Scilab Function insertion - matrix and list insertion 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
i and j, may be:
-
real scalars or vectors or matrices with positive elements.
*
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 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 which 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,'*')
-
vector of boolean. If an index (i or j )is a vector of booleans it is interpreted as find(i) or respectively find(j)
-
a polynomial. 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