Fix for the optimizer case when expected returns are all same.
Fix for the optimizer case when expected returns are all same.

QuantSoftware/QuantSoftwareToolkit,michaelhuang/QuantSoftwareToolkit,michaelhuang/QuantSoftwareToolkit,QuantSoftware/QuantSoftwareToolkit,QuantSoftware/QuantSoftwareToolkit,michaelhuang/QuantSoftwareToolkit,michaelhuang/QuantSoftwareToolkit,QuantSoftware/QuantSoftwareToolkit,QuantSoftware/QuantSoftwareToolkit,michaelhuang/QuantSoftwareToolkit,michaelhuang/QuantSoftwareToolkit,QuantSoftware/QuantSoftwareToolkit