lapack: rename ComputeEV and add EVNone

lapack/gonum/dsyev.go

@@ -19,9 +19,9 @@ import (
 // at least n, and Dsyev will panic otherwise.
 //
 // On entry, a contains the elements of the symmetric matrix A in the triangular
-// portion specified by uplo. If jobz == lapack.ComputeEV a contains the
+// portion specified by uplo. If jobz == lapack.EVCompute, a contains the
-// orthonormal eigenvectors of A on exit, otherwise on exit the specified
+// orthonormal eigenvectors of A on exit, otherwise jobz must be lapack.EVNone
-// triangular region is overwritten.
+// and on exit the specified triangular region is overwritten.
 //
 // work is temporary storage, and lwork specifies the usable memory length. At minimum,
 // lwork >= 3*n-1, and Dsyev will panic otherwise. The amount of blocking is
@@ -30,7 +30,14 @@ import (
 func (impl Implementation) Dsyev(jobz lapack.EVJob, uplo blas.Uplo, n int, a []float64, lda int, w, work []float64, lwork int) (ok bool) {
 	checkMatrix(n, n, a, lda)
 	upper := uplo == blas.Upper
-	wantz := jobz == lapack.ComputeEV
+	var wantz bool
+	switch jobz {
+	default:
+		panic(badEVJob)
+	case lapack.EVCompute:
+		wantz = true
+	case lapack.EVNone:
+	}
 	var opts string
 	if upper {
 		opts = "U"

lapack/lapack.go

@@ -137,16 +137,22 @@ const (
 	UpdateSchur EVComp = 'V'
 )
 
+// EVJob specifies whether eigenvectors are computed in Dsyev.
+type EVJob byte
+
+const (
+	EVCompute EVJob = 'V' // Eigenvectors are computed.
+	EVNone    EVJob = 'N' // Eigenvectors are not computed.
+)
+
 // Job types for computation of eigenvectors.
 type (
-	EVJob      byte
 	LeftEVJob  byte
 	RightEVJob byte
 )
 
 // Job constants for computation of eigenvectors.
 const (
-	ComputeEV      EVJob      = 'V' // Compute eigenvectors in Dsyev.
 	ComputeLeftEV  LeftEVJob  = 'V' // Compute left eigenvectors.
 	ComputeRightEV RightEVJob = 'V' // Compute right eigenvectors.
 )

lapack/lapack64/lapack64.go

@@ -454,9 +454,9 @@ func Pocon(a blas64.Symmetric, anorm float64, work []float64, iwork []int) float
 // at least n, and Syev will panic otherwise.
 //
 // On entry, a contains the elements of the symmetric matrix A in the triangular
-// portion specified by uplo. If jobz == lapack.ComputeEV a contains the
+// portion specified by uplo. If jobz == lapack.EVCompute, a contains the
-// orthonormal eigenvectors of A on exit, otherwise on exit the specified
+// orthonormal eigenvectors of A on exit, otherwise jobz must be lapack.EVNone
-// triangular region is overwritten.
+// and on exit the specified triangular region is overwritten.
 //
 // Work is temporary storage, and lwork specifies the usable memory length. At minimum,
 // lwork >= 3*n-1, and Syev will panic otherwise. The amount of blocking is

lapack/testlapack/dsyev.go

@@ -55,9 +55,9 @@ func DsyevTest(t *testing.T, impl Dsyever) {
 				}
 
 				work := make([]float64, 1)
-				impl.Dsyev(lapack.ComputeEV, uplo, n, a, lda, w, work, -1)
+				impl.Dsyev(lapack.EVCompute, uplo, n, a, lda, w, work, -1)
 				work = make([]float64, int(work[0]))
-				impl.Dsyev(lapack.ComputeEV, uplo, n, a, lda, w, work, len(work))
+				impl.Dsyev(lapack.EVCompute, uplo, n, a, lda, w, work, len(work))
 
 				// Check that the decomposition is correct
 				orig := blas64.General{

mat/eigen.go

@@ -38,9 +38,9 @@ func (e *EigenSym) Factorize(a Symmetric, vectors bool) (ok bool) {
 	sd := NewSymDense(n, nil)
 	sd.CopySym(a)
 
-	jobz := lapack.EVJob(lapack.None)
+	jobz := lapack.EVNone
 	if vectors {
-		jobz = lapack.ComputeEV
+		jobz = lapack.EVCompute
 	}
 	w := make([]float64, n)
 	work := []float64{0}