Adding LinearAlgebraUtility

src/modules/Utility/CMakeLists.txt

@@ -47,5 +47,6 @@ TARGET_SOURCES(
   ${src_path}/EigenUtility.F90
   ${src_path}/SymUtility.F90
   ${src_path}/TriagUtility.F90
+  ${src_path}/LinearAlgebraUtility.F90
   ${src_path}/Utility.F90
-)
+)

src/modules/Utility/src/LinearAlgebraUtility.F90

@@ -0,0 +1,49 @@
+! This program is a part of EASIFEM library
+! Copyright (C) 2020-2021  Vikas Sharma, Ph.D
+!
+! This program is free software: you can redistribute it and/or modify
+! it under the terms of the GNU General Public License as published by
+! the Free Software Foundation, either version 3 of the License, or
+! (at your option) any later version.
+!
+! This program is distributed in the hope that it will be useful,
+! but WITHOUT ANY WARRANTY; without even the implied warranty of
+! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+! GNU General Public License for more details.
+!
+! You should have received a copy of the GNU General Public License
+! along with this program.  If not, see <https: //www.gnu.org/licenses/>
+!
+
+MODULE LinearAlgebraUtility
+USE GlobalData
+IMPLICIT NONE
+PRIVATE
+
+!----------------------------------------------------------------------------
+!                                                   InvHilbertMatrix@Methods
+!----------------------------------------------------------------------------
+
+INTERFACE
+  MODULE PURE FUNCTION InvHilbertMatrix(n) RESULT(Ans)
+    INTEGER(I4B), INTENT(IN) :: n
+    REAL(DFP) :: Ans(n, n)
+  END FUNCTION InvHilbertMatrix
+END INTERFACE
+
+PUBLIC :: InvHilbertMatrix
+
+!----------------------------------------------------------------------------
+!                                                      HilbertMatrix@Methods
+!----------------------------------------------------------------------------
+
+INTERFACE
+  MODULE PURE FUNCTION HilbertMatrix(n) RESULT(Ans)
+    INTEGER(I4B), INTENT(IN) :: n
+    REAL(DFP) :: Ans(n, n)
+  END FUNCTION HilbertMatrix
+END INTERFACE
+
+PUBLIC :: HilbertMatrix
+
+END MODULE LinearAlgebraUtility

src/modules/Utility/src/Utility.F90

@@ -45,6 +45,7 @@ MODULE Utility
 USE ArangeUtility
 USE SymUtility
 USE TriagUtility
+USE LinearAlgebraUtility
 
 !----------------------------------------------------------------------------
 !

src/submodules/Utility/CMakeLists.txt

@@ -47,4 +47,5 @@ TARGET_SOURCES(
   ${src_path}/EigenUtility@Methods.F90
   ${src_path}/SymUtility@Methods.F90
   ${src_path}/TriagUtility@Methods.F90
+  ${src_path}/LinearAlgebraUtility@Methods.F90
 )

src/submodules/Utility/src/LinearAlgebraUtility@Methods.F90

@@ -0,0 +1,65 @@
+! This program is a part of EASIFEM library
+! Copyright (C) 2020-2021  Vikas Sharma, Ph.D
+!
+! This program is free software: you can redistribute it and/or modify
+! it under the terms of the GNU General Public License as published by
+! the Free Software Foundation, either version 3 of the License, or
+! (at your option) any later version.
+!
+! This program is distributed in the hope that it will be useful,
+! but WITHOUT ANY WARRANTY; without even the implied warranty of
+! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+! GNU General Public License for more details.
+!
+! You should have received a copy of the GNU General Public License
+! along with this program.  If not, see <https: //www.gnu.org/licenses/>
+!
+
+SUBMODULE(LinearAlgebraUtility) Methods
+IMPLICIT NONE
+CONTAINS
+
+!----------------------------------------------------------------------------
+!                                                           IntHilbertMatrix
+!----------------------------------------------------------------------------
+
+MODULE PROCEDURE InvHilbertMatrix
+REAL(DFP) :: p
+REAL(DFP) :: r
+INTEGER(I4B) :: i
+INTEGER(I4B) :: j
+INTEGER(I4B) :: ip1
+
+p = REAL(n, kind=DFP)
+
+DO i = 1, n
+IF (i .NE. 1) p = (REAL(n - i + 1, DFP) * p * REAL(n + i - 1, DFP)) / REAL(i - 1, DFP)**2
+  r = p * p
+  ans(i, i) = r / REAL(2 * i - 1, DFP)
+  IF (i .EQ. n) CYCLE
+  ip1 = i + 1
+  DO j = ip1, n
+    r = (-1) * (REAL(n - j + 1, DFP) * r * (n + j - 1)) / REAL(j - 1, DFP)**2
+    ans(i, j) = r / REAL(i + j - 1, DFP)
+    ans(j, i) = ans(i, j)
+  END DO
+END DO
+END PROCEDURE InvHilbertMatrix
+
+!----------------------------------------------------------------------------
+!                                                           HilbertMatrix
+!----------------------------------------------------------------------------
+
+MODULE PROCEDURE HilbertMatrix
+INTEGER(I4B) :: ii, jj
+REAL(DFP) :: avar
+
+DO jj = 1, n
+  DO ii = 1, n
+    avar = REAL(ii + jj - 1, KIND=DFP)
+    ans(ii, jj) = 1.0_DFP / avar
+  END DO
+END DO
+END PROCEDURE HilbertMatrix
+
+END SUBMODULE Methods