Add mutating arithmetic for SRows

src/Sparse/Row.jl

@@ -447,15 +447,17 @@
 #  Inplace scaling
 #
 ################################################################################
+
 @doc raw"""
     scale_row!(a::SRow, b::NCRingElem) -> SRow
 
 Returns the (left) product of $b \times a$ and reassigns the value of $a$ to this product.
 For rows, the standard multiplication is from the left.
 """
 function scale_row!(a::SRow{T}, b::T) where T
-  @assert !iszero(b)
-  if isone(b)
+  if iszero(b)
+    return empty!(a)
+  elseif isone(b)
     return a
   end
   i = 1
@@ -465,20 +467,23 @@
       deleteat!(a.values, i)
       deleteat!(a.pos, i)
     else
-     i += 1
+      i += 1
     end
   end
   return a
 end
 
+scale_row!(a::SRow, b) = scale_row!(a, base_ring(a)(b))
+
 @doc raw"""
     scale_row_right!(a::SRow, b::NCRingElem) -> SRow
 
 Returns the (right) product of $a \times b$ and modifies $a$ to this product.
 """
 function scale_row_right!(a::SRow{T}, b::T) where T
-  @assert !iszero(b)
-  if isone(b)
+  if iszero(b)
+    return empty!(a)
+  elseif isone(b)
     return a
   end
   i = 1
@@ -488,16 +493,20 @@
       deleteat!(a.values, i)
       deleteat!(a.pos, i)
     else
-     i += 1
+      i += 1
     end
   end
   return a
 end
 
+scale_row_right!(a::SRow, b) = scale_row_right!(a, base_ring(a)(b))
+
 function scale_row_left!(a::SRow{T}, b::T) where T
   return scale_row!(a,b)
 end
 
+scale_row_left!(a::SRow, b) = scale_row_left!(a, base_ring(a)(b))
+
 ################################################################################
 #
 #  Addition
@@ -518,10 +527,10 @@
     if length(B) == 0
       return A
     else
-      return add_scaled_row(B, A, base_ring(B)(-1))
+      return add_scaled_row(B, A, -1)
     end
   end
-  return add_scaled_row(B, A, base_ring(A)(-1))
+  return add_scaled_row(B, A, -1)
 end
 
 function -(A::SRow{T}) where {T}
@@ -683,10 +692,10 @@
 
 Returns the row $c A + B$.
 """
-add_scaled_row(a::SRow{T}, b::SRow{T}, c::T) where {T} = add_scaled_row!(a, deepcopy(b), c)
+add_scaled_row(a::SRow{T}, b::SRow{T}, c) where {T} = add_scaled_row!(a, deepcopy(b), c)
 
-add_left_scaled_row(a::SRow{T}, b::SRow{T}, c::T) where {T} = add_left_scaled_row!(a, deepcopy(b), c)
-add_right_scaled_row(a::SRow{T}, b::SRow{T}, c::T) where {T} = add_right_scaled_row!(a, deepcopy(b), c)
+add_left_scaled_row(a::SRow{T}, b::SRow{T}, c) where {T} = add_left_scaled_row!(a, deepcopy(b), c)
+add_right_scaled_row(a::SRow{T}, b::SRow{T}, c) where {T} = add_right_scaled_row!(a, deepcopy(b), c)
 
 
 
@@ -696,7 +705,9 @@
 Adds the left scaled row $c A$ to $B$.
 """
 function add_scaled_row!(a::SRow{T}, b::SRow{T}, c::T, ::Val{left_side} = Val(true)) where {T, left_side}
-  @assert a !== b
+  if a === b
+    a = deepcopy(a)
+  end
   i = 1
   j = 1
   t = base_ring(a)()
@@ -735,17 +746,116 @@
   return b
 end
 
+add_scaled_row!(a::SRow{T}, b::SRow{T}, c) where {T} = add_scaled_row!(a, b, base_ring(a)(c))
+
+add_scaled_row!(a::SRow{T}, b::SRow{T}, c, side::Val) where {T} = add_scaled_row!(a, b, base_ring(a)(c), side)
+
 # ignore tmp argument
-add_scaled_row!(a::SRow{T}, b::SRow{T}, c::T, tmp::SRow{T}) where T = add_scaled_row!(a, b, c)
+add_scaled_row!(a::SRow{T}, b::SRow{T}, c, tmp::SRow{T}) where T = add_scaled_row!(a, b, c)
 
-add_left_scaled_row!(a::SRow{T}, b::SRow{T}, c::T) where T = add_scaled_row!(a, b, c)
+add_left_scaled_row!(a::SRow{T}, b::SRow{T}, c) where T = add_scaled_row!(a, b, c)
 
 @doc raw"""
     add_right_scaled_row!(A::SRow{T}, B::SRow{T}, c::T) -> SRow{T}
 
-Return the right scaled row $c A$ to $B$ by changing $B$ in place.
+Return the right scaled row $A c$ to $B$ by changing $B$ in place.
 """
-add_right_scaled_row!(a::SRow{T}, b::SRow{T}, c::T) where T = add_scaled_row!(a, b, c, Val(false))
+add_right_scaled_row!(a::SRow{T}, b::SRow{T}, c) where T = add_scaled_row!(a, b, c, Val(false))
+
+
+################################################################################
+#
+#  Mutating arithmetics
+#
+################################################################################
+
+function zero!(z::SRow)
+  return empty!(z)
+end
+
+function neg!(z::SRow{T}, x::SRow{T}) where T
+  if z === x
+    return neg!(x)
+  end
+  swap!(z, -x)
+  return z
+end
+
+function neg!(z::SRow)
+  for i in 1:length(z)
+    z.values[i] = neg!(z.values[i])
+  end
+  return z
+end
+
+function add!(z::SRow{T}, x::SRow{T}, y::SRow{T}) where T
+  if z === x
+    return add!(x, y)
+  elseif z === y
+    return add!(y, x)
+  end
+  swap!(z, x + y)
+  return z
+end
+
+function add!(z::SRow{T}, x::SRow{T}) where T
+  if z === x
+    return scale_row!(z, 2)
+  end
+  return add_scaled_row!(x, z, one(base_ring(x)))
+end
+
+function sub!(z::SRow{T}, x::SRow{T}, y::SRow{T}) where T
+  if z === x
+    return sub!(x, y)
+  elseif z === y
+    return neg!(sub!(y, x))
+  end
+  swap!(z, x - y)
+  return z
+end
+
+function sub!(z::SRow{T}, x::SRow{T}) where T
+  if z === x
+    return empty!(z)
+  end
+  return add_scaled_row!(x, z, -1)
+end
+
+function mul!(z::SRow{T}, x::SRow{T}, c) where T
+  if z === x
+    return scale_row_right!(x, c)
+  end
+  swap!(z, x * c)
+  return z
+end
+
+function mul!(z::SRow{T}, c, y::SRow{T}) where T
+  if z === y
+    return scale_row_left!(y, c)
+  end
+  swap!(z, c * y)
+  return z
+end
+
+function addmul!(z::SRow{T}, x::SRow{T}, y) where T
+  if z === x
+    return scale_row_right!(x, y+1)
+  end
+  return add_right_scaled_row!(x, z, y)
+end
+
+function addmul!(z::SRow{T}, x, y::SRow{T}) where T
+  if z === x
+    return scale_row_left!(y, x+1)
+  end
+  return add_left_scaled_row!(y, z, x)
+end
+
+
+# ignore temp variable
+addmul!(z::SRow{T}, x::SRow{T}, y, t) where T = addmul!(z, x, y)
+addmul!(z::SRow{T}, x, y::SRow{T}, t) where T = addmul!(z, x, y)
 
 
 ################################################################################