32 lines
936 B
Factor
32 lines
936 B
Factor
IN: math-contrib
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USING: kernel sequences errors namespaces math vectors errors prettyprint io tools ;
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: setup-range ( from to -- frange )
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step-size get swap <frange> ;
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: integrate-rect ( from to f -- x )
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>r setup-range dup decrement-length r>
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[ step-size get * ] append map sum ;
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: integrate-trap ( from to f -- x )
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>r setup-range r>
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map dup 1 tail >r >vector dup pop drop r>
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[ + 2 / step-size get * ] 2map sum ;
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SYMBOL: num-steps 180 num-steps set ! simpsons
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: setup-simpson-range ( from to -- frange )
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[ swap - num-steps get /f ] 2keep swapd <frange> ;
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: generate-simpson-weights ( seq -- seq )
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length 2 / V{ 1 4 } clone swap 2 -
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[ { 2 4 } append ] times { 1 } append ;
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: integrate-simpson ( from to f -- x )
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>r setup-simpson-range r> dupd map dup generate-simpson-weights
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[ * ] 2map sum swap [ third ] keep first - 6 / * ;
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: quadrature ( from to f -- x )
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integrate-simpson ;
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