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  • Category: Mathematics
  • Founded: May 21, 2001
  • Language: English
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tratios and yantras   Message List  
Reply Message #10408 of 20696 |
Re: tratios and yantras

--- In tuning-math@yahoogroups.com, "Paul Erlich" <perlich@a...>
wrote:

> 7-limit Blackwood 243:252:256 lcm 435,456

I just found this for Blackwood:

189:192:196 lcm 84,672

I guess "by inspection" doesn't cut it.

I'll have to do this systematically.

Here's my Matlab program to convert from tratios to wedgies:

function out=trat2wedg(a1,a2,a3);
j=factor(a1);
a12=sum(j==2);
a13=sum(j==3);
a15=sum(j==5);
a17=sum(j==7);
j=factor(a2);
a22=sum(j==2);
a23=sum(j==3);
a25=sum(j==5);
a27=sum(j==7);
j=factor(a3);
a32=sum(j==2);
a33=sum(j==3);
a35=sum(j==5);
a37=sum(j==7);
w=([det([a22-a12 a23-a13;a22-a32 a23-a33]) det([a22-a12 a25-a15;a22-
a32 a25-a35]) det([a22-a12 a27-a17;a22-a32 a27-a37]) det([a23-a13 a25-
a15;a23-a33 a25-a35]) det([a23-a13 a27-a17;a23-a33 a27-a37]) det([a25-
a15 a27-a17;a25-a35 a27-a37])]);
g=gcd(w(1),gcd(w(2),gcd(w(3),gcd(w(4),gcd(w(5),w(6))))));
out=w/g;


> Dominant Sevenths 245:252:256 lcm 564,480
> 7-limit Diminished 343:350:360 lcm 617,400
> Pajara 441:448:450 lcm 705,600
> Semifourths 240:243:245 lcm 952,560
> Tripletone 125:126:128 lcm 1,008,000
> Injera 392:400:405 lcm 1,587,600
> meantone 1120:1125:1134 lcm 2,268,000
> 7-limit Augmented:
> 1125:1152:1176 lcm 7,056,000
> BUT ALSO
> 1568:1575:1620 lcm 3,175,200
> (any simpler tratio?)
> OldKleismic 1000:1008:1029 lcm 6,174,000
> Catler -- same as 12-equal -- 625:648:640 lcm 6,480,000
> Negri 672:675:686 lcm 7,408,800
> semisixths 3375:3402:3430 lcm 20,837,250
> Superpythagorean 1701:1715:1728 lcm 26,671,680
> magic 6048:6075:6125 lcm 47,628,000
> miracle 7168:7200:7203 lcm 553,190,400
> orwell 12005:12096:12150 lcm 933,508,800
> (septimal) schismic 27783:28000:28125 lcm 2,778,300,000
> ennealimmal 419904:420000:420175 lcm 4,410,829,080,000
>
> What's bigger -- the lcm of ennealimmal or the national debt?




Thu May 13, 2004 10:19 am

paulerlich
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Message #10408 of 20696 |
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I took all the 7-limit integers less than 2^20 (recall this is a yantra when reduced to an octave) and found the smallest instance of three successive 7-limit...
Gene Ward Smith
genewardsmith Offline Send Email
Apr 27, 2004
8:18 am

I'm adding LCMs below, though i still don't know if the numbers and/or LCMs are smallest possible. It's interesting that the LCMs seem to give a much better...
Paul Erlich
paulerlich Offline Send Email
May 13, 2004
5:23 am

... the ... the ... get ... temperament, ... . . . on Sept. 30th, 1993?...
Paul Erlich
paulerlich Offline Send Email
May 13, 2004
5:25 am

... I just found this for Blackwood: 189:192:196 lcm 84,672 I guess "by inspection" doesn't cut it. I'll have to do this systematically. Here's my Matlab...
Paul Erlich
paulerlich Offline Send Email
May 13, 2004
10:20 am

... But now I must sleep . . ....
Paul Erlich
paulerlich Offline Send Email
May 13, 2004
10:21 am

... I did something a little more straightforward. I calculated the wedgie for every triplet of consecutive 7-limit integers, through 99999. Then I just looked...
Paul Erlich
paulerlich Offline Send Email
May 13, 2004
10:43 pm

hi Gene and Paul, definitions of tratio and yantra, please. thanks. -monz...
monz
joemonz Offline Send Email
May 15, 2004
5:57 pm

... Hi Monz, Gene defined yantra here: http://groups.yahoo.com/group/tuning-math/message/10095 It's just the first N integers with no prime factors above P,...
Paul Erlich
paulerlich Offline Send Email
May 19, 2004
9:20 pm

hi Paul, ... thanks. Ernest McClain's definition of yantra (which i believe was Gene's source) always includes a terminating maximum value below which all the...
monz
joemonz Offline Send Email
May 21, 2004
9:14 am

... I think my definition is preferable, as it gives a 1-1 mapping. In any case, they are equivalent....
Gene Ward Smith
genewardsmith Offline Send Email
May 21, 2004
10:47 pm
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