{conv,cmat128}: make cmat128.Matrix implement conjugate transpose

cmat128/matrix.go

@@ -13,56 +13,58 @@ type Matrix interface {
 	// It will panic if i or j are out of bounds for the matrix.
 	At(i, j int) complex128
 
-	// T returns the transpose of the Matrix. Whether T returns a copy of the
-	// underlying data is implementation dependent.
-	// This method may be implemented using the Transpose type, which
-	// provides an implicit matrix transpose.
-	T() Matrix
+	// H returns the conjugate transpose of the Matrix. Whether H
+	// returns a copy of the underlying data is implementation dependent.
+	// This method may be implemented using the Conjugate type, which
+	// provides an implicit matrix conjugate transpose.
+	H() Matrix
 }
 
 var (
-	_ Matrix       = Transpose{}
-	_ Untransposer = Transpose{}
+	_ Matrix       = Conjugate{}
+	_ Unconjugator = Conjugate{}
 )
 
-// Transpose is a type for performing an implicit matrix transpose. It implements
-// the Matrix interface, returning values from the transpose of the matrix within.
-type Transpose struct {
+// Conjugate is a type for performing an implicit matrix conjugate transpose.
+// It implements the Matrix interface, returning values from the conjugate
+// transpose of the matrix within.
+type Conjugate struct {
 	Matrix Matrix
 }
 
 // At returns the value of the element at row i and column j of the transposed
 // matrix, that is, row j and column i of the Matrix field.
-func (t Transpose) At(i, j int) complex128 {
-	return t.Matrix.At(j, i)
+func (t Conjugate) At(i, j int) complex128 {
+	return t.Matrix.At(j, i) * complex(1, -1)
 }
 
 // Dims returns the dimensions of the transposed matrix. The number of rows returned
 // is the number of columns in the Matrix field, and the number of columns is
 // the number of rows in the Matrix field.
-func (t Transpose) Dims() (r, c int) {
+func (t Conjugate) Dims() (r, c int) {
 	c, r = t.Matrix.Dims()
 	return r, c
 }
 
-// T performs an implicit transpose by returning the Matrix field.
-func (t Transpose) T() Matrix {
+// H performs an implicit conjugate transpose by returning the Matrix field.
+func (t Conjugate) H() Matrix {
 	return t.Matrix
 }
 
-// Untranspose returns the Matrix field.
-func (t Transpose) Untranspose() Matrix {
+// Unconjugate returns the Matrix field.
+func (t Conjugate) Unconjugate() Matrix {
 	return t.Matrix
 }
 
-// Untransposer is a type that can undo an implicit transpose.
-type Untransposer interface {
-	// Note: This interface is needed to unify all of the Transpose types. In
+// Unconjugator is a type that can undo an implicit conjugate transpose.
+type Unconjugator interface {
+	// Note: This interface is needed to unify all of the Conjugate types. In
 	// the cmat128 methods, we need to test if the Matrix has been implicitly
-	// transposed. If this is checked by testing for the specific Transpose type
-	// then the behavior will be different if the user uses T() or TTri() for a
+	// transposed. If this is checked by testing for the specific Conjugate type
+	// then the behavior will be different if the user uses H() or HTri() for a
 	// triangular matrix.
 
-	// Untranspose returns the underlying Matrix stored for the implicit transpose.
-	Untranspose() Matrix
+	// Unconjugate returns the underlying Matrix stored for the implicit
+	// conjugate transpose.
+	Unconjugate() Matrix
 }

conv/conv.go

@@ -17,6 +17,10 @@ type Complex struct {
 	// their dimensions can not be altered by
 	// clients behind our back.
 	r, i mat64.Matrix
+
+	// imagSign hold the sign of the imaginary
+	// part of the Complex. Valid values are 1 and -1.
+	imagSign float64
 }
 
 var (
@@ -38,7 +42,7 @@ func NewComplex(r, i mat64.Matrix) Complex {
 			panic(matrix.ErrShape)
 		}
 	}
-	return Complex{r: r, i: i}
+	return Complex{r: r, i: i, imagSign: 1}
 }
 
 // Dims returns the number of rows and columns in the matrix.
@@ -55,20 +59,20 @@ func (m Complex) At(i, j int) complex128 {
 		return complex(m.r.At(i, j), 0)
 	}
 	if m.r == nil {
-		return complex(0, m.i.At(i, j))
+		return complex(0, m.imagSign*m.i.At(i, j))
 	}
-	return complex(m.r.At(i, j), m.i.At(i, j))
+	return complex(m.r.At(i, j), m.imagSign*m.i.At(i, j))
 }
 
-// T performs an implicit transpose.
-func (m Complex) T() cmat128.Matrix {
+// H performs an implicit transpose.
+func (m Complex) H() cmat128.Matrix {
 	if m.i == nil {
 		return Complex{r: m.r.T()}
 	}
 	if m.r == nil {
-		return Complex{i: m.i.T()}
+		return Complex{i: m.i.T(), imagSign: -m.imagSign}
 	}
-	return Complex{r: m.r.T(), i: m.i.T()}
+	return Complex{r: m.r.T(), i: m.i.T(), imagSign: -m.imagSign}
 }
 
 // Real returns the real part of the receiver.
@@ -88,7 +92,9 @@ type Imager interface {
 }
 
 // Real is the real part of a complex matrix.
-type Real struct{ Matrix cmat128.Matrix }
+type Real struct {
+	matrix cmat128.Matrix
+}
 
 // NewReal returns a mat64.Matrix representing the real part of m. If m is a Realer,
 // the real part is returned.
@@ -100,31 +106,37 @@ func NewReal(m cmat128.Matrix) mat64.Matrix {
 }
 
 // Dims returns the number of rows and columns in the matrix.
-func (m Real) Dims() (r, c int) { return m.Matrix.Dims() }
+func (m Real) Dims() (r, c int) { return m.matrix.Dims() }
 
 // At returns the element at row i, column j.
-func (m Real) At(i, j int) float64 { return real(m.Matrix.At(i, j)) }
+func (m Real) At(i, j int) float64 { return real(m.matrix.At(i, j)) }
 
 // T performs an implicit transpose.
-func (m Real) T() mat64.Matrix { return Real{m.Matrix.T()} }
+func (m Real) T() mat64.Matrix { return Real{m.matrix.H()} }
 
 // Imag is the imaginary part of a complex matrix.
-type Imag struct{ Matrix cmat128.Matrix }
+type Imag struct {
+	matrix cmat128.Matrix
+
+	// conjSign holds the sign of the matrix.
+	// Valid values are 1 and -1.
+	conjSign float64
+}
 
 // NewImage returns a mat64.Matrix representing the imaginary part of m. If m is an Imager,
 // the imaginary part is returned.
 func NewImag(m cmat128.Matrix) mat64.Matrix {
 	if m, ok := m.(Imager); ok {
 		return m.Imag()
 	}
-	return Imag{m}
+	return Imag{matrix: m, conjSign: 1}
 }
 
 // Dims returns the number of rows and columns in the matrix.
-func (m Imag) Dims() (r, c int) { return m.Matrix.Dims() }
+func (m Imag) Dims() (r, c int) { return m.matrix.Dims() }
 
 // At returns the element at row i, column j.
-func (m Imag) At(i, j int) float64 { return imag(m.Matrix.At(i, j)) }
+func (m Imag) At(i, j int) float64 { return m.conjSign * imag(m.matrix.At(i, j)) }
 
 // T performs an implicit transpose.
-func (m Imag) T() mat64.Matrix { return Imag{m.Matrix.T()} }
+func (m Imag) T() mat64.Matrix { return Imag{matrix: m.matrix.H(), conjSign: -m.conjSign} }