mat: add overlap detection for SymBandDense

mat/shadow.go

@@ -67,6 +67,8 @@ func (m *Dense) checkOverlapMatrix(a Matrix) bool {
 		amat = ar.RawMatrix()
 	case RawSymmetricer:
 		amat = generalFromSymmetric(ar.RawSymmetric())
+	case RawSymBander:
+		amat = generalFromSymmetricBand(ar.RawSymBand())
 	case RawTriangular:
 		amat = generalFromTriangular(ar.RawTriangular())
 	case RawVectorer:
@@ -92,6 +94,8 @@ func (s *SymDense) checkOverlapMatrix(a Matrix) bool {
 		amat = ar.RawMatrix()
 	case RawSymmetricer:
 		amat = generalFromSymmetric(ar.RawSymmetric())
+	case RawSymBander:
+		amat = generalFromSymmetricBand(ar.RawSymBand())
 	case RawTriangular:
 		amat = generalFromTriangular(ar.RawTriangular())
 	case RawVectorer:
@@ -128,6 +132,8 @@ func (t *TriDense) checkOverlapMatrix(a Matrix) bool {
 		amat = ar.RawMatrix()
 	case RawSymmetricer:
 		amat = generalFromSymmetric(ar.RawSymmetric())
+	case RawSymBander:
+		amat = generalFromSymmetricBand(ar.RawSymBand())
 	case RawTriangular:
 		amat = generalFromTriangular(ar.RawTriangular())
 	case RawVectorer:
@@ -196,3 +202,41 @@ func generalFromVector(a blas64.Vector, r, c int) blas64.General {
 		Data:   a.Data,
 	}
 }
+
+func (s *SymBandDense) checkOverlap(a blas64.General) bool {
+	return checkOverlap(generalFromSymmetricBand(s.RawSymBand()), a)
+}
+
+func (s *SymBandDense) checkOverlapMatrix(a Matrix) bool {
+	if s == a {
+		return false
+	}
+	var amat blas64.General
+	switch ar := a.(type) {
+	default:
+		return false
+	case RawMatrixer:
+		amat = ar.RawMatrix()
+	case RawSymmetricer:
+		amat = generalFromSymmetric(ar.RawSymmetric())
+	case RawSymBander:
+		amat = generalFromSymmetricBand(ar.RawSymBand())
+	case RawTriangular:
+		amat = generalFromTriangular(ar.RawTriangular())
+	case RawVectorer:
+		r, c := a.Dims()
+		amat = generalFromVector(ar.RawVector(), r, c)
+	}
+	return s.checkOverlap(amat)
+}
+
+// generalFromSymmetricBand returns a blas64.General with the backing
+// data and dimensions of a.
+func generalFromSymmetricBand(a blas64.SymmetricBand) blas64.General {
+	return blas64.General{
+		Rows:   a.N,
+		Cols:   a.K + 1,
+		Data:   a.Data,
+		Stride: a.Stride,
+	}
+}

mat/vector.go

@@ -597,6 +597,7 @@ func (v *VecDense) MulVec(a Matrix, b Vector) {
 		return
 	case *SymBandDense:
 		if fast {
+			aU.checkOverlap(v.asGeneral())
 			blas64.Sbmv(1, aU.mat, bmat, 0, v.mat)
 			return
 		}