!-----------------------------------------------------------------------------------------------------------------------------------
! This file is part of ReMKiT1D.
!
! ReMKiT1D 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.
!
! ReMKiT1D 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 ReMKiT1D. If not, see <https://www.gnu.org/licenses/>.
!
! Copyright 2023 United Kingdom Atomic Energy Authority (stefan.mijin@ukaea.uk)
!-----------------------------------------------------------------------------------------------------------------------------------
module lin_interpnd_class
!! author: Stefan Mijin
!!
!! Houses multi-linear interpolation class on n-dimensional data
use data_kinds ,only: rk, ik
use runtime_constants ,only: debugging, assertions
use god_objects ,only: Object
use assertion_utility ,only: assert, assertIdentical, assertPure
use lin_interp1d_class ,only: Interpolation1D
use flat_nd_data_class ,only: FlatNDData
use support_types ,only: IntArray
implicit none
private
type ,public ,extends(Object) :: InterpolationND
!! Linear interpolation object housing information necessary for linearly interpolating N-dimensional data using weighted averages. If interpolation points are outside of the grid will return 0 for interpolated value. NOTE: Does not support changing the number of interpolation points after the first interpolation call.
type(Interpolation1D) ,dimension(:) ,allocatable ,private :: interpObjs !! Individual 1D interpolation objects. They must correspond to the axes of the data this object should be interpolating
integer(ik) ,dimension(:,:) ,allocatable ,private :: firstDataIndices !! An array of shape (Nd,:) where Nd is the dimensionality of the data being interpolated containing the coordinates of the origin of each hyper-cube of points used in interpolation
type(IntArray) ,dimension(:) ,allocatable ,private :: hyperCube !! Indices of individual hyper-cube points (e.g. [0,1,1,1,0] etc.)
real(rk) ,dimension(:,:) ,allocatable ,private :: weights !! Hypercube vertex weigths (2^Nd,:) for each interpolation point
contains
procedure ,public :: getFirstDataIndicesForDim
procedure ,public :: getInterpWeightsForDim
procedure ,public :: getInterpPointsForDim
procedure ,public :: updateInterpolationPoints
procedure ,public :: interpolate
procedure ,public :: init => initInterpolation
end type InterpolationND
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interface
!-----------------------------------------------------------------------------------------------------------------------------------
pure module subroutine initInterpolation(this,interpolationObjs)
!! Initialization routine for ND interpolation object
class(InterpolationND) ,intent(inout) :: this
type(Interpolation1D) ,dimension(:) ,intent(in) :: interpolationObjs
end subroutine initInterpolation
!-----------------------------------------------------------------------------------------------------------------------------------
pure module subroutine updateInterpolationPoints(this,interpolationPoints)
!! Update the interpolation points and weights of all individual 1D interpolation objects and the weights/data indices used
class(InterpolationND) ,intent(inout) :: this
real(rk) ,dimension(:,:) ,intent(in) :: interpolationPoints
end subroutine updateInterpolationPoints
!-----------------------------------------------------------------------------------------------------------------------------------
pure module function getFirstDataIndicesForDim (this,dim) result(inds)
!! Getter for firstDataIndex of component 1D interpolation object with index dim
class(InterpolationND) ,intent(in) :: this
integer(ik) ,intent(in) :: dim
integer(ik) ,allocatable ,dimension(:) :: inds
end function getFirstDataIndicesForDim
!-----------------------------------------------------------------------------------------------------------------------------------
pure module function getInterpWeightsForDim (this,dim) result(weights)
!! Getter for interpWeights of component 1D interpolation object with index dim
class(InterpolationND) ,intent(in) :: this
integer(ik) ,intent(in) :: dim
real(rk) ,allocatable ,dimension(:) :: weights
end function getInterpWeightsForDim
!-----------------------------------------------------------------------------------------------------------------------------------
pure module function getInterpPointsForDim (this,dim) result(points)
!! Getter for interpolationPoints of component 1D interpolation object with index dim
class(InterpolationND) ,intent(in) :: this
integer(ik) ,intent(in) :: dim
real(rk) ,allocatable ,dimension(:) :: points
end function getInterpPointsFordim
!-----------------------------------------------------------------------------------------------------------------------------------
pure module function interpolate (this,targetArray) result(interpVals)
!! Interpolate FlatNDData onto interpolation points using weighted averages of vertices of the containing hypercube
class(InterpolationND) ,intent(in) :: this
type(FlatNDData) ,intent(in) :: targetArray
real(rk) ,allocatable ,dimension(:) :: interpVals
end function interpolate
!-----------------------------------------------------------------------------------------------------------------------------------
end interface
!-----------------------------------------------------------------------------------------------------------------------------------
end module lin_interpnd_class
!-----------------------------------------------------------------------------------------------------------------------------------
