message: calculation of inverse not necessary
diff: @@ -27,7 +27,7 @@ use std::default::Default;
  pub struct BFGS<'a, T, H>
  where
  T: 'a + Clone + Default + ArgminScaledSub<T, f64>,
  - H: 'a + Clone + Default + ArgminInv<H> + ArgminDot<T, T>,
  + H: 'a + Clone + Default + ArgminDot<T, T>,
  {
  /// Base stuff
  base: ArgminBase<'a, T, f64, H>,
  @@ -36,7 +36,7 @@ where
  impl<'a, T, H> BFGS<'a, T, H>
  where
  T: 'a + Clone + Default + ArgminScaledSub<T, f64>,
  - H: 'a + Clone + Default + ArgminInv<H> + ArgminDot<T, T>,
  + H: 'a + Clone + Default + ArgminDot<T, T>,
  {
  /// Constructor
  pub fn new(
  @@ -53,7 +53,7 @@ where
  impl<'a, T, H> ArgminNextIter for BFGS<'a, T, H>
  where
  T: 'a + Clone + Default + ArgminScaledSub<T, f64>,
  - H: 'a + Clone + Default + ArgminInv<H> + ArgminDot<T, T>,
  + H: 'a + Clone + Default + ArgminDot<T, T>,
  {
  type Parameters = T;
  type OperatorOutput = f64;
  