Re: [q-lang-users] New stuff in cvs: multichar ops, views
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Re: [q-lang-users] New stuff in cvs: multichar ops, views
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From: <ed...@ri...> - 2007-06-29 12:05:55
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<html>=0D <BR> <BR> =0D <BLOCKQUOTE style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5p= x; BORDER-LEFT: #f5f5f5 2px solid; MARGIN-RIGHT: 0px">=0D <P>>Rob Hubbard wrote:<BR> <FONT color=3Dred>>> This is a rare occasion where I *strongly* disag= ree. The purpose of</FONT><BR> <FONT color=3Dred>>> (+:) is to form complex numbers syntactically, w= hen they are in some</FONT><BR> <FONT color=3Dred>>> sense 'atomic' or 'literal' semantically.</FONT>= <BR> <BR> >I see your point, but note that in common mathematical notation complex= <BR> >numbers aren't atomic either (unless you write them as pairs), so you<B= R> >face the same kind of problem.</P>=0D <P>>I have no problem with that if I read '1+:2*3+:4' as '1+i*2*3+i*4'.<= /P>=0D <P>In common mathematical notation, complex multiplication, for the rectang= ular form, is always written, at least as far as any of my complex&nbs= p;analysis books go, as</P>=0D <P>(a+bi)(c+di)</P>=0D <P>and simplified using the distributive law of multiplication over additio= n. </P>=0D <P>(ac-bd)+(ad+b)i </P>=0D <P>Hence, + is regular old real addition and multiplication is regular old = real multiplication. Albert is right about saying + in (a+bi) is not atomic= and neither is the multipliation. If multiplication were different, we wou= ldn't write bi as in b*i.</P>=0D <P>IIRC, Albert interpreted "a+:b" as "a+b*i" but somewhere else = I saw "+:" as a constructor for complex numbers. Wouldn't a constructo= r be defined as</P>=0D <P>a+bi =3D (a,b)</P>=0D <P>as in ordered pairs? I think I'm confused about what a "constructor" is.= I've been trying to look up constructor but I've only found "object orient= ed" stuff so far. Would anyone send back a definition?</P>=0D <P>Eddie</P></BLOCKQUOTE>=0D </html><BR>= |
