Error while calculating integral using Symbolic Math tool box

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Balaji 2014-4-30

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评论： Balaji 2014-5-2

I am trying to find integral of a function using Symbolic Math tool box. The integrand is as follows "expm(A*(t-tau))*B" here 't' is a parameter and 'tau' is the variable over which integration is to be performed. My problem contains 'A' as a 3*3 matrix and 'B' as 3*1 matrix. Answer is supposed to be a 3*1 matrix again. It successfully evaluated the integration for numerous possibilities of matrices 'A&B' but i got stuck with one combination which, when used, gives errors such as 1. No enough memory actual error is

"Error using mupadmex Error in MuPAD command: Out of memory.

Error in sym/int (line 124) rSym = mupadmex('symobj::intdef',f.s,x.s,a.s,b.s,options);Error using mupadmex Error in MuPAD command: Out of memory.

Error in sym/int (line 124) rSym = mupadmex('symobj::intdef',f.s,x.s,a.s,b.s,options);"

2. Internal Symbolic Math tool box error. Please restart MATLAB. The above errors are shown at two different instances i.e. they are not part of one error message. If anyone already encountered this error in some other problem and resolved, please help me. I can give matrices if this problem is the only one with that sort of an error (i don't guess so)

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Star Strider 2014-5-1

To use trapz effectively, you would have to take the Fourier transform of both A and B. If B is a constant matrix, this becomes something similar to a sampling convolution, where B exists only at one instant in time (t=tau), similar to a Dirac delta, if I remember my signal processing correctly.

Also, the x operator bothers me. Are you using simple matrix multiplication, or the cross-product? If the latter, the situation becomes significantly more difficult, and probably beyond my mathematical expertise.

Balaji 2014-5-2

Star Strider Thanks for your explanation. 'x' is for simple matrix multiplication. I forgot to mention. I will read about convolution and try to make my function more effective.

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