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Invert


Unit:SDL_matrix
Class:TMatrix
Declaration:function Invert: boolean;

The method Invert calculates the inverse of a quadratic matrix and stores the result on top of the original matrix (thereby destroying the original contents). The matrix inversion is carried out using the LU-decomposition procedure (decomposition into two triangle matrices). It must not be applied to non-quadratic matrices.

The function returns the value TRUE, if the inversion has been completed successfully. In case of a FALSE value, the resulting matrix is undefined. The following reasons can cause a failure of the method Invert :

  • the matrix is not quadratic
  • the routine runs out of heap memory
  • the matrix is singular

Invert increments the global variable ProcStat and calls the feedback routine MathFeedBackProc in order to allow feedback to the user during time consuming calculations. The Invert function can be terminated by setting the global variable AbortMathProc to TRUE.

Hint: The lower limit of the necessary free heap memory can be calculated by the equation n*((n+2)*8+2) (bytes), with 'n' being the number of columns of the matrix.

Example: This method is used in the following example program (see http://www.lohninger.com/examples.html for downloading the code): invmat



Last Update: 2016-Jun-28