Основы Maple

Robert M. Corless
Department of Applied Mathematics
University of Western Ontario
London, Canada

Copyright 2001 by Robert M. Corless
All rights reserved

Useful one-word commands

Использование монокоманд

Floating-point evaluation

Вычисления с плавающей точкой

Using evalhf

Использование команды evalhf

> restart;

> ProblemB1 := proc(a, h, ya, n, y)
local j,k,c,y1,y2;
y[1,0] := ya[1];
y[2,0] := ya[2];
for k from 1 to n do
c := 0;
for j from 0 to k-1 do
c := c + y[1,j]*y[2,k-j-1];
end do;
y[1,k] := 2*(y[1,k-1] - c)/k;
y[2,k] := (y[2,k-1] - c)/k;
end do;
end proc:

>ya := array(1..2, [1., 3.]):

>n := 200:

>y := array(1..2, 0..n):

>yf := array(1..2, 0..n):

>st := time(): evalhf(ProblemB1(0., 0.1, ya, n, var(y))): etime := time() -st;

>Digits := trunc(evalhf(Digits))+1;

>st := time(): evalf(ProblemB1(0., 0.1, ya, n, yf)): etimef := time() -st;

> etimef/etime;

> y[1,n];

> yf[1,n];

> restart;

> currentdir("C:/local/mpl/adics");

>read "polyflake.mpl";

>bm := evalhf( polyflake(3) );

>bmp := PLOT3D( POINTS(bm) ):

>b := n -> plots[display]( bmp, scaling=CONSTRAINED, orientation=[n,60] ):

> plots[display]( [seq(b(10*n),n=0..35)], insequence=true );

С официального разрешения © 2002 Waterloo Maple, Inc