Add tests for IProductWRTBaseMatFree and PhysderivMatFree

See merge request !34

Update Helmholtz matrix unit test with init_helmholtz.hpp subclass

See merge request !29

Implementation of PhysDerivMatFree

See merge request !27

Add IProductWRTDerivBase unit test with init_ipwrtderivbasefields.hpp subclass

See merge request !32

Update IProductWRTBase unit test with init_ipwrtbasefields.hpp subclass

See merge request !31

Update physderiv unit test

See merge request !30

Update BwdTrans unit test with init_bwdtransfields.hpp subclass

See merge request !28

Update readme cmake

See merge request !33

Refactor PhysDeriv, IProductWRTDerivBase, and Helmholtz operators

See merge request !26

Change tests to compare other implementations with StdMat version

See merge request !23

Implementation of IProductWRTBaseMatFree

See merge request !25

Basic implementation of Matrix-free BwdTrans and padding feature in Field

See merge request !22

Add README.md

See merge request !18

Implement CUDA Helmholtz sum-factorization kernels

See merge request !20

Implement CUDA IProductWRTDerivBase sum-factorization kernels

See merge request !14

Add error message if both CUDA and SIMD are enabled.

See merge request !19

Fix tests missing main function

See merge request !21

Implement CUDA PhysDeriv sum-factorization kernels

See merge request !13

Implement CUDA IProductWRTBase sum-factorization kernels

See merge request !12

Fix memory leak with Field objects not being deleted.

See merge request !16