insertion
insertion, assignation — partial variable assignation
or modification
Calling sequence
x(i,j)=a
x(i)=a
l(i)=a
l(k1)...(kn)(i)=a or l(list(k1,...,kn,i))=a
l(k1)...(kn)(i,j)=a or l(list(k1,...,kn,list(i,j))=a
Parameters
| x | : matrix of any kind (constant, sparse, polynomial,...) |
| l | : list |
| i,j | : indices |
| k1,...kn | : indices with integer value |
| a | : new entry value |
Description
| MATRIX CASE | if x is a matrix the indices i and j, may be: | Real scalars or vectors or matrices | In this case the values given as indices should be positive and
it is only their integer part which taken into account. | if a is a matrix with
dimensions
(size(i,'*'),size(j,'*')),
x(i,j)=a returns a new x matrix
such as x(int(i(l)),int(j(k)))=a(l,k) for
l from 1 to
size(i,'*') and k from
1 to size(j,'*'), other initial
entries of x are unchanged. | | if a is a scalar
x(i,j)=a returns a new x matrix
such as x(int(i(l)),int(j(k)))=a for
l from 1 to size(i,'*')
and k from 1 to
size(j,'*'), other initial entries
of x are unchanged. | | If i or j
maximum value exceed corresponding x matrix
dimension, array x is previously extended to the
required dimensions with zeros entries for standard
matrices, 0 length character string for string matrices and
false values for boolean matrices.
| | x(i,j)=[] kills rows
specified by i if j matches all
columns of x or kills columns specified by
j if i matches all rows of
x. In other cases x(i,j)=[]
produce an error. | | x(i)=a with a a
vector returns a new x matrix such as
x(int(i(l)))=a(l) for l from 1 to
size(i,'*') , other initial entries
of x are unchanged. | | x(i)=a with a a
scalar returns a new x matrix such as
x(int(i(l)))=a for l from 1 to
size(i,'*') , other initial entries
of x are unchanged.
If i maximum value exceed
size(x,1), x is previously
extended to the required dimension with zeros entries for
standard matrices, 0 length character string for string
matrices and false values for boolean matrices.
| if | x is a 1x1
matrix a may be a row (respectively a
column) vector with dimension
size(i,'*'). Resulting
x matrix is a row (respectively a column)
vector
| | if | x is a row
vector a must be a row vector with
dimension size(i,'*') | | if | x is a column
vector a must be a column vector with
dimension size(i,'*') | | if | x is a general
matrix a must be a row or column vector
with dimension size(i,'*') and
i maximum value cannot exceed
size(x,'*'),
|
| | x(i)=[] kills entries
specified by i.
|
| | The : symbol | the : symbol stands for "all elements". | x(i,:)=a is interpreted as
x(i,1:size(x,2))=a | | x(:,j)=a is interpreted as
x(1:size(x,1),j)=a | | x(:)=a returns in
x the a matrix reshaped
according to x
dimensions. size(x,'*') must be
equal to size(a,'*') |
| | Vectors of boolean | If an index (i or j )is a vector
of booleans it is interpreted as find(i) or
respectively find(j) | | Polynomials | If an index (i or j )is a vector of
polynomials or implicit polynomial vector it is interpreted
as horner(i,m) or respectively
horner(j,n) where m and
n are associated x dimensions.
Even if this feature works for all polynomials, it is
recommended to use polynomials in $ for
readability. |
|
| LIST OR TLIST CASE | | If they are present
the ki give the path to a sub-list entry of
l data structure. They allow a recursive insertion
without intermediate copies. The l(k1)...(kn)(i)=a
and l(list(k1,...,kn,i)=a) instructions are
interpreted as: lk1 = l(k1) .. = .. lkn = lkn-1(kn) lkn(i) = a lkn-1(kn) = lkn .. = .. l(k1) = lk1
And the l(k1)...(kn)(i,j)=a and l(list(k1,...,kn,list(i,j))=a
instructions are interpreted as: lk1 = l(k1) .. = .. lkn = lkn-1(kn)lkn(i,j) = a lkn-1(kn) = lkn .. = .. l(k1)= lk1 | | i may be : | a real non negative scalar.
l(0)=a adds an entry on the "left"
of the list l(i)=a sets the i
entry of the list l to a. if
i>size(l), l is previously
extended with zero length entries (undefined).
l(i)=null() suppress the ith list
entry. | | a polynomial. If i is a
polynomial it is interpreted as horner(i,m)
where m=size(l). Even if this feature works
for all polynomials, it is recommended to use polynomials
in $ for readability. |
| | k1,..kn may be : |
real positive scalar. | | a polynomial,interpreted as
horner(ki,m) where m is the
corresponding sub-list size. | | a character string associated with a
sub-list entry name. |
|
|
Remarks
For soft coded matrix types such as rational functions and state space linear systems, x(i) syntax may not be used for vector entry insertion due to confusion with list entry insertion. x(1,j) or x(i,1) syntax must be used.
Examples
// MATRIX CASE
a=[1 2 3;4 5 6]
a(1,2)=10
a([1 1],2)=[-1;-2]
a(:,1)=[8;5]
a(1,3:-1:1)=[77 44 99]
a(1)=%s
a(6)=%s+1
a(:)=1:6
a([%t %f],1)=33
a(1:2,$-1)=[2;4]
a($:-1:1,1)=[8;7]
a($)=123
//
x='test'
x([4 5])=['4','5']
//
b=[1/%s,(%s+1)/(%s-1)]
b(1,1)=0
b(1,$)=b(1,$)+1
b(2)=[1 2] // the numerator
// LIST OR TLIST CASE
l=list(1,'qwerw',%s)
l(1)='Changed'
l(0)='Added'
l(6)=['one more';'added']
//
//
dts=list(1,tlist(['x';'a';'b'],10,[2 3]));
dts(2).a=33
dts(2)('b')(1,2)=-100
See also
find, horner, parents, extraction
