topic Re: Symbolic calc is very slow (MC15) in Mathcad

Symbolic calc is very slow (MC15)

ifomenko — Tue, 11 Feb 2020 16:47:18 GMT

Hi, I`m trying to get tangent stiffness matrix of 6 nodes triangular finite element. Beginning part of code contains symbolic calculation and very simple operations such as getting one element of vector or transpose are very very slow. So I can`t to continue.Thanks in advance for any advice. File is attached.

Re: Symbolic calc is very slow (MC15)

-MFra- — Tue, 11 Feb 2020 17:34:53 GMT

Hi.

It is not slow for me.

At the beginning of the file - it is better to define the variables and constants in any way - and then reset them all - as shown below -

Re: Symbolic calc is very slow (MC15)

ifomenko — Tue, 11 Feb 2020 17:54:52 GMT

It takes 20 sec to recalculate worksheet for N.nd=6

and what`s about you?

Re: Symbolic calc is very slow (MC15)

Werner_E — Tue, 11 Feb 2020 18:55:44 GMT

You are calling B N.nd times just to pick out one of the six results and transpose it. Its sure more efficient to call B.n just once and work on the result.

This modification should do the job approx. N.nd times faster 😉

Re: Symbolic calc is very slow (MC15)

ifomenko — Tue, 11 Feb 2020 19:09:49 GMT

Many thanks my dear Werner, I`m so inattentive, I`m sorry.

Re: Symbolic calc is very slow (MC15)

ifomenko — Tue, 25 Feb 2020 18:29:58 GMT

Ok, but what if I have such situation

EDIT: How to prevent lazy evaluation and calculate all B.(n) before this procedure?