mat: add NonZeroDoer interfaces and implementations
Also clean up some documentation and missing type checks related to
tests for NonZeroDoers.
MODIFY
mat/band.go
mat/band.go
@@ -13,6 +13,10 @@ var (
_ Matrix = bandDense
_ Banded = bandDense
_ RawBander = bandDense
+
+ _ NonZeroDoer = bandDense
+ _ RowNonZeroDoer = bandDense
+ _ ColNonZeroDoer = bandDense
)
// BandDense represents a band matrix in dense storage format.
@@ -39,6 +43,12 @@ type RawBander interface {
RawBand() blas64.Band
}
+// A MutableBanded can set elements of a band matrix.
+type MutableBanded interface {
+ Banded
+ SetBand(i, j int, v float64)
+}
+
var (
_ Matrix = TransposeBand{}
_ Banded = TransposeBand{}
@@ -173,3 +183,46 @@ func (b *BandDense) TBand() Banded {
func (b *BandDense) RawBand() blas64.Band {
return b.mat
}
+
+// DoNonZero calls the function fn for each of the non-zero elements of b. The function fn
+// takes a row/column index and the element value of b at (i, j).
+func (b *BandDense) DoNonZero(fn func(i, j int, v float64)) {
+ for i := 0; i < min(b.mat.Rows, b.mat.Cols+b.mat.KL); i++ {
+ for j := max(0, i-b.mat.KL); j < min(b.mat.Cols, i+b.mat.KU+1); j++ {
+ v := b.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ }
+}
+
+// DoRowNonZero calls the function fn for each of the non-zero elements of row i of b. The function fn
+// takes a row/column index and the element value of b at (i, j).
+func (b *BandDense) DoRowNonZero(i int, fn func(i, j int, v float64)) {
+ if i < 0 || b.mat.Rows <= i {
+ panic(ErrRowAccess)
+ }
+ for j := max(0, i-b.mat.KL); j < min(b.mat.Cols, i+b.mat.KU+1); j++ {
+ v := b.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+}
+
+// DoColNonZero calls the function fn for each of the non-zero elements of column j of b. The function fn
+// takes a row/column index and the element value of b at (i, j).
+func (b *BandDense) DoColNonZero(j int, fn func(i, j int, v float64)) {
+ if j < 0 || b.mat.Cols <= j {
+ panic(ErrColAccess)
+ }
+ for i := 0; i < min(b.mat.Rows, b.mat.Cols+b.mat.KL); i++ {
+ if i-b.mat.KL <= j && j < i+b.mat.KU+1 {
+ v := b.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ }
+}

MODIFY
mat/matrix.go
mat/matrix.go
@@ -182,6 +182,24 @@ type RawVectorer interface {
RawVector() blas64.Vector
}
+// A NonZeroDoer can call a function for each non-zero element of the receiver.
+// The parameters of the function are the element indices and its value.
+type NonZeroDoer interface {
+ DoNonZero(func(i, j int, v float64))
+}
+
+// A RowNonZeroDoer can call a function for each non-zero element of a row of the receiver.
+// The parameters of the function are the element indices and its value.
+type RowNonZeroDoer interface {
+ DoRowNonZero(i int, fn func(i, j int, v float64))
+}
+
+// A ColNonZeroDoer can call a function for each non-zero element of a column of the receiver.
+// The parameters of the function are the element indices and its value.
+type ColNonZeroDoer interface {
+ DoColNonZero(j int, fn func(i, j int, v float64))
+}
+
// TODO(btracey): Consider adding CopyCol/CopyRow if the behavior seems useful.
// TODO(btracey): Add in fast paths to Row/Col for the other concrete types
// (TriDense, etc.) as well as relevant interfaces (RowColer, RawRowViewer, etc.)

MODIFY
mat/matrix_test.go
mat/matrix_test.go
@@ -521,3 +521,94 @@ func TestTrace(t *testing.T) {
}
testOneInputFunc(t, "Trace", f, denseComparison, sameAnswerFloat, isAnyType, isSquare)
}
+
+func TestDoer(t *testing.T) {
+ type MatrixDoer interface {
+ Matrix
+ NonZeroDoer
+ RowNonZeroDoer
+ ColNonZeroDoer
+ }
+ ones := func(n int) []float64 {
+ data := make([]float64, n)
+ for i := range data {
+ data[i] = 1
+ }
+ return data
+ }
+ for i, m := range []MatrixDoer{
+ NewTriDense(3, Lower, ones(3*3)),
+ NewTriDense(3, Upper, ones(3*3)),
+ NewBandDense(6, 6, 1, 1, ones(3*6)),
+ NewBandDense(6, 10, 1, 1, ones(3*6)),
+ NewBandDense(10, 6, 1, 1, ones(7*3)),
+ NewSymBandDense(3, 0, ones(3)),
+ NewSymBandDense(3, 1, ones(3*(1+1))),
+ NewSymBandDense(6, 1, ones(6*(1+1))),
+ NewSymBandDense(6, 2, ones(6*(2+1))),
+ } {
+ r, c := m.Dims()
+
+ want := Sum(m)
+
+ // got and fn sum the accessed elements in
+ // the Doer that is being operated on.
+ // fn also tests that the accessed elements
+ // are within the writable areas of the
+ // matrix to check that only valid elements
+ // are operated on.
+ var got float64
+ fn := func(i, j int, v float64) {
+ got += v
+ switch m := m.(type) {
+ case MutableTriangular:
+ m.SetTri(i, j, v)
+ case MutableBanded:
+ m.SetBand(i, j, v)
+ case MutableSymBanded:
+ m.SetSymBand(i, j, v)
+ default:
+ panic("bad test: need mutable type")
+ }
+ }
+
+ panicked, message := panics(func() { m.DoNonZero(fn) })
+ if panicked {
+ t.Errorf("unexpected panic for Doer test %d: %q", i, message)
+ continue
+ }
+ if got != want {
+ t.Errorf("unexpected Doer sum: got:%f want:%f", got, want)
+ }
+
+ // Reset got for testing with DoRowNonZero.
+ got = 0
+ panicked, message = panics(func() {
+ for i := 0; i < r; i++ {
+ m.DoRowNonZero(i, fn)
+ }
+ })
+ if panicked {
+ t.Errorf("unexpected panic for RowDoer test %d: %q", i, message)
+ continue
+ }
+ if got != want {
+ t.Errorf("unexpected RowDoer sum: got:%f want:%f", got, want)
+ }
+
+ // Reset got for testing with DoColNonZero.
+ got = 0
+ panicked, message = panics(func() {
+ for j := 0; j < c; j++ {
+ m.DoColNonZero(j, fn)
+ }
+ })
+ if panicked {
+ t.Errorf("unexpected panic for ColDoer test %d: %q", i, message)
+ continue
+ }
+ if got != want {
+ t.Errorf("unexpected ColDoer sum: got:%f want:%f", got, want)
+ }
+ }
+}

MODIFY
mat/symband.go
mat/symband.go
@@ -16,6 +16,10 @@ var (
_ Banded = symBandDense
_ RawSymBander = symBandDense
_ MutableSymBanded = symBandDense
+
+ _ NonZeroDoer = symBandDense
+ _ RowNonZeroDoer = symBandDense
+ _ ColNonZeroDoer = symBandDense
)
// SymBandDense represents a symmetric band matrix in dense storage format.
@@ -41,7 +45,7 @@ type RawSymBander interface {
// NewSymBandDense creates a new SymBand matrix with n rows and columns. If data == nil,
// a new slice is allocated for the backing slice. If len(data) == n*(k+1),
// data is used as the backing slice, and changes to the elements of the returned
-// BandDense will be reflected in data. If neither of these is true, NewSymBandDense
+// SymBandDense will be reflected in data. If neither of these is true, NewSymBandDense
// will panic. k must be at least zero and less than n, otherwise NewBandDense will panic.
//
// The data must be arranged in row-major order constructed by removing the zeros
@@ -126,3 +130,46 @@ func (s *SymBandDense) TBand() Banded {
func (s *SymBandDense) RawSymBand() blas64.SymmetricBand {
return s.mat
}
+
+// DoNonZero calls the function fn for each of the non-zero elements of s. The function fn
+// takes a row/column index and the element value of s at (i, j).
+func (s *SymBandDense) DoNonZero(fn func(i, j int, v float64)) {
+ for i := 0; i < s.mat.N; i++ {
+ for j := max(0, i-s.mat.K); j < min(s.mat.N, i+s.mat.K+1); j++ {
+ v := s.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ }
+}
+
+// DoRowNonZero calls the function fn for each of the non-zero elements of row i of s. The function fn
+// takes a row/column index and the element value of s at (i, j).
+func (s *SymBandDense) DoRowNonZero(i int, fn func(i, j int, v float64)) {
+ if i < 0 || s.mat.N <= i {
+ panic(ErrRowAccess)
+ }
+ for j := max(0, i-s.mat.K); j < min(s.mat.N, i+s.mat.K+1); j++ {
+ v := s.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+}
+
+// DoColNonZero calls the function fn for each of the non-zero elements of column j of s. The function fn
+// takes a row/column index and the element value of s at (i, j).
+func (s *SymBandDense) DoColNonZero(j int, fn func(i, j int, v float64)) {
+ if j < 0 || s.mat.N <= j {
+ panic(ErrColAccess)
+ }
+ for i := 0; i < s.mat.N; i++ {
+ if i-s.mat.K <= j && j < i+s.mat.K+1 {
+ v := s.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ }
+}

MODIFY
mat/symmetric.go
mat/symmetric.go
@@ -45,6 +45,7 @@ type RawSymmetricer interface {
RawSymmetric() blas64.Symmetric
}
+// A MutableSymmetric can set elements of a symmetric matrix.
type MutableSymmetric interface {
Symmetric
SetSym(i, j int, v float64)

MODIFY
mat/triangular.go
mat/triangular.go
@@ -17,6 +17,11 @@ var (
_ Matrix = triDense
_ Triangular = triDense
_ RawTriangular = triDense
+ _ MutableTriangular = triDense
+
+ _ NonZeroDoer = triDense
+ _ RowNonZeroDoer = triDense
+ _ ColNonZeroDoer = triDense
)
const badTriCap = "mat: bad capacity for TriDense"
@@ -28,6 +33,7 @@ type TriDense struct {
cap int
}
+// Triangular represents a triangular matrix. Triangular matrices are always square.
type Triangular interface {
Matrix
// Triangular returns the number of rows/columns in the matrix and its
@@ -39,10 +45,17 @@ type Triangular interface {
TTri() Triangular
}
+// A RawTriangular can return a view of itself as a BLAS Triangular matrix.
type RawTriangular interface {
RawTriangular() blas64.Triangular
}
+// A MutableTriangular can set elements of a triangular matrix.
+type MutableTriangular interface {
+ Triangular
+ SetTri(i, j int, v float64)
+}
+
var (
_ Matrix = TransposeTri{}
_ Triangular = TransposeTri{}
@@ -455,3 +468,73 @@ func copySymIntoTriangle(t *TriDense, s Symmetric) {
}
}
}
+
+// DoNonZero calls the function fn for each of the non-zero elements of t. The function fn
+// takes a row/column index and the element value of t at (i, j).
+func (t *TriDense) DoNonZero(fn func(i, j int, v float64)) {
+ if t.isUpper() {
+ for i := 0; i < t.mat.N; i++ {
+ for j := i; j < t.mat.N; j++ {
+ v := t.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ }
+ return
+ }
+ for i := 0; i < t.mat.N; i++ {
+ for j := 0; j <= i; j++ {
+ v := t.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ }
+}
+
+// DoRowNonZero calls the function fn for each of the non-zero elements of row i of t. The function fn
+// takes a row/column index and the element value of t at (i, j).
+func (t *TriDense) DoRowNonZero(i int, fn func(i, j int, v float64)) {
+ if i < 0 || t.mat.N <= i {
+ panic(ErrRowAccess)
+ }
+ if t.isUpper() {
+ for j := i; j < t.mat.N; j++ {
+ v := t.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ return
+ }
+ for j := 0; j <= i; j++ {
+ v := t.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+}
+
+// DoColNonZero calls the function fn for each of the non-zero elements of column j of t. The function fn
+// takes a row/column index and the element value of t at (i, j).
+func (t *TriDense) DoColNonZero(j int, fn func(i, j int, v float64)) {
+ if j < 0 || t.mat.N <= j {
+ panic(ErrColAccess)
+ }
+ if t.isUpper() {
+ for i := 0; i <= j; i++ {
+ v := t.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+ return
+ }
+ for i := j; i < t.mat.N; i++ {
+ v := t.at(i, j)
+ if v != 0 {
+ fn(i, j, v)
+ }
+ }
+}

mat: add NonZeroDoer interfaces and implementations

Also clean up some documentation and missing type checks related to
tests for NonZeroDoers.