student::equateMatrix --
build a matrix equation
Introductionstudent::equateMatrix(A, vars) returns the
matrix equation
A[1..r,1..c-1] * vars = A[1..r,c..c]
Call(s)student::equateMatrix(A, vars)
ParametersA |
- | matrix (of category Cat::Matrix) over a Cat::Field |
vars |
- | list of indeterminates |
Returnsan expression of the domain type DOM_EXPR and of type
"equal".
Related
Functions
Detailsstudent::equateMatrix(A,vars)
returns the matrix equation
A[1..r,1..c-1] * X = A[1..r,c..c]where r and c are the row and column number of
A, and x_1, ..., x_r are the elements of
vars.vars must match
the row number of the matrix A.
Example
1Let us construct the equation A*X=b. First we construct A and b:
>> Ab := matrix( [[1,2,3],[-1,3,0]] )
+- -+
| 1, 2, 3 |
| |
| -1, 3, 0 |
+- -+
Here we have A = [[1,2],[-1,3]] and b = [3,0]. Now we construct the equation A*X=b:
>> student::equateMatrix( Ab,[x1,x2] )
+- -+ +- -+
| x1 + 2 x2 | | 3 |
| | = | |
| - x1 + 3 x2 | | 0 |
+- -+ +- -+
Example
2We should be carefull to use the right dimension of the matrix and the indeterminates:
>> Ab := matrix( [[1,2,3],[-1,3,0]] )
+- -+
| 1, 2, 3 |
| |
| -1, 3, 0 |
+- -+
>> student::equateMatrix( Ab,[x1,x2,x3] )
Error: dimension of matrix and number of vars don't match [stu\
dent::equateMatrix]