Adding Span and Memory about csparse.net

[wo80]

Hello! Thank you sincerely for providing a nice sparse matrix library.

Hello @delicioustuna , thanks for your kind words!

Adding Span support to the Solve methods shouldn't be difficult. Would you like to go ahead and create a pull request?

[delicioustuna]

Thank you for your prompt response.
I have created a pull request.

#42

I need to add a reference to System.Memory.dll, is this an acceptable change?

[delicioustuna]

Thank you for your reply and for pointing out the additional dependency.

I too would prefer a format with zero dependencies whenever possible, and since there was no better alternative for Span than to refer to Sytem.Memory.dll, this is the way to do it. I hope this will not be a problem for other users.

I will make the changes you suggested. Please wait a moment.

[wo80]

I need to add a reference to System.Memory.dll, is this an acceptable change?

Yes, that's ok for now. Though I like a "zero dependencies" approach, this is much cleaner than having #if NETCOREAPP2_1_OR_GREATER all across the code. I might change that later on, in case I get any complaints.

But please add the dependency only where necessary, so

<ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
  <PackageReference Include="System.Memory" Version="4.5.5" />
</ItemGroup>