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{{libheader|math/calculus}} |
{{libheader|math/calculus}} |
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In earlier versions D. can be used instead of pderiv |
In earlier versions without calculus library, D. can be used instead of pderiv |
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<syntaxhighlight lang="J"> |
<syntaxhighlight lang="J"> |
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| ⚫ | |||
| ⚫ | |||
NB. In earlier versions D. can be used instead of pderivw |
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| ⚫ | |||
NB. ========== Precision |
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| ⚫ | |||
ps=: 9!:11 |
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ps 18 |
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NB. ========== Function definition |
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func=: monad define |
func=: monad define |
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| Line 23: | Line 18: | ||
) |
) |
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NB. ========== Gradient descent |
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shortygd =: monad define |
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go=.y |
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learn=: 0.03 |
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go=. go - 0.03 * func pderiv 1 ] go NB. use D. instead of pderiv for earlier versions |
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gold=: 1 1 |
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precision=: 1e_10 |
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flagg=:0 |
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attempts =: 1000 |
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i=:0 |
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go=: 0.1 _1 |
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while. (i < attempts) & !(flagg=0) do. |
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go=: go-learn * func pderiv 1 ] go |
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i=: >: i |
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if. (precision > | (func go) - (func gold)) do. |
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flagg=:1 |
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end. |
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gold=: go |
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smoutput i,go |
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end. |
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smoutput 'x';({.go);'y';({:go);'f(x,y)';func go |
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) |
) |
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shortygd ^:_ go |
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</syntaxhighlight> |
</syntaxhighlight> |
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{{out}} |
{{out}} |
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<pre> |
<pre> |
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0.107626780140768125 _1.22325973233483509 |
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NB. 1 0.181030990251029783 _1.17878944691407384 |
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NB. 2 0.106526139628704192 _1.19653062777180708 |
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NB. 3 0.114463555353394503 _1.21817798934176125 |
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NB. 4 0.107500175480679167 _1.22061411764084937 |
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NB. 5 0.108281552776878703 _1.22275948119432343 |
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NB. 6 0.107616591357617614 _1.22300417912290982 |
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NB. 7 0.107689377135022829 _1.2232109060917864 |
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NB. 8 0.107626033138308236 _1.22323510540100955 |
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NB. 9 0.107632763421305816 _1.2232549721759014 |
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NB. 10 0.107626730913479213 _1.22325735959949355 |
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NB. |
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NB. ┌─┬────────────────────┬─┬────────────────────┬──────┬─────────────────────┐ |
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NB. │x│0.107626730913479213│y│_1.22325735959949355│f(x,y)│_0.750063420544188286│ |
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NB. └─┴────────────────────┴─┴────────────────────┴──────┴─────────────────────┘ |
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</pre> |
</pre> |
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Revision as of 15:19, 15 January 2023
J
In earlier versions without calculus library, D. can be used instead of pderiv
load 'math/calculus'
coinsert 'jcalculus'
ps=: 9!:11
ps 18
func=: monad define
'xp yp' =: y
((1-xp)*(1-xp) * ] ^-(yp)^2) + yp*(yp+2)* ] ^ _2 * xp^2
)
shortygd =: monad define
go=.y
go=. go - 0.03 * func pderiv 1 ] go NB. use D. instead of pderiv for earlier versions
)
shortygd ^:_ go
- Output:
0.107626780140768125 _1.22325973233483509