functionsolveSymRight_C
Extends from Modelica.Icons.Function (Icon for functions).
Information
This function solves the equation
X*A = B
where matrix A with symmetric positive definite matrix. The calculation is rather efficient since symmetrie and decomposition of positive definite matrices is exploited.
Due to symmetry, the matrix A is uniquely defined by
a triangle, i.e. the upper or the lower triangular matrix.
It is assumed, that the input to describe A is either
a Cholesky factor or part of matrix A itself.
This is defined by the user with the boolean inputs isTriangular
and upper which is true when A is already
Cholesky factor and when A is upper triangular,
respectively.
Considering the Cholesky decomposition
T
A = L*L
with lower triangular matrix L the equation above could be rewritten as
T
X*L*L = B
which is solved with BLAS function dtrmm applied to a upper triangular matrix and subsequently to a lower triangular matrix.
In contrast to function solveSymRight this function is implemented in C-code
Inputs
| Type | Name | Default | Description |
|---|---|---|---|
| Real[:,size(A, 1)] | A | Matrix A of X*A = B | |
| Real[:,:] | B | Matrix B of X*op(A) = B | |
| Boolean | isTriangular | false | True if the A is already lower triangular |
| Boolean | upper | false | True if A is upper triAngular |
Outputs
| Type | Name | Default | Description |
|---|---|---|---|
| Real[size(B, 1),size(B, 2)] | X | B | Matrix X such that X*A = B |
| Integer | info |
Revisions
| Date | Author | Comment |
|---|---|---|
| 2010-05-31 | Marcus Baur, DLR-RM | Realization |