Add tests and documentation

cgo/lapack.go

@@ -19,7 +19,9 @@ const (
 	badIpiv       = "lapack: insufficient permutation length"
 	badLdA        = "lapack: index of a out of range"
 	badNorm       = "lapack: bad norm"
+	badPivot      = "lapack: bad pivot"
 	badSide       = "lapack: bad side"
+	badSlice      = "lapack: bad input slice length"
 	badStore      = "lapack: bad store"
 	badTau        = "lapack: tau has insufficient length"
 	badTrans      = "lapack: bad trans"

native/dlasr.go

@@ -5,9 +5,40 @@ import (
 	"github.com/gonum/lapack"
 )
 
-// Dlasr applies a sequence of plane rotations to a matrix.
+// Dlasr applies a sequence of plane rotations to the m×n matrix A. P(k) is a 2×2
+// rotation matrix defined by s[k] and c[k]. If direct == lapack.Forward, the
+// rotation matrices are applied as P = P(z-1) * ... * P(2) * P(1), while if
+// direct == lapack.Backward they are applied as P = P(1) * P(2) * ... * P(n).
+// If side == lapack.Left, A = P * A, while if side == lapack.Right, A = A * P^T.
+// If pivot == lapack.Variable, the rotation is performed for the (k, k+1) plane,
+// if pivot == lapack.Top, the rotation is performed for the (1, k+1) plane,
+// and if pivot == lapack.Bottom, the rotation is performed for the (k, z) plane.
 func (impl Implementation) Dlasr(side blas.Side, pivot lapack.Pivot, direct lapack.Direct, m, n int, c, s, a []float64, lda int) {
 	checkMatrix(m, n, a, lda)
+	if side != blas.Left && side != blas.Right {
+		panic(badSide)
+	}
+	if pivot != lapack.Variable && pivot != lapack.Top && pivot != lapack.Bottom {
+		panic(badPivot)
+	}
+	if direct != lapack.Forward && direct != lapack.Backward {
+		panic(badDirect)
+	}
+	if side == blas.Left {
+		if len(c) < m-1 {
+			panic(badSlice)
+		}
+		if len(s) < m-1 {
+			panic(badSlice)
+		}
+	} else {
+		if len(c) < n-1 {
+			panic(badSlice)
+		}
+		if len(s) < n-1 {
+			panic(badSlice)
+		}
+	}
 	if m == 0 || n == 0 {
 		return
 	}

native/general.go

@@ -25,7 +25,9 @@ const (
 	badIpiv       = "lapack: insufficient permutation length"
 	badLdA        = "lapack: index of a out of range"
 	badNorm       = "lapack: bad norm"
+	badPivot      = "lapack: bad pivot"
 	badSide       = "lapack: bad side"
+	badSlice      = "lapack: bad input slice length"
 	badStore      = "lapack: bad store"
 	badTau        = "lapack: tau has insufficient length"
 	badTrans      = "lapack: bad trans"