// void dsytrf_(char *uplo, int *n, double *A, int *lda, int *ipiv,
// double *work, int *lwork, int *info);
func dsytrf(uplo string, N int, A []float64, lda int, ipiv []int32) int {
var info int = 0
var lwork int = -1
var work float64
cuplo := C.CString(uplo)
defer C.free(unsafe.Pointer(cuplo))
// pre-calculate work buffer size
C.dsytrf_(cuplo, (*C.int)(unsafe.Pointer(&N)),
nil, (*C.int)(unsafe.Pointer(&lda)), nil,
(*C.double)(unsafe.Pointer(&work)), (*C.int)(unsafe.Pointer(&lwork)),
(*C.int)(unsafe.Pointer(&info)))
// allocate work area
lwork = int(work)
wbuf := make([]float64, lwork)
C.dsytrf_(cuplo, (*C.int)(unsafe.Pointer(&N)),
(*C.double)(unsafe.Pointer(&A[0])), (*C.int)(unsafe.Pointer(&lda)),
(*C.int)(unsafe.Pointer(&ipiv[0])),
(*C.double)(unsafe.Pointer(&wbuf[0])), (*C.int)(unsafe.Pointer(&lwork)),
(*C.int)(unsafe.Pointer(&info)))
return info
}
func dsytrfHelper(uplo Triangle, n int, a []float64, lda int, ipiv []C.integer, work []float64, lwork int) error {
var (
uplo_ = C.char(uplo)
n_ = C.integer(n)
a_ = ptrFloat64(a)
lda_ = C.integer(lda)
ipiv_ = ptrInt(ipiv)
work_ = ptrFloat64(work)
lwork_ = C.integer(lwork)
)
var info_ C.integer
C.dsytrf_(&uplo_, &n_, a_, &lda_, ipiv_, work_, &lwork_, &info_)
info := int(info_)
switch {
case info < 0:
return errInvalidArg(-info)
case info > 0:
return errSingular(info)
default:
return nil
}
}
