update readme, version bump

Author: j-fu

Project.toml

@@ -1,7 +1,7 @@
 name = "ExtendableSparse"
 uuid = "95c220a8-a1cf-11e9-0c77-dbfce5f500b3"
 authors = ["Juergen Fuhrmann <[email protected]>"]
-version = "0.2.7"
+version = "0.3.0"
 
 [deps]
 DocStringExtensions = "ffbed154-4ef7-542d-bbb7-c09d3a79fcae"

README.md

@@ -8,21 +8,31 @@
 
 Sparse matrix class with efficient successive insertion of entries and entry update.
 
-Without an intermediate data structure, efficient successive insertion/update of possibly duplicate entries in random order into a standard compressed colume storage structure appears to be not possible. The package introduces `ExtendableSparseMatrix`, a delegating wrapper containing a Julia standard `SparseMatrixCSC` struct for performing linear algebra operations and a `SparseMatrixLNK` struct realising a linked list based (but realised in vectors) format collecting new entries.
+Without an intermediate data structure, efficient successive insertion/update of possibly duplicate entries in random order into a standard compressed column storage structure appears to be not possible. The package introduces `ExtendableSparseMatrix`, a delegating wrapper containing a Julia standard `SparseMatrixCSC` struct for performing linear algebra operations and a `SparseMatrixLNK` struct realising a linked list based (but realised in vectors) format collecting new entries.
 
 The later is modeled after the linked list sparse matrix format described in the [whitepaper](https://www-users.cs.umn.edu/~saad/software/SPARSKIT/paper.ps) by Y. Saad. See also exercise P.3-16  in his [book](https://www-users.cs.umn.edu/~saad/IterMethBook_2ndEd.pdf).
 
 Any linear algebra method on `ExtendableSparseMatrix` starts with a `flush!` method which adds the LNK entries and the existing CSC entries into a new CSC struct and resets the LNK struct.
 
 `ExtendableSparseMatrix` is aimed to work as a drop-in replacement to `SparseMatrixCSC` in finite element and finite volume codes especally in those cases where the sparsity structure is hard to detect a priori and where working with an intermediadte COO representation appears to be not convenient.
 
+In particular, it cooperates with [ForwardDiff.jl](https://github.com/JuliaDiff/ForwardDiff.jl) when it comes to the assembly of a sparse jacobian. For a function 'f!(y,x)' returning it's result in a vector `y`, one can use e.g.
+````
+x=...
+y=zeros(n)
+dresult=DiffResults.DiffResult(zeros(n),ExtendableSparseMatrix(n,n))
+x=ForwardDiff.jacobian!(dresult,f!,y,x)
+jac=DiffResults.jacobian(dresult)
+h=jac\x
+````
+
 In addition, the package provides a method `updateindex!(A,op,v,i,j)` for both `SparseMatrixCSC` and for `ExtendableSparse` which allows to update a matrix element with one index search instead of two. It allows to replace e.g. `A[i,j]+=v` by `updateindex!(A,+,v,i,j)`. The former operation is lowered to 
 ````
 %1 = Base.getindex(A, 1, 2)
 %2 = %1 + 3
 Base.setindex!(A, %2, 1, 2)
 ````
- triggering two index searches, one for `getindex!` and another one for `setindex!`.
+triggering two index searches, one for `getindex!` and another one for `setindex!`.
 
 
 

docs/src/changes.md

@@ -1,4 +1,8 @@
 # Changes
+## v0.3.0, April 10, 2020
+- Don't create new entry if the value to be assigned is zero, making things consistent with SparseMatrixCSC and ForwardDiff 
+  as suggested by @MaximilianJHuber
+
 ## v0.2.5, Jan 26, 2020
 - fixed allocations in  Base.+
 - added updateindex! method