1 files changed, 47 insertions, 0 deletions
diff --git a/Utilib/src/ALPINVD.f b/Utilib/src/ALPINVD.f
new file mode 100644
index 0000000..69b4bc5
--- /dev/null
+++ b/Utilib/src/ALPINVD.f
@@ -0,0 +1,47 @@
+*DECK ALPINVD
+      SUBROUTINE ALPINVD(M,N,A,AINV)
+*
+*-----------------------------------------------------------------------
+*
+*Purpose:
+* pseudo inversion of a non singular matrix using Gaussian elimination
+* with partial pivoting. Double precision version.
+*
+*Copyright:
+* Copyright (C) 2015 Ecole Polytechnique de Montreal
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU Lesser General Public
+* License as published by the Free Software Foundation; either
+* version 2.1 of the License, or (at your option) any later version.
+*
+*Author(s): A. Hebert
+*
+*Parameters: input
+* M       first dimension of matrix A.
+* N       second dimension of matrix A.
+* A       coefficient matrix to be inverted.
+*
+*Parameters: output
+* AINV    pseudo inverted matrix.
+*
+*-----------------------------------------------------------------------
+*
+      IMPLICIT DOUBLE PRECISION(A-H,O-Z)
+*----
+*  SUBROUTINE ARGUMENTS
+*----
+      INTEGER M,N
+      DOUBLE PRECISION A(M,N),AINV(N,M)
+*----
+*  LOCAL VARIABLES
+*----
+      DOUBLE PRECISION, DIMENSION(:,:), ALLOCATABLE :: B
+*
+      ALLOCATE(B(N,N))
+      B=MATMUL(TRANSPOSE(A),A)
+      CALL ALINVD(N, B, N, IER)
+      IF(IER.NE.0) CALL XABORT('ALPINVD: PSEUDO INVERSION FAILURE.')
+      AINV=MATMUL(B, TRANSPOSE(A))
+      DEALLOCATE(B)
+      RETURN
+      END