Joe Riel

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18 years, 223 days

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These are answers submitted by Joe Riel

First, you need to define what you mean by, say, [a,b] < [c,d]. Does that mean (a < c) and (b < d)? Assuming so, you could try something like
# This isn't particularly efficient

ListInequality := proc(f,v1::list,v2::list)::truefalse;
    evalb(foldl(`and`, zip(f, v1, v2)[]))
end proc:

`&<` := proc(v1,v2) ListInequality(`<`,v1,v2) end proc:

vf := v -> piecewise((3*v) &< [6,1] and v &< [-2,5],  [3,4] + 3*v
                     ,(2*v) &< [8,-4] and (-v) &< [2,-5], [1,9] + 2*v
                     ,(-3*v) &< [-6,-1] and (-2*v) &< [-8,4], [9,5]

              [-6, 4]
The usual technique would be to use fprintf. For example,
deq1 := (t+1)^2*diff(y(t),t,t) + (t+1)*diff(y(t),t) 
        + ((t+1)^2-0.25)*y(t) = 0:
ic1 := (y(0) = 0.6713967071418030
        ,D(y)(0) = 0.09540051444747446):
dsol1 := dsolve({deq1,ic1}, numeric, range=0..1):

file := "data.txt":
    fd := fopen(file,'WRITE','TEXT');
    for tt from 0 to 1 by 0.1 do
        fprintf(fd,"%a %a %a\n"
finally close(file)
end try:
Another way to input the symbol, particularly useful for those of us who prefer maple input format, is to just type `∂`. Note the ampersand and semicolon in the backquotes, they delimit the base name and are displayed as a single symbol in the Standard GUI. You can extend this technique to string together symbols. For example, if you want to create `∂𝔅` type `PartialD;𝔅`, where `𝔅` is the Fraktur "B" (`𝔅`). As a side note, to print `∂𝔅` in this forum, use the <maple> tag: <maple>`∂𝔅`</maple>. Use lprint to find the name of a particular symbol. For example, in maple input mode, go to an empty input line, type ctrl-R (enter 2D math mode), select the symbol of interest from a palette, then hit return. The symbol is displayed. Next, type lprint(%);. That prints the character version of the symbol.
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