MaplePrimes - answers and comments on Question, comparing two arrays

Array comparison

mois — Thu, 12 Nov 2009 16:15:59 Z

with(ArrayTools):

A1:=Array([1,2,3,4,5,6,7]);
A2:=Array([1,2,3.3,4.4,5.5,6.0,7.0]); # two Arrays

d1:=A1-~A1;
d2:=A2-~A1; #differences between two Arrays

IsZero(d1);
IsZero(d2); # if true then Arrays have equal elements

ArrayTools[IsEqual]

Joe Riel — Fri, 13 Nov 2009 04:06:09 Z

Using ?ArrayTools[IsEqual] avoids creating the intermediate array.

hi

haider — Mon, 16 Nov 2009 15:51:52 Z

This is regarding using (ArrayTools) IsEqual ?

If I have two arrays each 3 dimensional, and i want to comapre certain arrays out of them.

eg., consider Array A(1..n,1..m,1..p).

if i compare A[1][2] to A[2][5] (each of which must have 100 elements). using ArrayTools(IsEqual) then this command gives a wrong answer?

Exactly I used the command

IsEqual(A[1][2] , A[2][5])

I have already declared the array in the following way A:=Array(1..n,1..m,1..p)

What would u suggest, am i going in the coorect direction or there is a different command for this.

Plz. help

hyder

an IsEqual example

Doug Meade — Mon, 16 Nov 2009 21:22:22 Z

Without seeing exactly what you are doing it is difficult to explain what you are reporting. Here's a simple illustration to show that this idea can work.

with( ArrayTools ):
A := Array( 1..5, 1..5, 1..5, (i,j,k)->i+k ):
IsEqual( A[1][2], A[2][5] );
                                    false
IsEqual( A[2][2], A[2][5] );
                                    true

Did you, by chance, forget to load the ArrayTools package?

Does this help?

Doug

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thanks

haider — Thu, 12 Nov 2009 21:54:36 Z

thanks mols

it worked perfectly well.....

hyder

thanks

haider — Fri, 13 Nov 2009 11:48:54 Z

i found this way even more efficient. thanks alot..

hyder