[Amforth-devel] Float testing - simple integration

[pito <pi...@vo...>]

Hi, here is a very simple integration (no special method applied)
for testing f+ and f*.
It integrates y=x^3 from A to B. Currently A=-B (e.g. -1 to +1) thus
the result shall be zero. Still thinking on N in the loop (:-)).
Pito

-------------------------
marker -testadd

\ very simple integration to test float add, sub

\ needs float constants

\ INTEGRAL from A to B of the function Y=X^3

\ A=-B, So the result shall be 0

-1 s>f fconstant _-1
0 s>f fconstant _0

\ FROM A TO B

-1 s>f fconstant A
A _-1 f* fconstant B

300 constant N

B A f- N s>f f/ fconstant delta

fvariable INTG
fvariable X
fvariable Y
variable NLoop

: p6 _1e6 f* f>d d. ." .1e-6 " ;
: p3 _1e3 f* f>d d. ." .1e-3 " ;

: Y=X^3 fdup fdup f* f* ;

: Y=X^2 fdup f* ;

: print_INTG INTG f@ p3 ; 

: INTEGRAL 
A X f!
_0 INTG f!
N 1 + NLoop !

NLoop @ 0 do

X f@ Y=X^3 Y f!

\ print X, Y
cr cr X f@ ." X=" p6 cr Y f@ ." Y=" p3 

Y f@ INTG f@ f+ INTG f! 
X f@ delta f+ X f!

\ print
cr INTG f@ ." INTG=" p3

loop

\ print
cr	cr ." RESULT=" print_INTG
;

-----------------
Ex:
.....
X=1000004 .1e-6 
Y=1000 .1e-3 
INTG=1 .1e-3 

RESULT=1 .1e-3  ok
>