10 - P9_10/10
[a,b]=coeffs(eq, [P9_10, P10_9, P10_10])
a =
[ -1/10, -1/10, 10219275/2097152]
b =
[ P9_10, P10_9, P10_10]
  4 Commenti
Walter Roberson
Walter Roberson il 24 Feb 2016
Sort order is first by the number after 'P' and before the '_', and secondarily by the number after the '_'
Aftab Ahmed Khan
Aftab Ahmed Khan il 24 Feb 2016
Well, i have managed to do it in another way found on the internet. Thanks once again.

Accedi per commentare.

Più risposte (1)

Walter Roberson
Walter Roberson il 24 Feb 2016
Use http://www.mathworks.com/matlabcentral/fileexchange/10959-sort-nat--natural-order-sort a "natural sort" on the output of symvar() to get the order you want to do the sorting in, and then pass the sorted result as the second parameter of coeffs

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