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The Maxima on-line user's manual

Algebra Calculator

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Indices Calculator

Indices

Function: indices (<expr>) Returns a list of two elements. The first is a list of the free indices in <expr> (those that occur only once). The second is the list of the dummy indices in <expr> (those that occur exactly twice) as the following example demonstrates.

load(itensor);
 ishow(a([i,j],[k,l],m,n)*b([k,o],[j,m,p],q,r));
 indices(%);
32^1/5

          (%i1) load(itensor);
          (%o1)      /share/tensor/itensor.lisp
          (%i2) ishow(a([i,j],[k,l],m,n)*b([k,o],[j,m,p],q,r))$
                                          k l      j m p
          (%t2)                          a        b
                                          i j,m n  k o,q r
          (%i3) indices(%);
          (%o3)                 [[l, p, i, n, o, q, r], [k, j, m]]

A tensor product containing the same index more than twice is syntactically illegal. indices attempts to deal with these expressions in a reasonable manner; however, when it is called to operate upon such an illegal expression, its behavior should be considered undefined.

There are also some inexact matches for indices. Try ?? indices to see them.

(%o1)                                true
(%i2) 

Indices Example

Related Examples

indices-load

load(itensor);

ishow(a([i,j],[k,l],...

indices(%);

Calculate

indices-lambda-length-makelist-permut-sublist_indices

alist: makelist(a[ii]...

plist: permut(alist);

perm: plist[3];

Calculate

indices-load

load(itensor);

ishow(a([i,j],[k,l],...

indices(%);

Calculate

indices-lambda-length-makelist-permut-sublist_indices

alist: makelist(a[ii]...

plist: permut(alist);

ulist: makelist(false...

Calculate

indices-load

load(itensor);

ishow(a([i,j],[k,l],...

indices(%);

Calculate

indices-load

load(itensor);

ishow(a([i,j],[k,l],...

indices(%);

Calculate

indices-load

load(itensor);

ishow(a([i,j],[k,l],...

indices(%);

Calculate

indices-load

load(itensor);

ishow(a([i,j],[k,l],...

indices(%);

Calculate

indices-load

load(itensor);

ishow(a([i,j],[k,l],...

indices(%);

Calculate

indices-lambda-sublist_indices

L:[1,1,3,2,4];

sublist_indices(L,lam...

Calculate