factor/extra/math/numerical-integration/numerical-integration.factor

19 lines
532 B
Factor

USING: arrays kernel sequences namespaces math math.ranges
math.vectors vectors ;
IN: math.numerical-integration
SYMBOL: num-steps 180 num-steps set-global
: setup-simpson-range ( from to -- frange )
2dup swap - num-steps get / <range> ;
: generate-simpson-weights ( seq -- seq )
[
{ 1 4 } % length 2 / 2 - { 2 4 } <repetition> concat % 1 ,
] { } make ;
: integrate-simpson ( from to f -- x )
>r setup-simpson-range r>
dupd map dup generate-simpson-weights
v. swap [ third ] keep first - 6 / * ;