There is also
(**|)&.+.u
1 0 0
0 1 0
0 0 1
On 5/2/2012 6:11 AM, Bo Jacoby wrote:
> Hello J'ers
>
> Even if a complex number is actually real it may display nonzero imaginary
> part because of round-off errors. Adding and subtracting 1e6j1e6 removes the
> round-off error, but is there a better or more general solution?
>
> UM=.%:%~_1^]%~[:+:[:*/~i. NB. Unitary Matrix generator
>
> rd=.]&.(1e6j1e6&+) NB. round-off cleaner
>
> u=.n+/ .*+n=.UM 3 NB. unit matrix
>
> u NB. ugly display
> 1 _2.78e_17j_1.11e_16 1.11e_16j_2.22e_16
> _2.78e_17j1.11e_16 1 _2.78e_17j_1.11e_16
> 1.11e_16j2.22e_16 _2.78e_17j1.11e_16 1
>
> rd u NB. nice display
> 1 0 0
> 0 1 0
> 0 0 1
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>
--
Clifford A. Reiter
Lafayette College, Easton, PA 18042
http://webbox.lafayette.edu/~reiterc/
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