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Re: complex arithmetic [message #1922 is a reply to message #1921]

Wed, 06 April 1994 06:17

landers
Messages: 45
Registered: May 1993

Member

First, let me agree that there's no reason that this kind of thing should not be
supported. But...

Of course, you could do:

WAVE> x = complex( 0.,1.)
WAVE> print, exp( 3. * alog( x ) )
( 1.19249e-08, -1.00000)

Just a bit of residual error there in the real part....
This kind of technique will handle complex exponents, too.

It would be pretty easy to write a "pow.pro" around this - test for combo
of complex arg / non-int expo, and do the log thing.

(disclaimers - I use PV-WAVE - I tested this only lightly - YMMV - etc.)

function pow, arg, expo

on_error,2

if n_params() ne 2 then message, 'Usage: result = POW( argument, exponent )'

; argument sizes...
sa = size(arg)
se = size(expo)

; argument types...
ta = sa(sa(0)+1)
te = se(se(0)+1)

; test for structs/strings
if ta ge 7 or te ge 7 then message, 'Illegal data type.'

; check arg,expo combos - use hard way if complex^(float|double|complex)
; or anything^complex
if ( ta eq 6 and te ge 4) or te eq 6 then begin

ans = exp( expo * alog( arg ) )

endif else begin

ans = arg^expo

endelse

return, ans
end

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[Message index]

		Re: complex arithmetic By: isaacman on Wed, 06 April 1994 08:37
		Re: complex arithmetic By: salchegg on Wed, 06 April 1994 07:36
		Re: complex arithmetic By: thompson on Wed, 06 April 1994 07:23
		Re: complex arithmetic By: jjp on Wed, 06 April 1994 06:23
		Re: complex arithmetic By: landers on Wed, 06 April 1994 06:17
		Re: complex arithmetic By: stl on Tue, 05 April 1994 23:49

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